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The University of Dodoma
University of Dodoma Institutional Repository http://repository.udom.ac.tz
Natural Sciences Master Dissertations
2017
Diversity of medicinal trees in Unguja
central district, Zanzibar
Haji, Haji Mohd
The University of Dodoma
Haji, H. M. (2017). Diversity of medicinal trees in Unguja central district, Zanzibar. Dodoma: The
University of Dodoma
http://hdl.handle.net/20.500.12661/523
Downloaded from UDOM Institutional Repository at The University of Dodoma, an open access institutional repository.
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DIVERSITY OF MEDICINAL TREES IN UNGUJA CENTRAL
DISTRICT, ZANZIBAR
HAJI MOHD HAJI
MASTER OF SCIENCE IN BIODIVERSITY CONSERVATION
THE UNIVERSITY OF DODOMA
OCTOBER, 2017
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DIVERSITY OF MEDICINAL TREES IN UNGUJA CENTRAL
DISTRICT, ZANZIBAR
By
Haji Mohd Haji
A Dissertation Submitted in Partial Fulfillment of the Requirement for the
Degree of Master of Science in Biodiversity Conservation of the University of
Dodoma
The University of Dodoma
October, 2017
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CERTIFICATION
The undersigned certifies that he has read and hereby recommends for acceptance by
the University of Dodoma a dissertation entitled: “Diversity of medicinal trees in
Unguja Central District –Zanzibar” in partial fulfillment of the requirements for the
degree of Master of Science in Biodiversity conservation at the University of
Dodoma.
………………………………
Dr. Chrispinus D. Rubanza
(SUPERVISOR)
Date …………………………
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DECLARATION
AND
COPYRIGHT
I, Haji Mohd Haji declare that this dissertation is my own original work and that it
has not been presented and will not be presented to any other university for a similar
or any other degree award.
Signature: …………………………………
No part of this a dissertation may be reproduced, stored in any retrieval system, or
transmitted in any form or by any means without prior written permission of the
author or the University of Dodoma.
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ACKNOWLEDGEMENT
I wish to express my thanks and gratitude to the Almighty God for giving me the
courage, ability and guidance through the process of preparation of this dissertation.
Firstly, I would like to give special thanks to my Supervisor Dr. Chrispinus D.
Rubanza for his great assistance from the beginning to the end of this study.
Secondly, I would like to express my gratitude to Mr. Hassan Is-haka Bakari of
Department of Forestry Non-renewable Natural Resources for his useful instructions
of this study. I highly appreciate the contribution of Teacher Ali Abdalla of Ministry
of education and Vocational training Zanzibar and I do express my regards to Mr.
Hussein Abdalla and Mr. Ali Kassim of Zanzibar the Forest Department for their
inventory work with GIS map.
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ABSTRACT
A study was conducted at Marumbi and Uroa villages of Central District of Unguja
Zanzibar to assess diversity of medicinal trees species based on specific objectives:
(1) to determine diversity of medicinal tree species in the two study village forests;
and (2) to determine extent of extraction of medicinal trees: A total of 99 circular
plots (radius, r= 11.28 m) were laid down systematically. Medicinal trees were
identified and recorded against tree tally, and computed for indices of diversity.
Extent of extraction of medicinal trees was assessed using a socio-economic survey.
Semi-structured questionnaires, matrix ranking and interviews were administered
among 48 local community including traditional healers and herbal medicine dealers.
A total of 55 medicinal trees species which belong to 28 families were identified.
Shannon-wiener index (H‟) ranged from 1.44 to 2.899 for Marumbi forest, and from
1.519 to 3.106 for Uroa forest. Simpson index of diversity (D) ranged from 0.108 to
2.287 and from 0.137 to 0.327 for Marumbi and Uroa forests, respectively. The
Simpson index of dominance (C) value ranged from 0.14 to 0.13 at Uroa, and from
0.18 to 0.14 for Marumbi forest. The most dominant species were Polysphaeria
porvofolia, Macphersonia gracilis, Euclea natalensis and Suregada zanzibarensis.
Rare species were Drypetes natalensis, Croton sylvaticus and Vernonia
zanzibarensis. Results revealed over exploitation of medicinal trees in the two
forests. Based on the inherent knowledge of local communities, Croton sylvaticus,
Drypetes natalensis, Pittosporum viridiflorum, Vernonia zanzibarensis and Teclea
simplicifolia were ranked as priority medicinal tree species. It can be concluded that,
the ongoing overexploitation of the medicinal trees could threat sustainability of
medicinal tree species.
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TABLE OF CONTENTS
CERTIFICATION ........................................................................................................ i
DECLARATION AND COPYRIGHT ....................................................................... ii
ACKNOWLEDGEMENT .......................................................................................... iii
ABSTRACT ............................................................................................................... iv
TABLE OF CONTENTS ............................................................................................ v
LIST OF TABLES ..................................................................................................... ix
LIST OF FIGURES ..................................................................................................... x
LIST OF PLATES ...................................................................................................... xi
LIST OF APPENDICES ........................................................................................... xii
LIST OF ABBRIVIATIONS ................................................................................... xiii
CHAPTER ONE ........................................................................................................ 1
1.0 Introduction ........................................................................................................... 1
1.1 Background Information ....................................................................................... 3
1.2 Statement of the Problem ...................................................................................... 5
1.3 Objective of the Study ........................................................................................... 7
1.3.1 Overall Objective ................................................................................................ 7
1.3.2 Specific Objectives ............................................................................................. 7
1.4 Research Questions ............................................................................................... 7
1.5 Significance of the Study ....................................................................................... 7
1.6 Limitation of the Study .......................................................................................... 8
1.7 Scope of the Study ................................................................................................. 8
CHAPTER TWO ....................................................................................................... 9
2.0 Literature Review .................................................................................................. 9
2.1 Theoretical Literature Review ............................................................................... 9
2.1.1 Definitions of Keys Terms ................................................................................. 9
2.1.1.1 Medicinal Plants .............................................................................................. 9
2.1.1.2 Phytopharmaceutical preparation .................................................................... 9
2.1.1.3 Medicine ........................................................................................................ 10
2.1.1.4 Drug ............................................................................................................... 10
2.1.1.5 Herbalist ........................................................................................................ 10
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2.1.1.6 Complementary medicine .............................................................................. 10
2.1.1.7 Traditional healers ......................................................................................... 11
2.1.1.8 Deforestation ................................................................................................. 11
2.1.1.9 Species diversity ............................................................................................ 11
2.1.1.10 Pharmacology .............................................................................................. 12
2.1.1.11 Alternative medicines .................................................................................. 12
2.1.2 Theories underlying the use of herbal medicine ............................................... 12
2.1.2.1 Theoretical Perspectives on Herb-Herb Combination. .................................. 13
2.1.2.2 The holistic healing philosophy of the Greek Medicine ............................... 13
2.2 Empirical Literature Review ............................................................................... 14
2.2.1 An overview on medicinal trees ....................................................................... 14
2.2.2 Influence of policy on sustainability of medicinal trees ................................... 15
2.2.2.1 Legislation and Regulation ............................................................................ 15
2.2.2.2 Zanzibar National Forest Policy .................................................................... 16
2.2.3 Active Ingredients in Medicinal Plants ............................................................ 16
2.2.4 Herbal Medicine Remedy ................................................................................. 17
2.2.5 The Pharmacology of Herbal Plants ................................................................. 18
2.2.6 Diversity of medicinal trees .............................................................................. 19
2.2.6.1 Indices of dominance and diversity ............................................................... 20
2.2.6.2 Shannon-Wiener index of diversity ............................................................... 21
2.2.6.3 Simpson‟s index of dominance ..................................................................... 22
2.2.7 Over-harvesting and Commercial of medicinal trees ....................................... 22
2.2.8 Impact of over-harvesting medicinal Trees ...................................................... 23
2.2.9 Utilization of medicinal Trees .......................................................................... 24
2.2.10 Knowledge Gap .............................................................................................. 27
2.3 Conceptual Frame-work ...................................................................................... 27
2.3.1 Independent variable ........................................................................................ 28
2.3.2 Intermediate variables ...................................................................................... 28
2.3.3 Dependent variable ........................................................................................... 28
CHAPTER THREE ................................................................................................. 30
3.0 Research methodology ........................................................................................ 30
3.1 Description of Study Area ................................................................................... 30
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3.1.1 Economic activities .......................................................................................... 30
3.1.2 Demography ..................................................................................................... 31
3.1.2.1 Central district Population ............................................................................. 32
3.1.3 Climate ............................................................................................................. 33
3.1.4 Geology and Soils ............................................................................................. 33
3.1.5 Vegetation ......................................................................................................... 34
3.2 Research design ................................................................................................... 34
3.3 Sampling Frame and Sampling size .................................................................... 34
3.4 Data collection methods ...................................................................................... 35
3.5 Data collection tools ............................................................................................ 35
3.5.1 Ethno-botanical Surveys ................................................................................... 35
3.5.2 Questionnaires .................................................................................................. 36
3.5.3 Interviews ......................................................................................................... 36
3.5.4 Matrix Ranking ................................................................................................. 36
3.5.5 Plant identification ............................................................................................ 37
3.5.6 Field Survey Method ........................................................................................ 37
3.5.7 Field Procedure ................................................................................................. 38
3.6 Diversity indices .................................................................................................. 39
3.6.1 Tree species diversity ....................................................................................... 42
3.6.2 Simpson‟s Index of dominance ........................................................................ 42
3.7 Data Analysis ....................................................................................................... 42
3.7.1 Determination of tree indices of diversity ........................................................ 43
3.7.2 Simpson‟s index of dominance ........................................................................ 43
3.7.3 Shannon-Wiener index of diversity .................................................................. 43
3.7.4 Data quality and control ................................................................................... 43
3.7.5 Validity ............................................................................................................. 43
3.7.6 Reliability ......................................................................................................... 44
CHAPTER FOUR: RESULTS PRESENTATION AND DISCUSSION OF THE
FINDINGS ................................................................................................................ 45
4.1 Results ................................................................................................................. 45
4.1.1 Medicinal Trees species diversity .................................................................... 45
4.1.1.1 Forest tree inventory and medicinal trees assessment ................................... 46
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4.1.1.2 Simpson‟s index of dominance ..................................................................... 49
4.1.2 Socio-demographic analysis of respondents .................................................... 50
4.1.2.1 Sex of respondents ......................................................................................... 51
4.1.2.2 Level of education ......................................................................................... 51
4.1.3 Extent of extraction of medicinal trees ............................................................. 52
4.1.3.1 Extraction and use of herbal medicine .......................................................... 52
4.1.3.2 Harvesting Medicinal trees parts ................................................................... 53
4.1.3.3 Frequency collection of medicinal trees ........................................................ 54
4.1.3.4 Collection of Priority medicinal trees ............................................................ 54
4.1.3.5 Medicinal trees parts used for trade ............................................................... 56
4.1.3.6 Threatened medicinal trees ............................................................................ 58
4.1.4 Methodology of Harvesting Medicinal trees. ................................................... 58
4.1.4.2 Reasons for declining Medicinal trees .......................................................... 59
4.1.4.3 Effect of improper harvesting medicinal trees .............................................. 60
4.1.5 Conservation measures of medicinal trees ....................................................... 62
4.2 Discussion of the findings ................................................................................... 62
4.2.1 Medicinal Tree species diversity ...................................................................... 63
4.2.1.1 Index of dominance ....................................................................................... 64
4.3 Assessing extent of harvesting Medicinal Trees. ................................................ 64
4.4 Impact of harvesting of Medicinal trees .............................................................. 65
4.4.1 Methods of harvesting diversity of medicinal trees ......................................... 67
4.4.2 Collection medicinal trees for trade ................................................................. 68
4.5 Conservations measures of medicinal trees ......................................................... 69
CHAPTER FIVE: CONCLUSION, RECOMMENDATIONS AND AREAS
FOR FURTHER STUDY ........................................................................................ 70
5.1 Conclusion ........................................................................................................... 70
5.2 Recommendations ............................................................................................... 71
5.3 Area for further study .......................................................................................... 72
REFERENCES ........................................................................................................ 73
APPENDICES .......................................................................................................... 84
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LIST OF TABLES
Table 1: Diversity Index of Medicinal Trees ..................................................... 20
Table 2: Indices of dominance (C) and diversity (H‟) values ............................ 21
Table 3: Mostly used parts of medicinal plants .................................................. 25
Table 4: Medicinal trees found at Jozani forest reserve ..................................... 26
Table 5: Human ppopulation as of 2013 ............................................................ 33
Table 6: Tree sampling parameters for Marumbi and Uroa village forests,
Central district, Unguja ........................................................................ 39
Table 7: The values of tree stocking and species richness ................................. 46
Table 8: Diversity indices of medicinal trees ..................................................... 46
Table 9 (a): Medicinal Trees species list indigenous to Marumbi and Uroa Village
forests, central District, Unguja............................................................ 47
Table 9 (b): Medicinal Trees species list indigenous to Marumbi and Uroa Village
forests, central District, Unguja (Continued) ....................................... 48
Table 10: Dominant value (C) of medicinal trees ................................................ 50
Table 11: Sex of respondents ............................................................................... 51
Table 12: Level of education of the respondents.................................................. 51
Table 13: Threatened medicinal trees.................................................................. 57
Table 14: Methods of collection medicinal trees ................................................. 58
Table 15: Conservation measures of medicinal trees ........................................... 62
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LIST OF FIGURES
Figure 1: Conceptual frame-work ............................................................................. 29
Figure 2: Map location of Uroa forest study area. ..................................................... 31
Figure 3: Location to show Marumbi forest study area ............................................ 32
Figure 4: Map plot layout of Uroa Forest reserve ..................................................... 40
Figure 5: Map plot layout of Marumbi forest ............................................................ 41
Figure 6: Extraction and use of medicinal trees ........................................................ 52
Figure 7: Harvesting parts of medicinal trees ............................................................ 53
Figure 8: Frequency collections of medicinal trees ................................................... 54
Figure 9: Priority medicinal trees .............................................................................. 55
Figure 10: Medicinal trees parts used for trade ......................................................... 56
Figure 11: Reasons for declining medicinal trees. .................................................... 60
Figure 12: Effects of improper harvesting Medicinal trees ....................................... 61
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LIST OF PLATES
Plate 1: Priority medicinal trees (A) Monanthotaxis fornicata (B) Teclea
simplicifolia ................................................................................................. 55
Plate 2: Herbal shop sells (A) roots (B) barks of Pittosporum viridiflorum ............ 57
Plate 3: Herbalists display uprooting method of MTs .............................................. 59
Plate 4: Show rarity medicinal trees (A) Croton sylvaticus (B) Drypetes natalensis61
Plate 5: Improper collection of medicinal trees ........................................................ 69
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LIST OF APPENDICES
Appendix 1: Diversity of medicinal trees in Unguja –Central District Zanzibar ..... 84
Appendix 2: Title: Diversity of medicinal trees in Unguja Central District
Zanzibar. ............................................................................................... 85
Appendix 3: Diversity of medicinal trees in Unguja Central District-Zanzibar ....... 87
Appendix 4: Medicinal Trees Data Collection In Villages Forests. ......................... 90
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LIST OF ABBRIVIATIONS
HIMA Hifadhi Misitu ya Asili
WHO World Health Organization
IUCN International Union of Conservation of Nature
RGZ Revolutionary Government of Zanzibar
ZTMC Zanzibar Traditional and Alternative Medicines Council
GPS Geographical Positioning System
Ha Hectare
REDD Reduce Emissions from Deforestation and Forest Degradation
CAM Complementary and Alternative Medicine
USNCI United State National Cancer Institute
API Active Pharmaceutical Ingredient
HPM Herbal Medicine Product
UNESCO United Nations Educational Scientific and Cultural Organization
MOHSW Ministry of Health and Social Welfare
DFNR Department of Forest and Non-Renewable Resources Zanzibar
PMTs Priority Medicinal Trees
MTs Medicinal Trees
TAM Traditional and Alternative Medicine
ZTMPA Zanzibar Traditional medicine Policy Act
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CHAPTER ONE
1.0 Introduction
Globally over-exploitation of indigenous medicinal plants has become a serious
challenge especially in the developing world where healthcare systems and
livelihoods depend largely on herbal medicines (Assefa et al., 2014). Medicinal trees
species are threatened in many countries including East Africa and Tanzania in
particular (Fennel et al., 2004). These priority medicinal trees include Warburgia
salutaris, Warburgia ungandensis, Cassine transvalensis, Alepidea amatyambica
and Erythrophleum lasianthum (Fennel et al., 2004). The increasing demand for
herbal medicines encourages collectors and traders to decimate natural populations
of important medicinal plants. Global interest particularly from the Western
pharmaceutical industry exacerbates exploitation (Williams, 2000). Some South
African medicinal plants are already on the brink of extinction in the wild
(Geldenhuys, 2004). Report from IUCN has identified medicinal Plant species
including Goldenseal (Hydrastis Canadensis) that have become threatened by non-
sustainable harvest and other factors (IUCN, 2002). According to Walter and Gillett,
(1998), about 34 000 species or 8 percent of the world's flora are threatened with
extinction. Approximate 52 000 plant species are used medicinally.
Over-harvesting has placed many medicinal species at risk of extinction as well as
commercial exploitation is another major threat which influences the indigenous
medicinal trees to become rare (Cunningham et al., 2002).There are evidences that
show decline of rich indigenous knowledge about the use of medicinal trees with
regard to types, distribution, ecology and management of medicinal plants
(Hamilton, 2004).In recent studies of ethno-botanical and ethno-pharmaceutical
studies have been conducted and describe traditional herbal products and legalize
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their use for treatment of human diseases (Light et al., 2005). The global demand for
herbal medicine has been on the rise (Srivastava, 2000; Light et al., 2005), which
some valued indigenous plant species has become threatened (Williams et al., 2000;
Shingu, 2005). However, less is known on the effect of extraction of medicinal trees
in Tanzania and Zanzibar in particular.
A Study conducted on north-western region of Tanzania has recorded top ten priority
medicinal trees species are very scarce due to improper harvesting to near extinction
in some region like Tabora, Shinyanga and Simiyu regions (Ng‟atigwa et al.,1999).
According to the latter authors, a total of 10 species comprising Securidaca
longipedunculata, Zanha africana, Cassia abbreviata, Entada abyssinica, Turraea
fischeri, Albizia anthelmintica, Entandrophragma bussei, Combretum zeyheri,
Zanthoxylum chalybeum and Terminalia sericea have been recognized as priority
medicinal tree species indigenous to Tabora, Shinyanga and Simiyu regions of north
western Tanzania(Ng‟atigwa et al.,1999). Medicinal plant gatherers are familiar with
which species are difficult to find, either because of limited geographical
distribution, habitat destruction or over-exploitation (Hamilton, 2004).Despite
limited information on the population biology of medicinal plants, it is possible to
classify target plant species according to demand, plant life-form, part used,
distribution and abundance (Cunningham, 1990).The use of traditional medicines
and medicinal plants in most developing countries as therapeutic agents has been
widely documented (WHO, 1996; IUCN, 2007).
The World Health Organization (WHO) estimated that 80% of the populations of
developing countries rely on traditional medicines, mostly plant drugs, for their
primary health care needs (Schmincke, 2003).Medicinal plants represent a consistent
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part of the natural biodiversity endowment of many countries in Africa (Okigbo et
al., 2008).Nowadays, natural medicines are gaining prominence, because they are
economical, easily available and relatively free from side effects (Cunningham,
1991).Although, less has been done to investigate medicinal trees efficacy, herbal
cure is gaining worldwide acceptance and has emphasized on modern scientific
exploration, extraction and evaluation of medicines from plants. There is an urgent
need to develop appropriate conservation strategies to promote sustainable use of
medicinal plants through improved harvesting regime, domestication and monitoring
(Cunningham, 1991).
1.1 Background Information
Medicinal plants are plants containing inherent active ingredients used to cure
disease or relieve pain (Okigbo et al., 2008). Many of the modern medicines are
synthetic substance derived from medicinal plants, for example, aspirin (Assefa et
al., 2014). The use of traditional medicines and medicinal plants in most developing
countries as therapeutic agents for the maintenance of good health has been widely
documented (UNESCO, 1996). Medicinal plants represent a consistent part of the
natural biodiversity endowment of many countries in Africa (Okigbo et al., 2008).
Evidences show that utilization of medicinal plants may have direct link with
declining of population and extinctions of plant species (Cunningham, 2002). There
are evidences suggest the use of herbal medicine among many African countries
whereby medicinal plants drawn from a pool of plant species have been used for
medicinal purposes (Alves and Rosa, 2007).
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Medicinal plants are collected in the forests which are normally being degraded due
to over-collection (Kuipers, 1997).A few examples include Phytolacca dodecandra
and Catharanthus roseus, are collected and the extract made out is normal used as an
effective molluscicide to control Schistosomiasis (Kuipers, 1997).According to
(Alves et al., 2007) Harpagophytum procumbens is used to produce a crude drug and
exported in Botswana, Lesotho, Namibia and South Africa. Hibiscus sabdariffa is
exported from Sudan and Egypt (Alves et al., 2007).Pausinystalia yohimbe is
exported from Cameroon, Nigeria and Rwanda. Rauvolfia vomitoria is used to cure
multiple human ailments and is exported from Madagascar, Mozambique and Zaire
(Alves et al., 2007).Facts gathered from studies conducted in various parts of
Tanzania (Green et al, 1996; Ng‟atigwa, 1999; Tanya et al., 2001) show knowledge
among pastoralists on the use of medicinal plants in animal and human healthcare.
Priority traditional medicinal trees have been reported in East African countries used
for human, livestock healthcare, and those used for protecting stored grains against
pest infestation in Mwingi district (Grace et al., 2010). Among 18 species recorded
were regarded as priority medicinal plants for human health. Some of the species for
instance Solanum renschii, Populus ilicifolia were already known to be rare species
due to over-harvesting and habitats conversion (Grace et al., 2010).
In Tanzania, deforestation is taking place in many agro-ecologies which is
threatening the ecosystem and sustainability of medicinal trees. Uluguru Mountain
for instance timber harvesting is associated to the loss of species with multiple uses
such as Ocotea usambarensis, other anthropogenic activities are threatening the
availability of Landolphia buchananii, while Satureja biflora and Vangueria infausta
are affected by the root cuttings by the local community (Hamisy et al., 2000).
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Similar study conducted at Uluguru Mountains in Tanzania has shown that woody
plant communities (trees and shrubs) are more used by the traditional healers than
the non-woody (climbers and herbs) communities, (Hamisy et al., 2000). These
medicinal plant resources are collected from the lowland forests and Miombo
woodlands. Medicinal plants are used to treat various human diseases and
domesticated animals and crops (Hamisy et al., 2000).
Herbal medicine is used extensively by most people in Zanzibar, where by
harvesting of medicinal plant species has been a part of primary health care (Caroline
et al., 2012).Zanzibar traditional and alternative medicine council (ZTAMC) has
identified a number of spices that includes Monanthotaxis fornicata, Zizyphus
mauritiana, Bridelia micrantha, Milicia excelesa,Toddalia asiatica and caesalpinia
bonducela medicinal plants that are harvested regularly for medicinal use and
tourism( Kombo et al., 2002). As of now, over 99 % of the population in the Island
uses traditional medicine either directly or indirectly (Caroline et al., 2012). This
means that care must be taken to maintain the effectiveness, presence and validity of
healers and medicinal plants is of upmost importance (Baylor, 2015). Medicinal and
spice plants are widely collected in Zanzibar and this activity is contributing
significantly to socio-economic well-being of the societies (DCCFF, 2003).
1.2 Statement of the Problem
The threat of diversity medicinal trees species at Uroa and Marumbi forests is central
challenges to the current study. Baylor, (2015) mentioned more 42 plants including
species Todalia asiatica, Vernonia zanzibarensis,Clausena anisata,Suregada
zanzibarensis and Zizyphus mauritiana in Zanzibar Island those are either lost
completely or harder to find them due to excessive harvesting,(Baylor, 2015).
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Reports from one study of Jozani Forest showed that some species of medicinal trees
are endangered example Pittosporum viridiflorum, Monanthotaxis fornicata and
Croton sylvaticus and Vernonia zanzibarensis is endemic species through harvesting,
other species are disappearing because of timber trees exploitation (Nahonyo et al.,
2002; Nahonyo et al., 2005).
The adverse result of medicinal plants due to excessive harvesting of medicinal trees
could lead to decline or extinctions of medicinal plants (Brown et al., 1997).Studies
have revealed that some medicinal trees specie in the Island are threatened due to
excessive exploitation namely Drypetes natalensis,Teclea simplicifolia,Croton
sylvaticus and Rowsonia lucida (Kombo.,2002;Makame.,2013). More than 90 % of
the population in Zanzibar uses traditional medicine for the treatment of various
diseases (MOHSW, 2008:1; Larson, 2008). Conforming to IUCN,(2014), there are
between 50,000 and 80,000 angiosperm species used for medicinal purposes around
the world, about 15,000 medicinal plants species are threatened with extinction due
to over-harvesting and habitat change IUCN,(2014).A species of Himalayan yew tree
that is used to produce Taxol, a chemotherapy drug used to treat cancer for instance
is being pushed to the brink of extinction by over-harvesting for medicinal purposes
and collection for fuel, scientists warned (IUCN, 2007)
The decline in the natural habitat has led to over harvesting of the available
medicinal plants to meet the increasing local demand and for sale to the urban
population (Owuor et al., 2006).Therefore, the current study has investigated impact
of harvesting diversity of medicinal trees species at selected village‟s forests of
Marumbi and Uroa.
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1.3 Objective of the Study
1.3.1 Overall Objective
To asses impact of extraction of herbal medicine on diversity of medicinal trees
species of Marumbi and Uroa in Central District of Unguja Island Zanzibar.
1.3.2 Specific Objectives
i. To determine diversity of medicinal tree species at Uroa and Marumbi
forests.
ii. To assess the extent of extraction of medicinal trees diversity in the two
villages.
1.4 Research Questions
1. What is the medicinal trees species diversity of the Marumbi and Uroa
forests?
2. What is the magnitude of extraction of medicinal trees diversity in the study
area?
1.5 Significance of the Study
Finding presented in the current study provide important contribution to traditional
healers and local people in several ways. It would help conservation biologists to
perceive vulnerable and endangered herbal species.The conservation of medicinal
plants as part of the regulation is a crucial goal that deserves more focus. Without
improving the conservation effort, the loss of both the physical plant as well as
knowledge of treatments is eminent (Baylor et al., 2015). Most traditional healers
and local people in the Islands and Tanzania also East Africa at large depend on
herbal medicines although; they have no adequate knowledge about the status of all
medicinal trees in the Island. Findings of the study have provided necessary inputs
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for the protection of forest in Zanzibar. It would help on the knowledge input of
species diversity of medicinal trees at village of Marumbi and Uroa in the Central
District of Unguja Island.
1.6 Limitation of the Study
The information on plant species used for medicine was very limited. Few people
like traditional healers and old people had traditional knowledge of herbal medicine
and the specialist officers of Forest Department in Zanzibar. The study was set up in
sample plots in forests of coral rags of Uroa and Marumbi villages at Central District
of Unguja Zanzibar Island. Herbal remedies of Traditional healers of selected
villages rely on the two forests and their certain measures sometime ignoring the
basic medical prescription. Furthermore, a financial constraint is another factor; the
fund is limited since a lot of money was spent for data collection in field, transport
and subsistence during the study.
1.7 Scope of the Study
The study was restricted to Marumbi and Uroa villages in Unguja Central District-
Zanzibar. The study has confirmed of over-harvesting of diversity of medicinal trees
which is influenced by anthropogenic activities on diversity of medicinal trees.
Impact of extraction of herbal medicine on diversity of medicinal trees species has
been observed. The forest of this village has been conserved by the government
because of forest destruction. The reason to select Uroa forest is because most herbal
extractors are well known to go within this forest due to diversity of medicinal trees
and also to make comparison of diversity indices of medicinal trees between the two
forests.
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CHAPTER TWO
2.0 Literature Review
This chapter presents different literature review related to sustainable management of
medicinal trees. Theoretical reviews presents as well as empirical literatures are
presented.
2.1 Theoretical Literature Review
The purpose of this part is to examine concept of theories and knowledge that has
accumulated with regard to diversity of medicinal trees. The theoretical literature
review helps to establish what theories already exist, relationships between them and
to develop new hypotheses to be tested. A brief account definition of key terms is
presented.
2.1.1 Definitions of Keys Terms
2.1.1.1 Medicinal Plants
Medicinal plant is any plant used in order to relieve, prevent or cure a disease or to
alter physiological and pathological process, or any plant employed as a source of
drug or their precursors (Arias, 1999).Herbal medicine also called botanical
medicine or phytomedicine refers to using plant seeds, berries, roots, leaves, bark, or
flowers for medicinal purposes (Schmincke, 2003).
2.1.1.2 Phytopharmaceutical preparation
Phytopharmaceutical preparation is any manufactured herbal medicine obtained
exclusively from plants (aerial and non-aerial including parts, juices, resins and oil),
either in the crude state or as a pharmaceutical formulation (Williamson et al., 1996).
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2.1.1.3 Medicine
Medicine is a product prepared according to legal and technical procedures that is
used for the diagnosis, prevention and treatment of disease and has been
scientifically characterized in terms of its efficacy, safety and quality (WHO, 1992).
2.1.1.4 Drug
Drug is a pharmacologically active compound, which is a component of a medicine,
irrespective of its natural, biotechnological or synthetic origin. Evidences show
efforts on searching for various drugs active ingredient against tumours, viruses and
cardiovascular and tropical diseases is a priority (Fennel et al., 2004). The largest
research fields, as defined by the number of publications describing bioactive plant-
derived compounds includes anti-tumour drugs, antibiotics, drugs active against
tropical diseases, contraceptive drugs, anti-inflammatory drugs, immunomodulators,
kidney protectors and drugs for psychiatric use (Hamburger and Hostettman, 1991).
2.1.1.5 Herbalist
Herbalist refers to someone who specializes in handling herbs for medicinal purposes
as well as focuses on growing herbs, while others may harvest or collect herbs in the
wild, and some offer herbal prescriptions and advice. In many cases, herbalist
performs all three tasks, managing his or her own stock of herbs to ensure that they
are of high quality (Vallence et al., 2006).
2.1.1.6 Complementary medicine
Complimentary medicine or complementary alternative (CAM) medicine used
together with conventional medical treatments in approaches, not proven by using
scientific methods, it "complements". Integrative medicine (or integrative health) is
the combination of practices and methods of alternative medicine with conventional
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medicine (Astin, 1998; Hassan et al., 2009). Complementary medicine may involve
non-traditional medical practices, but is undertaken along with traditional healing
approaches. Alternative medicine implies using only nontraditional methods (Ernst,
1995).Some healing therapies are based on Ancient Chinese beliefs, like acupuncture
and the use of certain herbal compounds. Others focus on Hindu, or Ayurvedic,
therapies including diet changes, the practice of yoga, and emphasizing the
connection of mind, body, and spirit (Ernst, 1995; Hassan et al., 2009).
2.1.1.7 Traditional healers
The traditional healers refers to individuals who use the health practices, approaches,
knowledge and beliefs incorporating plant, animal and mineral-based medicines,
spiritual therapies, manual techniques or diagnose and prevent illnesses or maintain
well-being (Schmincke, 2003).
2.1.1.8 Deforestation
Deforestation refers to the removal of a forest or stand of trees where the land is
thereafter converted to non-forest use. Examples of deforestation include conversion
of the forestland to agricultural farmland and human settlements. Main drivers of
deforestation includes trees are being cut for firewood or charcoal and timber,
(Brown, 2002).
2.1.1.9 Species diversity
Species diversity is defined as the number of different species in a particular habitat
in relative frequencies while species richness is the actual number of different
species in the forest (Harrison et al., 2007). Species biodiversity index increases with
the number of species in the community but in practice, biological communities does
not exceed 5.0 (Kent and Coker, 1992).Species diversity is determined by Shannon
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Winner Index and forests with low Shannon Winner Index have low number of
species.
2.1.1.10 Pharmacology
Pharmacology is the scientific study of the actions and interactions of drugs within a
living organism (Astin, 1998). It includes the study of pharmacological substances
which can be used in the treatment, management, and cure of disease. When external
drugs, whether pharmaceutical or otherwise, enter the body of a person or animal
they become the study of a pharmacologist (Muchugi, 2007). Pharmacology science
encompasses the study of drugs that alter the functions of a given person or
organism. These drugs can be medicinal or not. As an official science, the study
dates back to the 1840s and is not to be confused with pharmacy, which links health
sciences with chemical sciences (Astin, 1998).
2.1.1.11 Alternative medicines
Alternative medicines is any practice that is put forward as having the healing effects
of medicine but is not based on evidence gathered using the scientific method
(Mugisha et al.,2005). It consists of a wide range of health care practices, products
and therapies, using alternative medical diagnoses and treatments which typically
have not been included in the degree courses of established medical schools or used
in conventional medicine. Examples of alternative medicine include homeopathy,
naturopathy, chiropractic, and acupuncture (Batugal et al., 2004).
2.1.2 Theories underlying the use of herbal medicine
A brief account on main theories that govern the use of herbal medicine is presented.
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2.1.2.1 Theoretical Perspectives on Herb-Herb Combination.
The concept and practice of Chinese medicine is derived from the accumulation of
empirical evidence and subsequent deduction to form a series of theories, many of
which were borrowed from philosophical thoughts such as the balance between yin
and yang and the interrelationship among the “five elements (wu-xing)” within the
body (Zhou et al., 2012).Chinese medicine is based on the theory that the occurrence
and development of diseases are caused by an imbalanced status (e.g., excessive
“coldness” or “heat”) in various body parts (e.g., the zang- and fu-organs), and the
use of medicaments or other means such as acupuncture and physical manipulation
can restore such imbalance so as to re-establish a state of equilibrium (homeostasis)
(Zhou et al., 2012). Based on the latter theories, guidelines have been developed on
application of Chinese herbal medicine against specific ailments. The system
provided the basis for prescription by Chinese medical doctors (Zhou et al., 2012).
The latter authors further note that, most Chinese medicine prescriptions contain
more than one medicinal plant and /or animal /mineral substance.
2.1.2.2 The holistic healing philosophy of the Greek Medicine
The holistic healing of Greek Medicine (460-377BC) states that Man is essentially a
product of nature, or the natural environment. Health is living in harmony with
nature, and disease results when this harmony and balance are upset, (Hoffman,
1990). Healing is restoring this lost harmony and integration. Man and all other
living beings on this planet grew and evolved within this all-pervasive biosphere, and
have been relying on it for their survival, for food and medicine, for millions of years
(Hoffman, 1990). The use of medicinal plants in healing is not exclusive to the
human species; when animals whether domesticated or those in the wild get sick or
feel unwell, so stop eating and munch of healing herbs used until animal feels better.
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Herbal medicine amongst humans first evolved as an imitation of this universal
healing practice of the animal kingdom (Hoffman, 1990). And so, herbal medicine is
a universal practice among all the world's traditional medical systems, which
developed systems or models of herbal healing based on the holistic healing
principles and concepts inherent to that system (Hoffman, 1990).
2.2 Empirical Literature Review
Study reviews the most relevant studies about herbal medicine. Describing the
overview of the problem, capability of herbal plants in treating diseases, number of
medicinal trees recognized for medicinal value and Pharmacology of herbal plants.
2.2.1 An overview on medicinal trees
Plants have been used for medicinal purposes for most people worldwide.
Indigenous cultures such as African and Native American used herbs in their healing
rituals, while others developed traditional medical systems such as Ayurveda and
Traditional Chinese Medicine in which herbal therapies were used (Assefa et al.,
2014). Researchers found that people in different parts of the world managed to
employ the same or similar plants for the same purposes (Ernst, 2002). Since ancient
times, plants had been an important source of preventive and curative for people and
their live stocks. Today, records of the 422,000 plants species documented
worldwide are reported to have medicinal value, and many are used for medical
purposes (Hamilton, 2004).Herbal medicine is used to treat many conditions, such as
asthma, eczema, premenstrual syndrome, rheumatoid arthritis, migraine, menopausal
symptoms, chronic fatigue, irritable bowel syndrome, and cancer, and many others
(Wink, 2012).The trades in medicinal plants products provide income and
employment to millions of people living in low-income nations. The global market
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for herbal medicines is estimated to be worth USD 40-60 billion annually
(McMullin, 2011).
In spite of the enormous benefits obtained from herbal medicine, studies have found
many plants used for medical purposes and raise serious concern about the existence
of the species due to over-extraction, commercial and deforestation. In Ivory Coast
for example Garcinia afzelii is considered threatened species due to harvesting for
the chewing stick trade (Ake-Assi, 1988).Destructive harvesting of Griffonia
simplicifolia, Voacanga thuoarsii and Voacanga africana fruits for the international
pharmaceutical market is also of concerned (Ake-Assi, 1988).
2.2.2 Influence of policy on sustainability of medicinal trees
According to RGZ (2008) Traditional and alternative medicine policy realizes the
uses of Traditional medicine and promote the traditional medicine integration into
the national healthcare system; alleviate poverty by enhancing household incomes
through promoting conservation, cultivation, harvesting and trade in medicinal plants
and other medicinal resources; contribute to national economic growth through
registration, licensing and other revenue collection measures. Zanzibar Traditional
and Alternative Medicine Policy, RGZ, (2008).
2.2.2.1 Legislation and Regulation
It has not been any comprehensive legislation and regulation of TAM in Zanzibar.
The practice of traditional medicine has been performed without control of the
government. Importation and exportation of medicinal and herbal products however
was controlled under the Agricultural legislation. The Ministry of Health and social
welfare (MOH and SW) with support from the WHO (2000) has developed a draft
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Traditional medicine legislation that should regulate traditional medicine practice in
the country ZTAM P, RGZ, (2008).
2.2.2.2 Zanzibar National Forest Policy
Zanzibar Forestry Policy of 1996 (RGZ, 1999) refer to protect, conserve and develop
forest resources for social, economic and environmental benefit of the present and
future generations of the people of Zanzibar” (Silima, 2010).
2.2.3 Active Ingredients in Medicinal Plants
An active ingredient (AI) is the substance in a pharmaceutical drug or a pesticide that
is biologically active. Bio-active secondary metabolites of plants (phytochemicals)
are Saponins, Tannins, Flavornoids, Alkaloids, and Anthraquinones, Cardiac
glycosides and Cyanogenic glycosides. The pharmacological and other beneficial
effects of anti- nutritional factors in plants have been reviewed (Soetan, 2008). The
presence of these secondary metabolites in plants explains the various uses of plants
for traditional medicine. The similar terms active pharmaceutical ingredient (API)
and bulk active are also used in medicine, and the term active substance may be used
for pesticide formulations (Hamilton et al., 2000).
Whole herbs contain many ingredients, and they may work together to produce a
beneficial effect. The effectiveness of the herbs is determined by many factors such
as climate, ecology and soil quality in which plants grow as well as the way of
harvesting and processing (Bausell, 2007).
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2.2.4 Herbal Medicine Remedy
A drug obtained from tropical plants is quinine, used as a cure for malaria which is
extracted from the bark of several species of the genus Cinchona (Wink, 2012). All
species are small evergreen trees with a hard thick grey bark growing in the valleys
of the Andes of southern America. There are various alkaloids obtained from
Cinchona bark is quinine, with other numerous important alkaloids such as
Cinchonine, Cinchonidine and Quinidine (Wink, 2012).
Herbal supplements are best taken under the guidance of a trained health care
provider. For example, one study found that 90 % of arthritic patients use alternative
therapies, such as herbal medicine (Hamilton, 2008). Example Ginkgo (Ginkgo
biloba) has been used in traditional medicine to treat circulatory disorders and
enhance memory (Kennedy et al., 2007).Recent studies have identified new
compounds obtained from medicinal plant discovered in Madagascar, which is likely
to provide help curb the epidemic of antibiotic-resistant diseases (Wang et al., 2006).
However, new classes of anti-viral drugs derived from plants such as star anise
provide unique hope for combating potential epidemic viral diseases such as flu
(Delvaux et al., 2009). Drugs to fight life-threatening diseases such as diabetes, HIV,
and diarrhea and even substances to protect crops from slugs are being developed
from plants, micro-organisms, amoebae, and other species from African countries
such as Egypt, Somalia, Libya, and Gambia (Barnett, 2006;Ermias et al., 2008).
Scholars have calculated number of plant species which have at one time or another
been used in some culture for medicinal purposes. An enumeration of the WHO from
the late 1970s listed 21 000 medicinal species (Penso, 1980). However, in China
alone 4 941 of 26 092 native species are used as drugs in Chinese traditional
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medicine (FAO, 1997) which is about 18.9 percent of all trees species. If this
proportion is calculated for other well-known medicinal floras and then applied to
the global uses of medicinal trees will be total of 422 000 flowering plant species
(Hamilton, 2008; IUCN, 2012). It can be estimated that the number of plant species
used for medicinal purposes is more than 50,000 species (Geldenhuys, 2004).
2.2.5 The Pharmacology of Herbal Plants
The pharmacology, toxicology and pharmacokinetics of these herbal medicines are
not well researched (Grace et al., 2002; Nibret et al., 2010). Efforts should be made
by mainstream health professionals to provide validated information to traditional
healers and patients on the judicious use of herbal remedies (Ernst, 2002). The report
from WHO in (2000) revised Malaria cases in Africa and found that 59 plant species
were cited for the treatment of Malaria and related diseases (Okigbo et al., 2008).
The study has also identified and documented the anti-malarial use, probably, for the
first in Ghana of three species namely Haematostaphis barteri, Monanthotaxisis sp.
and Strychnos innocua and first time use of Khayasenegalensis, Haemastostaphis
barteri, Mitragyna inermis, Monanthotaxis sp., Eucalyptus camaldulensis,
Cochlospermum tinctorium and Acanthospermus hispidum for the treatment of
typhoid fever and first time usage of Pittosporus betulinus and Vigna subterranean
for the treatment of plenty of diseases (Okigbo et al., 2008). Majority of healers
claim to treat malaria between 4-7 days, typhoid, within seven days and piles1 -2
weeks. The study has potential sources of remedies for the treatment of the three
selected diseases, malaria, typhoid fever and piles (Geldenhuys, 2004).
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2.2.6 Diversity of medicinal trees
The studies were carried out in different forest locations to analyze the species
diversity of medicinal trees and plant diversity, Misonge et al. (2015). Simpson‟s
index, Smith with Wilson‟s index of evenness and Shannon-Weiner index were used
to assess the diversity of medicinal trees Norhajar et al. (2010). Simpson‟s Index of
diversity (Krebs, 1989) and is equal to the probability of picking two organisms at
random that are of the same species. It is inversely related to the probability that two
individuals picked at random belong to different species. Therefore the greater the
value of dominance index, the lower is the species diversity in community and vice
versa. The measurements of species diversity; the Simpson's index (D) and the
Shannon Wiener index (H), are common indices used to assess species
richness,abundance and eveness which may recommend conservation measures
Makame, N,(2013). Simpson gives the probability of any two individuals drawn at
random from an infinitely large community belonging to different species (Robert
and Thomas, 2001). A high level of Simpson‟s index (close to 1) means a high level
of dominance and poor species. The species diversity indicated in the Table 1.
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Table 1: Diversity Index of Medicinal Trees
2.2.6.1 Indices of dominance and diversity
Wilson (2006), defined species diversity is the number of different species in a
particular area and their relative frequencies. It gives information on community
composition and abundance of different species. In other words, species diversity
considers the number of species and the number of individuals in each of the species
(Maganga, 1999). Shannon-Wiener index of diversity (H‟) and Sampson‟s index of
dominance (C) is used to assess forest variations. Table 2; Bernado, (2009); and
Kaniki, (2010) showed how indices of diversity are useful in determining, comparing
and assessing variations of forests tree species and forest condition(s).
Vegetation type Location Shannon
Index (H)
Simpson
Index (D)
References
Logged forest
reserve
Malasia 4.32-5.18 0.869-0.976 Norhajar et
al. (2010)
Mola Forest
reserve
Mafia
Tanzania
3.55-2.32 0.042-0.021 Swai et
al.(2011)
Juani Forest
reserve
Mafia
Tanzania
2.55-2.03 0.11-0.021 Swai et
al.(2011)
Disturbed forest Mabira central
Uganda
2.48 – 0.110 0.88-0.04 Samson et
al.(2015)
Undisturbed
forest
Mabira central
Uganda
2.98-2.78 0.92-0.910 Samson
et al.(2015)
Kiwengw Forest
reserve
Zanzibar 1.20-1.39 0.878-0.18 Makame,
(2013)
Mt Kenya
botanical garden
Kiambu Kenya 2.23-3.93 0.16-0.097 Misonge et
al.(2015)
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2.2.6.2 Shannon-Wiener index of diversity
Shannon- Wiener provides information on both species richness and species
evenness, its value increases with the increase of number of species in the
community (Krebs, 1989; Maganga, 1999). Krebs (1989) explained as diversity
index value does not exceed 5.0, looking on studies carried out from various sources,
values of diversity are well described. Monela et al.(2005) came up with the results
within the range of 1.9-2.8 at Shinyanga communal and private forest, Bernado,
(2009) result fall within the range of 1.0-2.0 at Shinyanga state forest. Mean results
of Kaniki (2010) showed 2.7 at Manuo hill communal forest and 2.3 at Shirima
private forest, Rombo district.
Table 2: Indices of dominance (C) and diversity (H’) values
Forest
Location
Tenure
Regime
Vegetation
Type
H C Source
Shinyanga State Acacia open
bush land
0.99 -2.01 0.15 -0.41 Bernado,
(2009)
Shinyanga Private Acacia open
bush land
1.9 0.21 Bernado,
(2009)
Manuo Hill Communal
and Private
- 2.74 0.11 Kaniki,
(2010)
Kibele Forest
Reserve
State Coral rag
Forest
1.5 -1.8 0.3 – 0.4 Is-hak,
(2013)
Kiwengwa-
Pongwe
State Coral rag
Forest
0.83 – 1.74 -- Makame,
(2013)
Source: Is-hak, (2013).
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2.2.6.3 Simpson’s index of dominance
Species that have major contribution or influence on the community by size,
numbers or abundance, biomass or other parameters are known as dominants
Maganga, 1999). The disturbance of the dominants in the community will greatly
change the forests and the components of the forest (Maganga, 1999). Misra (1988)
described Simpson‟s index of dominance as the measure of probability that two
individuals randomly selected from a sample belonging to the same species. It is a
measure of distribution of individuals among species in a community. Its value
ranges from 0 to 1, the greater the value the lower the diversity (Misra, 1988). The
index shows the importance of each species in relation to the whole community. If
the dominance is more concentrated in one or few species the value is high and when
several species contribute equally to the community the index is low
(Maganga,1999).
2.2.7 Over-harvesting and Commercial of medicinal trees
Prominent Botanical Society has reported that about 50 % of the herbs and unique
plant species on earth may become extinct because of over-extraction and other
reasons like global climate change (Hussain et al., 2008). So, if herbs hold the key to
cure of HIV and cancers, we may lose them, which would be disastrous (Hussain et
al., 2008). Famous medicinal trees found in European countries the beautiful Yellow
gentian (Gentiana lutea); this herbal plant had been utilized for treating stomach
ache and other diseases (Primack, 2010). Approximately 1500 tons of dried roots are
used each year in many countries the plants been declining because of over-
harvesting which has become vulnerable in Portugal, Albania, Germany and some
countries becomes endangered (Primack, 2010).
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In India, had been known having 34 biodiversity hotspots of the world, is perhaps the
largest producer of medicinal plants in the world (Routledge, 2009). About 43,000
plant species recorded in India, 3,000 are known to possess medicinal properties
(Routledge, 2009). More than 900 medicinal plants are used in both classical and
oral health tradition including tribal medicines. Out of these 200 medicinal plants
species are largely extracted for diverse medicine and food products (Routledge,
2009).Thousands of licensed and unlicensed traditional medicine-manufacturing
units in India are collected from forests. Uncertain is increasing about the extinctions
of some species which are heavily extracted in the forest (Routledge, 2009).
Unsustainably high levels of exploitation are not a new problem, although the
problem has been escalated in regions with large urban areas and high levels of
urbanization since the 1960s (Shingu, 2005; McMullin, 2011).
2.2.8 Impact of over-harvesting medicinal Trees
One study has published report of some herbal plant of which has become extinct in
the wild in Ivory Coast which is called Monanthotaxis capea (Annonaceae) is an
aromatic leaves used for washing for cosmetic purposes (Ake-Assi, 1988). (U.S.
Forest Service, 2001), observed that Black Cohosh (Cimicifuga racemosa)
traditionally been used to treat a variety of conditions including colds, pain,
rheumatism, and menopause has been identified as at risk from over-harvesting and
habitat degradation. Studies conducted by Cunningham (et al., 2002) confirmed
Warburgia salutaris is vulnerable medicinal trees due to human induced habitat
degradation and over-exploitation. The species has been categorized as endangered
by IUCN Red list in 2012 (Cunningham et al., 2002) Damage assessments is
required for those species affected in trade and over-exploitation (Cunningham et al.,
2002).Species such as: Okoubaka aubrevillei, Garcinia afzelii, Garcinia epunctata,
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and Garcinia kola in Ghana, and Nigeria; Warburgia salutaris in Kenya, Tanzania
and Zimbabwe (Cunningham et al., 2002).Assessments is required to find out the
impact of over-extraction of some species namely Prunus africana and Pausinystalia
johimbe also bark harvesting in Cameroon and Madagascar, and fruit harvesting of
Griffonia simplicifolia, Voacanga thuoarsii and Voacanga africana for the
international pharmaceutical market (Cunningham et al., 2002).
2.2.9 Utilization of medicinal Trees
People in different parts collect medicinal plants for the health care and others collect
for business purposes. Khamis, (2011) reported different areas show that the most
parts of medicinal plants used are roots and leaves rather than other parts (Table
3).Probably roots and leaves have high concentration of therapeutic nutrients results
these parts to be more utilized.
The methods of collection differ in one area to another; this is due to the fact that
traditional knowledge of medicinal plants is mostly localized in a particular
community or tribe. The common methods of collection is uprooting, leaves picking,
debarking and so on, it depends on what part of medicinal plants is needed, Khamis ,
(2011).
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Table 3: Mostly used parts of medicinal plants
Percentage (%)
Parts used Magundi Makweli Bagamoyo Mgwashi Irente Maringo
Leaves 24.0 40.0 28.0 28.0 34.6 32.0
Roots 32.0 24.0 28.0 36.0 34.6 40.0
Barks 12.0 16.0 20.0 24.0 15.4 16.0
Rhizomes 4.0 0.0 4.0 4.0 0.0 0.0
Fruits and seeds 8.0 8.0 4.0 4.0 7.7 8.0
Whole plant 16.0 4.0 12.0 4.0 7.7 4.0
Stem and Latex 4.0 8.0 4.0 0.0 0.0 0.0
Source: Khamis, (2011).
The loss of plants usually occurs when roots, stem and bark are extracted and thus
used for preparation of medicinal trees. In this regards, Assefa and Abebe, (2014),
have reported that plant harvest involving roots, rhizomes, bulb, bark and stem have
a serious effects on the survival of the mother plant in its habitat. On the other hand,
analysis of plants documented shows that herbs share the largest proportion with 64
species (72%), followed by shrubs with 16 species (18%). Ermial Lulekal et al.
(2008) have found shrubs to make up the highest proportion of medicinal use
followed by herbs in their ethno-botanical research.
Nahonyo et al. (2002) Collected evidences that support many medicinal plants
species found in Jozani Forest in Zanzibar. More than 30 species of herbal plants
recorded were used by local community to cures various diseases using similar
medicinal plants found at Jozani forest reserve. Some of medicinal plants found in
Jozani reserve Zanzibar lists in Table 4.
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Table 4: Medicinal trees found at Jozani forest reserve
Medicinal trees. Parts used Diseases treated
Abrus precatorius, Roots, barks and
fruits
Asthma, skin diseases,
eye infections and
worms
Datura fastuosa,
Adansonia digitata
Soriendeia madagascarensi
Roots and barks Malaria, T.B, coughs,
reduce blood pressure,
worms. Rauvolfia mombasiana
Drypetes natalensis, Flueggia
virosa, Senna petersiana
Roots, barks and
leaves
Cold and fever ,
pregnancy conditions
and cough
Tacca leontopetaloides Roots Diarrhea
Rhu longipes, Leaves, roots and
barks
Gum and children fever
Solanum trepidan
, Bersama abyssinica
Punicum trichocladum,
Adansonia digitata.
Roots, barks and
leaves
Eyes
Eugenia jambolana Leaves Vomiting and flue
Senna petersiana Roots Flue
Antidesma venosum,
AnnonanSenegalensis
Roots and leaves Snake bite
Suregada zanzibarensis Leaves and roots Skin diseases and
Asthma
Senna petersiana Roots Hernia
Abrusprecatorius,Olea
woodiana, Sida spp.
Roots, fruits and
leaves
Coughing and fever
Adonsonia digitata Barks Small pox
Source: Nahonyo et al. (2002)
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2.2.10 Knowledge Gap
Harvesting of medicinal plants in many developing countries remain prominent
concern for plenty of wild medicinal species, without control on the exact quantity
harvested over time or the place of harvest may lead to decline and extinctions of
medicinal trees (Kuipers, 1995; Cunningham et al., 1993). Over-exploitation of
medicinal trees because of growing demand on local, national and international
markets (Cunningham 1993; Kuipers et al., 1997). Bark exploitation has caused
serious damage to wild populations of medicinal trees like Prunus africana,
including trees inside forests of high conservation value in Madagascar and
Cameroon (Cunningham et al., 2002).Zanzibar Island located off the coast of
mainland Tanzania, has a thriving culture of traditional medicine (MHZ, 2008).
Traditional medicine has experience a part of history in Zanzibar. Through the
review of theories and concepts explained about medicinal trees, there is inadequate
knowledge about diversity of medicinal trees in Unguja Central District of Zanzibar.
Therefore the current study was to investigate the impact of extraction of herbal
medicine on diversity of medicinal trees in Unguja selected villages of Marumbi and
Uroa in Central District of Zanzibar.
2.3 Conceptual Frame-work
Medicinal tree is the research topic which is assessed by measuring characteristics of
harvesting of medicinal trees diversity. Thus parameters of indices diversity of
medicinal trees and things influence the extraction of medicinal trees at Uroa and
Marumbi forests. There are many causes of extraction of medicinal trees such as
extraction for trade, extraction for self uses, extraction by traditional herbalist,
natural influence extraction and anthropogenic activities.
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Marumbi and Uroa have coral rag forests which consist of diversity of medicinal
trees that are decreasing due to extraction and anthropogenic activities. Traditional
healers, herbal traders and self-users are reported to extract medicinal resources of
the two villages which undermine medicinal trees of the two forests.
2.3.1 Independent variable
Independent variables are those that affect diversity of medicinal trees of the two
village‟s forests. The extraction of diversity of medicinal trees is involving
harvesting for sell, self-user and herbal healers. These extraction drivers of medicinal
trees changes indices of medicinal trees. The diversity indices such as Shannon-
wiener index of diversity and Simpson‟s index of dominance.
2.3.2 Intermediate variables
The intermediate variables are between independent and dependent. These include
natural influence like flood, diseases, drought and other human factors like
agriculture.
2.3.3 Dependent variable
The dependent variables are measured, and that is influenced or changed by the
independent variable. Medicinal trees diversity is dependent variable which is
affected by human activity specifically extraction medicinal trees diversity. Drivers
are economy, diseases faces society, cultural drivers, tourism and spiritual practice.
The result of the drivers is decreasing, declining and rarity of medicinal tree species.
It also includes change of species richness, evenness, abundance and final extinctions
of species. The effect of extraction of medicinal trees will affect economy, socially,
ecologically and environment of the natural forest of two villages.
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Figure 1: Conceptual frame-work
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CHAPTER THREE
3.0 Research methodology
3.1 Description of Study Area
The current study was conducted in two villages namely, Marumbi and Uroa Central
District of Unguja Island. The study was done in two selected villages which were
Marumbi and Uroa both villages are in Unguja Island. Marumbi and Uroa villages
are both located at the edge eastern region at Unguja Island about 25 km from
Zanzibar town (Figure 2). Both villages have coral rag forest which is the dominant
forest type in eastern Zanzibar, this is based on coral rag (ancient, reef) substrate,
characterized by shallow, alkaline top soils and showing a species composition
comparable to that of the Tanzanian coastal forests (Adrian et al., 2000).The two
forests villages is located between 390 25‟ 30‟ East to 390 28”20‟ while 60 9‟10‟ to
6012” south.
3.1.1 Economic activities
Uroa and Marumbi villages lie at coastal region eastern part of Unguja Island. People
in these villages are involved in farming and fishing activities. Human growth in the
villages are increased human needs and thus intensifies pressures on forest resources.
Due to limited arable land in the Islands, extensive clearance of natural forest occurs
(TGC, 2014).While the people at Marumbi village are most of them farmers and
other involved in fishing activities. Small part of Marumbi forest village is conserved
and large part is under pressure of human activities where the study has been under
taken.
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Source: Survey Section of Department of Forestry, Zanzibar
Figure 2: Map location of Uroa forest study area
3.1.2 Demography
According to NBS, (2013) census is the most recent census for which results have
been reported. The total population of Zanzibar is 1303,569 with an annual growth
rate of 2.8 percent. The population of, which was the largest city, is 223,033. Around
two thirds of the people 896721 lived on Unguja (Zanzibar Island), with the greatest
proportion settled in the densely populated west. The population of Pemba Island is
406848, (NBS, 2013).
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Marumbi village is located at coastal region close to Uroa village (Figure 3).
Source: Survey Section of Department of Forestry, Zanzibar
Figure 3: Location to show Marumbi forest study area
3.1.2.1 Central district Population
The total population of central District of Unguja is 76346 with males about 38538
and females 37808. The study was done in two villages including Uroa and
Marumbi. Table 5: displays population distribution in study area.
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Table 5: Human ppopulation as of 2013
Village Males (N) Females (N) Total
Uroa 1323 1290 2613
Marumbi 590 1,167 1757
Source: (NBS, 2013).
3.1.3 Climate
The main rainy season occurs between March and June. The short rains usually start
in October and ends in December. However, some inter-monsoonal precipitation
takes place. The average rainfall for the island is about 1500 mm per annum. The
highest temperature occurs during the short dry season with a maximum mean of
33°C in Unguja and 29°C in Pemba. The minimum temperatures for Unguja and
Pemba are 23.3°C and 21.1°C, respectively. In December to March is generally hot
and dry. While April and Mid of June is wet because of the long rains. July to
August is dry and breezy with little rainfall October - November is when the short
rains appear (Nahonyo et al., 2005).
3.1.4 Geology and Soils
Marumbi and Uroa are found 3km distance from each village. The topography is flat
terrain of about 20m to 30m above mean sea level (Nahonyo et al., 2005). The soil
lie within the shallow, acidic, infertile, rocky coral rag soils in the eastern part of the
Unguja which is named the darker "Kinongo" soils, derived from limestone parent
materials, are found towards east and south of the Island (Nahonyo et al., 2005). The
forest falls within coral rag terrain that lies from south of Unguja island pass through
Marumbi and Uroa forests to north of Unguja island (Nahonyo et al., 2002; Kombo
2010).
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3.1.5 Vegetation
The study areas are characterized by typical coast rag forest of indigenous plant
species vegetation commonly dominated by Suregada zanzibarensis, Encephalartos
spp., Euclea spp., Diospyros spp., Macphersonia spp., Eugenia spp., Mystroxylon
spp., Psychotria bibracteatum, Encephalartos spp., Macpharsonia spp., Ozoroa spp.,
Terminalia boivinii, Mimusopsis fruticosa, Calophyllum inophyllum, Polysphaeria
parvifolia, Diospyros kabuyeana, Ludia mauritiana, Combretum schumannii,
Dalbergia spp., Drypetes spp., Strychnos henningsii, Scorodophloeus fischeri,
Afzelia quanzensis, and Lecaniodiscus fraxinifolius (Nahonyo et al., 2002:Kombo et
al., 1998).
3.2 Research design
According to Kothari (2004) research design is the arrangement of condition for
collection and analysis of data in a manner that aims to combine relevant to research
purposes. The design of this study is completely randomized design (CRD) with
circular tree sampling plots (radius = m) were established systematically along
transect in both Uroa and Marumbi villages of Unguja Island. Inventory of medicinal
trees was counted by an ethno botanical survey among communities of neighboring
the two forests.
3.3 Sampling Frame and Sampling size
The sampling frame of this study has been expected to be 3780 for Marumbi and
Uroa villages. Sampling frame is an overall total number of people in the study site
(Kothari, 2004). Uroa had about 2613 population and 1,167 are from Marumbi
village. Respondents were interviewed and questioned on impact of extraction of
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herbal medicine on medicinal trees species diversity. The sample size was 44
respondents as computed from a formula by Kothari (2004):
2)(1 eN
Nn
.
3.4 Data collection methods
Both qualitative and quantitative data collection approaches were adopted. Primary
data was collected through interviews and semi structured questionnaires, matrix
ranking and field survey. Responses from the interviews were supplemented by
ethno-botanical survey of important medicinal tree species. Respondents like
traditional healers, herbalist and local peoples were source of information of primary
data. Ethno-botanical data was collected using semi-structured interviews and
medicinal trees were observed. Secondary data was collected as publications, reports
and relevant studies. Moreover, the existing publications, reports and other official
documents relating to the subject were used for secondary information
3.5 Data collection tools
3.5.1 Ethno-botanical Surveys
Ethno botanical surveys were collected using semi structured questionnaire and
interviews. Traditional healers and herbalist were randomly selected at Uroa and
Marumbi villages. According to Martin, (1995) Data collected on the use of
medicinal trees, plants parts used, collection techniques and diseases treated are
better method of ethno-botany survey. Information of threat of some medicinal trees
using interviews and field observation were provided. Total of 13 traditional healers
and 15 herbal sellers were selected as key informants and interviewed for detailed
information about extraction of medicinal trees.
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3.5.2 Questionnaires
A questionnaire is a research tool consisting of a series of questions and other
prompts for the purpose of gathering data from the study area (Oulu, 2002).Semi
structured questionnaires were used with forest officers, local community and herbal
sellers who use the forests to collect medicinal trees. These questions includes
identification of methods of extraction, magnitude extraction, prevailing diseases
treated, type of forest they used for collection and recording priority medicinal plants
and threats of medicinal trees due to over-harvesting.
3.5.3 Interviews
An interview is particularly useful for getting the data on participants behind
participants‟ experiences (White, 2002).The interview can provide in-depth
information around the topic, and be useful as follow-up for some respondents to
questionnaires. In this study, interview has been used to probe more information on
diversity of medicinal trees, priority herbal medicine used in the villages, rare
species, area of collection, extent of extraction and which effect would be emerged in
the community if certain medicinal trees become lost or rare. Also interviews have
helped to grasp information about the commercial of medicinal plants and the
threatened species. Traditional healers and Herbal sellers were centered part of the
current study interviews.
3.5.4 Matrix Ranking
Preference ranking technique was used to assess the degree of threatened species of
some selected medicinal trees (White, 2002). In this exercise, each informant was
asked to rank items based on degree of scarcity, availability and priority of medicinal
plants in the area) and their degree of importance. The most important or preferred
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species (in this case the most threatened medicinal plants) were assigned the highest
score, while the least preferred or abundant species was given the lowest. The
selected respondents were healers, herbal sellers, and local community and forest
officers. Then the degree is assessed according to ranking of species as threatened
(rarity), priority and plenty (availability).
3.5.5 Plant identification
The plant identification is very important for verification of medicinal trees species.
Botanist from Forest Department has been used to identify medicinal species and
their family. Using a botanist had compared and identified a specimen collected with
required specimen for accurate naming, such as flowers, fruits, seeds, roots and
normal leaves of the particular medicinal plants whose identities have been verified
by specialists over many years. Some samples of medicinal plants were collected and
many medicinal trees were identified by Botanist. Establishing plots in the field has
emphasized visual medicinal trees species and grasp knowledge of naming medicinal
trees by local names using traditional healers. Image of samples of some herbal trees
were taken in the field for further evidences.
3.5.6 Field Survey Method
Field method is essential to identify the habitats present in a study area, to record the
locations of habitats (Green et al., 1996) Also to identify each feature of location (e.
g. each habitat type). Field surveys were carried out at Uroa reserve forest and
Marumbi as community forests to identify diversity of medicinal trees, area of
collection and to assess the general extent of extraction of medicinal trees. The
quantitative objective in this study is answered using plots established in two forest
study area together with help from Forest department of Zanzibar. Diversity of
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herbal medicinal species was obtained and was verified to test their quantity and
accuracy.
3.5.7 Field Procedure
The current research was conducted in two village forests of Marumbi and Uroa
designed to conduct Medicinal trees inventory work excluding non-wood medicinal
trees. A total of 99 circular plots were established systematically in both forests.
Marumbi 64 plots and Uroa 35 plots, similarly radius of 11.28 m was preferred.
Marumbi had 365 m and Uroa 449 m which were the distance between plots. Sample
plots were identified by using Garmin GPS map. Field plot points in the two forests
were done by using GPS instrument Garmin extrex 29. All trees in the plots were
counted and identified. Each GPS point was recorded to correct missing data and
medicinal trees were recognized using healers excluding non-wood trees. TGC,
(2014) recorded forest area of Uroa has 706.3 ha as forest reserve and Marumbi has
853.2 ha forest community. The guideline of plot computation inventory work was
provided by Husch, (2002).Similar data were described by Malimbwi et al.(1994)
recorded in a data collection sheet (Appendix 4) for calculations to get stand
parameters that were used for identification and data analysis.
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Table 6: Tree sampling parameters for Marumbi and Uroa village forests,
Central district, Unguja
Parameter Marumbi Uroa
Forest area (ha) 853.2 706.3
Sampling intensity (i; %) 0.3 0.2
Transects (N) 6 11
Plots (N) 64 35
Plot radius (m) 11.28 11.28
Inter- plot distance (m) 365 449
Plot area (ha) 0.04 0.04
Sampled area (ha) 2.5 1.4
3.6 Diversity indices
According to Smith et al.(2001) Simpson index: The equation used to calculate
Simpson‟s index was D = ∑ (pi) 2. Where, D = Simpson index as pi = the proportion
of important value of the ith species (pi = ni / N, ni is the important value index of ith
species and N is the important value index of all the species). As D increases,
diversity decreases and Simpson‟s index is therefore usually expressed as 1 – D or 1/
D (Smith et al., 2001).
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Source: (2015) Survey Section of Department of Forestry, Zanzibar
Figure 4: Map plot layout of Uroa Forest reserve
Tree species diversity was computed using Shannon -Wiener index of diversity (H‟);
H‟=-∑si=1 pi ln (pi) (Kreb 1985).
Where: pi is the proportion of individuals belonging to the i-th species calculated as
pi = S/N; ln is logarithms (base), S is the number of individuals of one species, and
N is the total number of all individuals in the sample (Kreb, 1985). Simpson
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reciprocal starts with 1 as the lowest figure which represent few species, so the
higher the value the greater the diversity (Smith et al., 2001).
Source: (2015) Survey Section of Department of Forestry, Zanzibar
Figure 5: Map plot layout of Marumbi forest
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3.6.1 Tree species diversity
The data of tree species diversity include Simpson‟s Index of dominance (C) and
Shannon-Wiener Index of diversity (H), the data collected by establishing circular
plots of 0.04 ha, followed by identifying all trees within the plots and their number
was recorded for further processing and analysis.
3.6.2 Simpson’s Index of dominance
Data for Simpson‟s index of dominance adopted circular plots of 0.04 ha which were
established at distance of 365 m Marumbi forest along the transects that are set at
449 m for Uroa forest inter-transect distance, all trees within the plots counted and
identified for further processing and analysis. Shannon-Wiener index of diversity is
the same as for Simpson‟s index of dominance which is adopted circular plots of
0.04 ha and similar measures of inventory work of the current study.
3.7 Data Analysis
After collecting data in the study area, the data were checked against their answers in
order to ensure the consistency of information collected. After data refinement, the
analyses of the data were followed whereby the data from questionnaires were coded
into specific categories leading to the generation of simple statistics such as
frequencies and percentages. Collected data were summarized and analyzed using
Statistical Packages for Social Sciences (SPSS.17) and Microsoft Excel 2007.
Irrelevant data were discarded while missing gaps were filled through personnel
contact in the field. The data were then descriptively and quantitatively analyzed.
Frequency distribution tables and computation of proportions in percentage was used
in analyzing the socioeconomic variables for the respondents.
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3.7.1 Determination of tree indices of diversity
Tree indices of diversity include Simpson‟s index of dominance and Shannon index
of diversity.
3.7.2 Simpson’s index of dominance
Sampson‟s index of dominance was computed using Microsoft Excel spread sheet by
using formula: C = Σ (ni/N) 2
(Misra, 1988). Where C is the Index of dominance
Σ is the summation symbol
ni is the number of individual species sampled
N is the total number of all species in the sample.
3.7.3 Shannon-Wiener index of diversity
Shannon-Wiener index of diversity was computed using Microsoft Excel 2007
spread sheet by using formula: H‟ = -Σ (pi ln pi) (Kent, 1992).
Where: H‟ is the Shannon-Wiener index of diversity
Σ is the Summation sign
pi is the proportion of individual species
ln = natural logarithm
3.7.4 Data quality and control
Data quality control is crucial so as to make research perceived. To ensure this, two
aspects were observed namely; validity and reliability.
3.7.5 Validity
Validity is the process whereby an empirical measure adequately reflects the real
meaning of the concepts under consideration (Babbie, 1998).Validity in this research
achieved through proper identification of research problem, building a theoretical
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perspective on the medicinal trees use an impact of extraction of medicinal trees
diversity as well as using secondary information to guide the research processes. In
order to achieve the validity of the study, the scientific research process such as
identifying gap of knowledge clearly identified by designing the research problem
and undertaking the research process. Data of the study obtained are valid, since
resembles with the findings of other similar studies.
3.7.6 Reliability
Reliability is a matter of whether a particular technique is applied repeatedly to some
object would yield the same results each time (Babbie, 1998). Reliability of this
research study achieved by carefully constructing research tools like questionnaires,
matrix ranking and interviews as well as field survey and computation procedures
was done to ensure reliable data were recorded. Improper data and irrelevant
information were corrected through contact communication in order to put the
required information.
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CHAPTER FOUR
RESULTS PRESENTATION AND DISCUSSION OF THE FINDINGS
This chapter presents results, interpretation and analysis of the findings on effect of
extraction of herbal medicine on diversity of medicinal trees at villages of Marumbi
and Uroa central district of Unguja Island.
4.1 Results
Results are presented on medicinal tree species diversity and socio-demographic
characteristics, observing the effect of extraction of herbal medicine involved by
traditional healers with herbal sellers and the community. The findings also assess
the magnitude extraction of medicinal trees in the two villages.
4.1.1 Medicinal Trees species diversity
Total of 6051 Medicinal trees in 99 plots was sampled in two village forests.
Marumbi was 3920 Trees and 2201 trees at Uroa. Sum of 55 Medicinal trees species
were identified which belongs to 28 families. Table 7 lists the average measurements
of medicinal trees obtained in establishing plots.
Shannon wiener index of diversity, Simpson index were used to calculate medicinal
tree species diversity and abundance. The result at Uroa medicinal trees species
diversity was 3.106 while Marumbi medicinal trees species diversity was 2.89952.
Results on tree species diversity indices are indicated in Table 8.
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Table 7: The values of tree stocking and species richness
Forest Plots (N) Stems/ha Species Richness
Marumbi forest 64 1,530 39
Uroa forest 35 1,570 55
Table 8: Diversity indices of medicinal trees
Village forest D H E ( Evenness) Richness
Marumbi 0.108 - 0.287 1.44 – 2.89 0.830 - 0.952 39
Uroa 0.137 – 0.327 1.51 – 3.10 0.730 – 0.968 55
4.1.1.1 Forest tree inventory and medicinal trees assessment
A total number of 55 medicinal trees species and 28 families occurred on two
villages study forest plots. The density of each tree species was recorded by counting
the number of individuals and the frequency of each medicinal tree was recorded as
the percentage of plots that included the species. The estimations of medicinal plants
diversity and dominance were carried out using Species richness, Shannon–Wiener
diversity index (H),Simpson index of diversity (D) and Shannon evenness (E) with
Simpson index of dominance(C).Table 9 (a) and 9 (b): present results of diversity of
medicinal trees species which belong to 28 families at Uroa and Marumbi forests.
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Table 9 (a): Medicinal Trees species indigenous to Marumbi and Uroa Village
forests, central District, Unguja
SN Species Vernacular Family
1 Caesalpinia bonducella Mkomwe Caesalpinaceae
2 Pittosporum viridiflorum Mpande Pittosporaceae
3 Monanthotaxis fornicate Mchofu Annonaceae
4 Croton sylvaticus Msinduzi Euphobiaceae
5 Teclea simplicifolia Mcheza mwitu Rutaceae
6 Euclea natalensis Msiliza Ebenaceae
7 Vernonia zanzibarensis Mtumbaku mwitu Compositae
8 Drypetes natalensis Mjafari Euphpbiaceae
9 Polyphaeria porvifolia Mlapaa Rubiaceae
10 Flueggea virosa Mkwamba Phyllanthaceae
11 Eugnea spp. Mkaaga Myrtaceae
12 Euphorbia nyikae Mkweche Euphobiaceae
13 Mollotus oppositifolia Mtumbika Rubiaceae
14 Soriendeia madagascariensis Mpilipili doria Anacardiaceae
15 Macphersonia gracilis Mjoma Spindaceae
16 Suredada zanzibarensis Mdimsitu Euphobiaceae
17 Annona senegalensis Mtopetope Annonaceae
18 Mimusops obtusifolia Mnyovuo Sapotaceae
19 Sterculia Africana Muoza Sterculiaceae
20 Rapanea melanophloes Mkangara shamba Primulaceae
21 Rhus longipes Mchengele Anacardiaceae
22 Rhus natalensis Mkumba Anacardiaceae
23 Myternus mossanbicensis Mnusi Clastraceae
24 Fiscur spp. Mkuyu Moraceae
25 Sideroxylon inerme Mkandika Sapotaceae
26 Dodonea viscose Mkeneta dume Sapindaceae
27 Bersama abyssinica Muangakau Meliaceae
28 Dichrostrachys cinerea Mgunga Mimosaceae
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Table 9 (b): Medicinal Trees species indigenous to Marumbi and Uroa Village
forests, central District, Unguja (Continued)
SN Species Vernacular Family
29 Psidium punctuate Mkeneta jike Compositae
30 Trema orientalis Mpesu Canabaceae
31 Senna petersiana Mpingaume Caesalpinaceae
32 Turrea floribunda Mtamagoa Meliaceae
33 Croton psudopulchellus Mgeuka Euphobiaceae
34 Clausena anisata Muavikali Rutaceae
35 Carpodiptera Africana Muanga Sterculiaceae
36 Cussonia zimmerimanii Mtoto Araliaceae
37 Hoslundia opposita Mlashore Ebenaceae
38 Ozorora obavata Mngombe Anacardiaceae
39 Terminalia boivinii Mkunguni Combreatacae
40 `Leoniodiscus fraxinifolius Mbuyu mwaka Sapindaceae
41 Bridelia micrantha Mkaati Euphobiaceae
42 Psychotria bracteat Mkonge Rubaceae
43 Strychnos inncua Mtonga loganiaceae
44 Flacourtia indica Mgo Flacourtiaceae
45 Olea wodiana Mpweza/ mlimbo Oleaceae
46 Monodora grandidieri Mchofu dume Annonaceae
47 Euclea racemosa Mdaa Ebeneceae
48 Strychnos spinosa Mtongo Loganiaceae
49 Euphobia tirukali Mtofua macho Euphobiaceae
50 Fiscus expinosa Msasa/ Mchopaka Moraceae
51 Mystroxylon aethiopicum Kifugu Celastaceae
52 Toddalia asiatica Mnywa Rutaceae
53 Albizia adianthifolia Mkenge Fabaceae
54 Rawsonia lucida Mpera mwitu Flacourtiaceae
55 Ludia Mauritius Mchangachanga Flacourtiaceae
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4.1.1.2 Simpson’s index of dominance
The highest dominance average at Uroa was 0.037 while Marumbi was 0.025. Some
medicinal trees are more dominant at Marumbi and some at Uroa. The results show
that dominant species of medicinal trees species were similar in both forests patches,
these includes Polyphaeria parvifolia, Macphersonia gracilis, Euclea natalensis,
Suregada zanzibarensis, Euclea racemosa fiscuss spp. and Fluggea virosa. Some
medicinal trees are absent at Marumbi forest, example Croton sylvaticus, drypetes
natalensis, vernonia zanzibarensis and Teclea simplicifolia which were obtained at
Uroa forest reserve only. Table 10: present value of Simpson‟s index of dominance.
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Table 10: Dominant value (C) of medicinal trees
Species C
Marumbi Forest Uroa Forest
Polysphaeria porvifolia 0.18 0.14
Macphersonia gracilis 0.14 0.13
Euclea natalensis 0.101 0.11
Suregada zanzibarensis 0.065 0.067
Euclea racemosa 0.045 0.061
Fiscus spp. 0.050 0.036
Eugnia uniflora 0.040 0.029
Myternus mossambicensis 0.026 0.031
Flueggea virosa 0.027 0.066
Mollotus opporsitifolia 0.022 0.079
Clausena anisata 0.010 0.015
Bersama abyssinica 0.0066 0.022
Caesalpinia bonducella - 0.001
Croton psudochellus - 0.021
Croton sylvaticus - 0.00046
Flacourtia indica 0.0015 0.0084
Mean 0.05493 0.05105
Std 0.0522 0.0447
Source: Field data 2015
4.1.2 Socio-demographic analysis of respondents
Socio-demographic characteristics of the respondent that were investigated among
the selected respondent include gender and education. The total number of the
respondents involved in this study were 48 being twenty three (23) from Marumbi
and twenty five from (25) Uroa.
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4.1.2.1 Sex of respondents
The gender of respondents that were asked during this study about the use of
medicinal trees in two villages is presented in the Table 11. Results show that most
of respondents (62.5 %) asked were male and the remaining (37.5 %) were female.
Table 11: Sex of respondents
Gender Frequency (N) %
Male 30 62.5
Female 18 37.5
Total 48 100
4.1.2.2 Level of education
The levels of education of the respondents are shown in the Table 12. The results
indicate that 54.2 % have attained secondary education, about 18.8 % has informal
education, 16.7 % have attained primary education and 10.4 % completed tertiary
education. This imply that very few respondents completed tertiary education while
the herbalist and healers rely heavily on their informal knowledge when extract
medicinal trees.
Table 12: Level of education of the respondents
Level of Education Frequency Percent (%)
Informal education 9 18.8
Primary education 8 16.7
Secondary education 26 54.2
University 5 10.4
Source: Field data, 2015.
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4.1.3 Extent of extraction of medicinal trees
The study has exposed magnitude extraction of medicinal trees which is obtained
from herbal sellers, traditional healers and local community. Healers, herbalist and
herbal dealers perceive value of each medicinal tree and the knowledge which
determines frequency of collection.
4.1.3.1 Extraction and use of herbal medicine
The significance use of herbal medicine in the two communities is accepted, which
offer treatment of many ailments. Results of extraction and utilizing of herbal
medicine in the two villages are presented in Figure 6. Respondents indicate that self
users of medicinal trees entails herbal sellers 41.7 % (20) while local community
forms 27.1 % (13) and tradition anal healers are 31 % (15).
Figure 6: Extraction and use of medicinal trees
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4.1.3.2 Harvesting Medicinal trees parts
The harvesting of medicinal trees is involved all plants organs including roots,
flowers, fruits, seeds, and leaves, barks and resins. Harvesting medicinal trees parts
is presented in Figure 7. About 39.6 % (19) consider all parts of plant organs are
important for treatment of human ailments, total of 35.4 % (17) respondents prefer
seed, fruit and leaves during collection while 25 % (12) often collect barks and roots.
Harvesting sites of medicinal trees is taking place in community forest and forest
reserve of the two villages. Result shows both forest are used to harvest medicinal
trees. The findings denote that about 52 % of respondents use village forests to
harvest medicinal trees while 47.9 % use both reserve and village forests.
Figure 7: Harvesting parts of medicinal trees
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4.1.3.3 Frequency collection of medicinal trees
The collection of medicinal trees is often done depending on the need of the herbal
collectors. The result found that about 18.8% of the respondents collect medicinal
trees each week but 20.8% collect once per month while majority 60.4% collect any
time when they need medicine.
4.1.3.4 Collection of Priority medicinal trees
Some medicinal trees are more collected in the forest because they are better for
treating multiples of diseases. These are priority medicinal trees which were listed
and identified during matrix ranking and interviews with local peoples, Traditional
healers and herbal sellers. Majority of respondents mentioned Toddalia asiatica 72.9
% and Monanthotaxis fornicata 62.2 % while 45.8 % Pittosporum viridiflorum and
Teclea simplicifolia is 41.6 %.
Figure 8: Frequency collections of medicinal trees
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Figure 9: Priority medicinal trees
Plate 1: Priority medicinal trees (A) Monanthotaxis fornicata (B) Teclea
simplicifolia
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4.1.3.5 Medicinal trees parts used for trade
The plant parts used to treat human disease varied from species to species and from
disease to disease. Leaf, root, seed, bark and sap are widely used for treating human
diseases. Result shows roots were the most frequently used plant parts (66 %)
followed by barks and leaves (22.9 %) and the last are fruits, flower with seeds
which hold (12.5 %).
Figure 10: Medicinal trees parts used for trade
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Plate 2: Herbal shop sells (A) roots (B) barks of Pittosporum viridiflorum
Table 13: Threatened medicinal trees
Botanic name Local
name
Parts used Diseases treated
Pittosporum viridiflorum Mpande Bark, roots,
leaves
Stomach ache, skin
diseases, and anemia,
prevents abortion in
women.
Monanthotaxis fornicata Mchofu Roots, bark,
leaves
Fever, cough, stomach
aches, headaches.
Croton sylvaticus Msinduzi Bark, roots,
leaves,
seeds
Swelling hernia, Tb,
bleeding gum, abdominal
pain, uterus complication
Teclea simplicifolia Mchenza
mwitu
Bark, roots,
leave
Spiritual remedy, Malaria,
Premature baby, tooth
ache, cough, stomach ache
Vernonia zanzibarensis Mtumbaku
mwitu
Roots, bark,
leaves, seed
Spiritual remedy. Kidney
problem, hernia, fever,
influenza, dysmenorrhea.
Drypetes natalensis
Mjafari Bark, leaves,
flower, roots
Snake bite, Malaria, STD,
inflammation, ulcer,
diarrhea etc.
Source: Field data, 2015
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4.1.3.6 Threatened medicinal trees
Priority medicinal trees are threatened due to over-harvesting. This activity is
influencing the scarcity of PMTs. Results show that respondents mentioned drypetes
natalensis 68.7 % as the rarest followed by Croton sylvaticus 60 %, Vernonia
zanzibarensis 52 %, and Pittosprum viridiflorum 50 %, Teclea simplicifolia 39.5 %
and Monanthotaxis fornicata 14 %.The following Table 13: displays 6 medicinal
trees which are difficult to find them in forests zone due to over-harvesting.
4.1.4 Methodology of Harvesting Medicinal trees
The methods of exploitation of medicinal trees resources vary depending on the
quality of medicinal trees. The respondents use different methods of collection
medicinal trees in the community. For example 37.5 % of the respondents use
uprooting and 37.5 % use methods including uprooting, bark stripping and cutting
the trees. Among 16.6 % pick any plant organ depending on their treatments while
10.4% extract bark, seeds, leaves and fruits.
Table 14: Methods of collection medicinal trees
Methods of collection of Medicinal Trees Frequency (N) %
Uprooting 18 37.5
Extract fruits, seeds, leaves and bark 3 6.25
Pick any plant organ 9 18.75
Use all methods 18 37.5
Source: Field data, 2015
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Plate 3: Herbalists display uprooting method of MTs
4.1.4.2 Reasons for declining medicinal trees
Over-harvesting practiced by traditional healers, herbal sellers and the local
community lead to decline, rarity and losses of many species of medicinal trees.
About 39.6 % of respondents believed the availability of some medicinal trees is
difficult. Result of respondents show that 56% herbal sellers contributing to decline
medicinal tree while 23.8% traditional healers, 14.6% self users and 5.6% other
reasons including anthropogenic activities might be adding reasons of degrading
medicinal trees.
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Figure 11: Reasons for declining medicinal trees.
4.1.4.3 Effect of improper harvesting medicinal trees
Decline or losses of medicinal trees could bring adverse outcome to the surrounding
villages. Figure 12: present adverse outcome because of depleting medicinal trees.
Results from respondents denote 37.5 % believe economic effect could arise while
33.3 % health security effect could appear and 27.1 % ecological effect could result
but only 2.1 % believe other bad consequences could happen. These effects are about
to happen when certain medicinal trees become lost or decline.
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Figure 12: Effects of improper harvesting Medicinal trees
Plate 4: Show rarity medicinal trees (A) Croton sylvaticus (B) Drypetes
natalensis
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4.1.5 Conservation measures of medicinal trees
Sustainable harvesting of medicinal trees has been suggested so as to rescue the rich
medicinal tree diversity of the Unguja Island About 33.3 % of respondents
suggesting replanting (restoration) the medicinal trees will be useful measure to
prevent declining MTs. About 27.1 % of the respondents trust protection measures
of MTs would be better choice, while 20.8 % selected education measures could be
good idea of protecting MTs. The remaining 18.8 % of respondents believe
enforcing laws and against improper harvesting of MTs can be perfect measures for
protecting medicinal trees. Table 15: display conservation measures of medicinal
trees.
Table 15: Conservation measures of medicinal trees
Conservation measure Frequency(N) %
Protection medicinal trees 13 27.1
Enforce laws and policy 9 18.8
Replanting medicinal trees 16 33.3
Education 10 20.8
Total 48 100.0
Source: Field data, 2015
4.2 Discussion of the findings
This section discusses the findings of the study presented in section 4. The section is
divided into indices of diversity; extent extraction of medicinal trees and the findings
is discussed by interpretation of the presented results, reasoning the observations and
comparisons with other studies.
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4.2.1 Medicinal Tree species diversity
The study has shown that plant species used in traditional medicine belongs to
different habits ranging from herbs, climbers and shrubs to big tree species. But the
current study has selected woody plant communities (trees and shrubs) which are
more used by the traditional healers than the non-woody (climbers and herbs)
communities, similar study done by Hamisy etal. (2000).
Species diversity and evenness was recorded using Shannon-Weiner index and
Simpson reciprocal index of diversity (1/D). Uroa had greater diversity of medicinal
trees which was ranged 3.106 (H) and Marumbi had 2.89 (H).This because part of
Uroa forest is conserved and many medicinal trees are available but Marumbi forest
is exposed directly on human activities such as agriculture TGC, (2014).The highest
Simpson reciprocal index was 13.3 for Uroa and lowest was 12.0 for Marumbi
showing higher Medicinal trees diversity at Uroa than Marumbi. The comparison
result is correlated with Adnan, (2011) and Aggimarangsee et al.(2005).The
measures of Shannon Evenness (E) look close for both forest village which range
from 0.7308-0.968 for Uroa and 0.830-0.952 for Marumbi forest. This is because the
abundance of medicinal tree species is common in both villages except for Uroa has
some rare species of medicinal trees. This implies that Uroa forest has high richness
and diversity of MTs. However, Marumbi forest has high relative abundances of
each species but low diversity and richness. The evenness of MTs of the two villages
is very close since most of the medicinal trees species look similar. Medicinal trees
such as Pittosporum viridiflorum, Vernonia zanzibarensis, Teclea simplicifolia and
Croton sylvaticus are only found in Uroa forest in very few populations. Total of 22
plots were found within farming zone and justifies that the two forests are under
pressure of human activities which pose serious threat of the diversity medicinal
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trees existence. Marumbi forest is highly threatened due to the fact that all
anthropogenic activities are being done. This means that many species is being
cleared by collectors and human activities. The study result is related with Adnan et
al. (2009), Eleanor, (2002) and Shippmann et al. (2002); Cooper, (1985).
4.2.1.1 Index of dominance
Findings of index of dominance showed that the lowest average value of dominance
found at Marumbi was 0.0025 and Uroa was 0.037 forests and the highest value of
dominance medicinal trees species was Polysphaeria porvifolia 0.14 followed by
Macphersonia gracilis 0.13 and Euclea natalensis 0.11while the lowest value of
dominance found the rare medicinal trees species like Croton sylvaticus 0.0004 and
Caesalpinia bonducella 0.001.The value of index of dominance was similar to
Makame, (2013).Other studies, Monela at al. (2005); Bernado (2009); and Kaniki,
(2010),The greater the value the lower the dominance, it means few species
dominate the area, value ranges between 0 and 1 (Misra, 1988) Analysis showed that
medicinal tree species such as Suregada zanzibarensis, Rapanea melanosphores and
Macphersonia spp, have multiple uses such as firewood, medicine, fodder and
constructions, these species are at high risk according to Adrian et al.
(2008);Chhabra et al.(1987-1994).
4.3 Assessing extent of harvesting medicinal Trees.
Many people in Zanzibar extract herbal medicines due to increased prices and
shortages of drugs in the public sector. The demand for traditional medicine has been
increasing within the population (Ministry of Health Zanzibar, 2008). Study have
revealed that people engage in extraction of herbal medicine and other collect them
in villages forest and export them in Zanzibar town to the herbal shops. It is
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widespread among healers and community that usage of herbal medicine for the
treatment and alleviation of (chronic) diseases is accepted (Chhabra et al.,
1994).Over-harvesting for trade, traditional healers and self-user verify the intensity
or magnitude which leads decline of MTs. Similar result exposed by Khamis ,(2011);
Roberson ,(2008).
Result confirmed that the most used medicinal trees parts are roots followed by barks
and leaves. Roots, leaves and barks are frequently sold in Zanzibar which means that
an improper collection method of medicinal trees is done, the more the frequency of
roots collection the higher the decline and the rarity of diversity of medicinal trees.
Method of uprooting kills many medicinal trees species. Root excavation and bark
striping were the most harmful harvesting methods (Cunningham, 1991) For
example, in India; bark stripping is reported to threaten the existence of Rauvolfia
serpent (Akerere, 1991) and Hamisy et al. (2000).
4.4 Impact of harvesting of Medicinal trees
Herbalists perceive each part of medicinal plants posses‟ variety of medicinal
properties thus herbal collectors needs many parts including fruits, seeds, leaves,
bark, roots, flowers and stems. Herbal trees parts reported on local collection of
plants from the surrounding forests or farms, the wild forests of two villages of
Marumbi and Uroa. This result is also justified by Baylor, (2015). The invalid
harvesting of medicinal trees is depleting medicinal trees in the two villages.
Traditional healers acquire knowledge of remedy of medicinal plant which decides
what part of herbal plant is useful for his or her patients. According to Lange et al.
(1997) harvest of medicinal plants involving roots, rhizomes; bulb, bark and stem
which have a serious effect on the survival of the mother plant in its habitat. An
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effect of over-extraction of MTs is revealed in this study including economic effect,
health effect and ecological effects. Endashaw, (2007) cited threat of ecological
degradation, loss of indigenous knowledge and loss of cultural assets. An improper
collection of MTs keep susceptibility on species which varies in biological characters
such as different growth rates (slow growing vs. fast growing), reproductive systems,
(eg vegetative propagation; germination rates) and life forms (annual; perennial;
tree) Shippmann et al.(2002).The people may lose income when certain medicinal
trees disappear in the community. Example Croton sylvaticus and Drypetes
natalensis are classified endangered by IUCN (Nahonyo et al., 2002). Similar study
has mentioned that the increased demand for medicines has even led to local
extinction of certain medicinal trees such as Siphononchilus aethiopicus and
Warburgia salutatris outside the protected areas in KwaZulu-Natal in South Africa,
(Mander, 1997); Delvaux et al.(2009).
Healers expressed experience and comment on certain medicinal trees that may be
used the whole plant parts since the capacity of such plant on the treatment of the
illness is recognized. Giving example on Caesalpinia bonducella the plant seeds
treat dysmenorrhoea, malaria and trachoma while bark, leaves and roots can cure
fever with chest pain. Example of PMTs are used the whole plant parts because treat
multiples of ailments. Examples of priority medicinal trees under the study are
Pittosporum viridiflorum, Croton sylvaticus, and Toddalia asiatica and Vernonia
zanzibarensis. Over collection of some species for medicinal uses has resulted
decline of some medicinal trees in the village forests like Croton sylvaticus,
Caesalpinia bonducella, Pittosporum viridiflurm, Vernonia zanzibarensis, Teclea
simplicifolia, Drypetes natalensis and Mononthotaxis fornicate are both rarely seen
due to over-exploited for medicinal uses. Similar evidence founded by Nahonyo et
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al. (2002). Data from the field observed that priority and rare medicinal trees have
extremely declined and threatened to extinction.
4.4.1 Methods of harvesting diversity of medicinal trees
The local community finds easier to harvest the roots and the bark of the medicinal
trees. Medicinal trees are threatened and many respondents confirmed that uprooting
method is removing the entire roots during harvest which lead to the death of the
plants. This is common method of harvesting for herbal sellers, traditional healers
and herbalist. The methods has contributed to decline Vernonia zanzibarensis,
Drypetes natalensis and Croton sylvaticus since the harvester excavate the entire
roots and kills the trees. Evidences are given by (Nahonyo et al., 2002; Adrian et al.,
2008; and Nahonyo et al., 2005; Khamis, 2011; Eleanor, 2002) Similar study of
uprooting and bark striping were the most harmful harvesting methods
(Cunningham, 1991).For example, in India, bark stripping is reported to threaten the
existence of Rauvolfia serpent (Akerele, 1991.The study discovered that some
people are involved in the trade of herbal trees collection which are sold at town for
high cost. Among the medicinal trees affected in the trade are Caesalpinia
bonducella, Toddalia asiatica, Teclea simplicifolia, Vernonia zanzibarenisis, and
Mononthotoxis fornicata and Pittosporum viridiflorm. This report is confirmed by
(Baylor et al., 2015;Eleanor 2002; Chantal, 2015).
The demands of harvesting the medicinal trees are getting higher due to increasing
price of modern medicine. Compared to other studies suggested that over-
exploitation, land use change threatens many medicinal plant species in Africa
(Anyinam 1995; Giday et al., 2003; Alves and Rosa, 2007). Some Traditional
healers extensively extract roots of Teclea simplicifolia and bark of Pittosporum
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viridiflorum where the species of these medicinal trees are becoming too rare which
are obtained only in a few populations in the forest reserve of Uroa village. The loss
of medicinal plant resources can have serious consequences, as decreasing supplies
of wild medicinal plants affect the overall health security of people, especially in
Africa (Marshall, 1998). Moreover, herbal medicine provides a significant source of
income for rural people in developing countries. Therefore, a decreased availability
of medicinal plants can also impact local livelihoods (Augustino and Gillah, 2005;
McMillen, 2012; Chantal, 2015; Colebunders et al., 2003).
4.4.2 Collection medicinal trees for trade
Species such as Vernonia zanzibarensis, Toddalia asiatica and Teclea simplicifolia
are much affected by root excavation, so their populations have critically declined.
(Kombo et al., 2002);For example some studies of herbal medicine like Prunus
africana, a globally recognized treatment for prostate cancer, is now critically
endangered due to unsustainable harvesting for international sale (Cunningham,
1997; Stewart, 2003). For many species, the ecological impacts of harvesting are
unknown, and this lack of knowledge hinders the identification of sustainable
harvesting levels or methods (Grace et al., 2002; Ticktin 2004; Ghimire et al., 2005).
Lack of alternate income sources; push them to over-exploit natural resources of the
region. Improper collection methods threat many valuable medicinal herbs that are
becoming rare due to their utilization (Swe and Win, 2005).
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Plate 5: Improper collection of medicinal trees
4.5 Conservations measures of medicinal trees
Protecting medicinal trees are accepted by most respondents in this study,
Traditional healers, herbal sellers, and most local community in Zanzibar are familiar
with Traditional Unit (Bazara la Tiba Asili) (TU), which was established by
government in 2009, that run under Zanzibar Traditional and Alternative Medicine
Policy Act, 2008:1; Larson, 2008) .This policy guide the contribution of traditional
healers and assure regulation , register, monitor, and protect medicinal resources
(Meier zu Biesen, Dilger and Nienstedt, 2012;Baylor,2015).Over-collection of
species poses a significant threat to some commercially valuable wild species and to
their habitats as well (IUCN, 2007). In addition about 15,000 medicinal plant species
may be threatened with extinction worldwide from overharvesting (IUCN, 2007).
Studies show that restoration can improve the situation for the conservation of native
species of biodiversity (Kanowski et al., 2005; Lamb et al., 2005).
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CHAPTER FIVE
CONCLUSION, RECOMMENDATIONS AND AREAS FOR FURTHER
STUDY
5.1 Conclusion
The results of this study revealed diversity of medicinal trees exist in two village
forests and hence many people are involved in medicinal trees extraction. Majority
of respondent preferred using medicinal trees in the area. Both forests in two
village‟s people exploit herbal resources and trading in town. The result clarified the
data from plots and questionnaire, matrix ranking and interviews then found that
over-harvesting of medicinal trees is leading cause for decline and causing rarity of
diversity of medicinal trees in the area.
The current study has justified that anthropogenic activities is contributing and
eroding the medicinal trees in the surrounding forest zone. The forest is habitat for
diversity of medicinal trees but the anthropogenic activity is adding cause of forest
fragmentation which has kept medicinal trees in small population. Traditional healers
and herbal sellers clutch unsustainable methods of extraction of medicinal trees
which is upsetting and impede medicinal trees species. The method such as
uprooting the trees is always killing the medicinal trees, so this method gradually is
depleting the medical trees species. Majority of respondents recognize rare medicinal
trees and realize that some medicinal trees are declining or had become too rare.
Medicinal trees such as Drypetes natalensis, Vernonia zanzibarensis, Teclea
simplicifolia and Pittosporum viridiflorum are declining and have become too rare in
the study area. The respondents also identified the diversity of medicinal trees which
are priority MTs that cure many diseases and condition; similarly they also
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mentioned medicinal trees which are difficult and are threatened to extinction
although, many other are plenty available in the near surrounding forest.
The result of this study had exposed that respondent accepted that the losses or
decline of certain species of medicinal trees could bring an adverse effect in the area.
The adverse effect including health, environment, ecological effect, socio-cultural
effect and economic effects but also the findings of current study has observed
change of species richness, evenness, relative abundance and declining of priority of
medicinal trees.
5.2 Recommendations
From the current study, the following recommendations are suggested:
1. Traditional healers and herbal collectors including herbal sellers should be
given education on sustainable extraction of medicinal trees.The Forest
Department of Zanzibar is responsible for instructing the herbal collectors on
sustainability.
2. The medicinal trees remedy continues to be used for many people in the
study area but the medicinal trees species active ingredient is not well
investigated. So the government could provide intensive investigation of
medicinal trees so as to identify safety.
3. The forest of the two villages are still under pressure of deforestation so the
government should provide enough security for reserve forest like Uroa
reserve forest in which plenty of medicinal trees that are declining.
4. It has been realized that medicinal trees are source of income for the local
residence but over-exploitation of this resource could undermine their
income. It is recommended highly that the local people are required to
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perceive the existing of the medicinal trees in order to hold conservation
efforts on MTs.
5. The anthropogenic activities of the two forest is threatening existence of the
medicinal trees so it is recommended that the people be given alternative
source of income by government in order to let the natural forest grows for
future generation and only be used sustainably which will be better idea in
management of biological resources.
6. The demand for medicinal trees is getting large worldwide since many
companies have been benefited due to developing drugs using medicinal
trees. In such situation the government is required to conduct special research
project in medicinal trees so that to develop useful medical drugs that can be
used to improve government revenue.
7. The extracts of these plants should be further analyzed to isolate the specific
antibacterial principles in them.
5.3 Area for further study
1. Detail assessment of all medicinal plants and their well-being contribution to
the local community.
2. An experiment investigation of active ingredient of medicinal plants that
could be help to antibiotic-resistant diseases.
3. Extensive scientific investigation of better fighting diseases medicinal plants
that could be used to develop herbal drugs then to be sold in pharmacies.
4. Effect of invasive species on native medicinal plants.
5. Impact of improper harvesting of medicinal plants on biodiversity of selected
forest ecosystem.
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REFERENCES
Adnan, M. and Holscher, D. (2011), Medicinal plants in old-growth, degraded and
re-growth forests of NW Pakistan. – Forest Ecology and Management
261 (11): 2105-2114.
Adrian V.ELY, Amour B.Omar, Ali U. Basha, Said A .Fakihi, Robert Wild, (2000),
A participatory study of wood harvesting industry of Charawe and
Ukongoroni united republic of Tanzania. Working paper 2000,
UNESCO, (South-South Co-operation Programme), Paris (France)
Ake Assi, L. (1988), Rare species at risk of extinction Ivory coast, Monogr. Syst.
Bot. Missouri Bot. Gard., 25, 461 - 463
Akerele, O., Heywood, V. and Synge, H. (1991), Conservation of Medicinal Plants,
Cambridge University Press
Alves, R, Rosa I, (2007), Biodiversity, traditional medicine and public health: where
do they meet? Journal of Ethno biology and Ethno medicine 3, 14.
Andrews, E.L. (1997), A Humble Herb as Rival to Prozac, International Herald
Tribune, Paris.
Anyinam, C. (1995), Ecology and Ethnomedicine: Exploring links between current
environmental crisis and indigenous medical practices. Social Science
and Medicine, 40:321 – 329.
Arias, T.D., (1999), Glosario de Medicamentos: desarollo, evaluacio˜n y uso,
Washington: Organizacio˜n Panamricana de La Salud. Organizacio˜n
Mundial de La Salud, p. 171.
Assefa and Tesfaye Abebe, (2014), Ethno botanical study of wild medical trees and
Assegid shrub in Benna Tsemay District, South Ethiopia, Journal of
science and Development.
Astin, J.A., (1998), “A review of the incorporation of complementary and alternative
medicine by mainstream physicians. Arch Intern Med. 1998 Nov 23;158
(21):2303-10. Review.
Augustino, S., Gillah, P.R. (2005), Medicinal Plants in Urban Districts of Tanzania:
Plants, Gender Roles and Sustainable Use. Int. For. Rev. 7, 44–58.
Babbie, E. (1998), The Practice of Social Sciences Research 9th
Education,
Wadsworth.
Barnett, A. (2006), “The New Piracy in Africa,” Guardian Weekly (UK), September
28, 2006.
Page 90
74
Batugal, Pons A, Jayashree Kanniah, Lee Sok Young and Jeffrey T Oliver (eds).
(2004), Medicinal Plants Research in Asia, Volume 1: The Framework
and Project Work plans. International Plant Genetic Resources Institute
– Regional Office for Asia, the Pacific and Oceania (IPGRI-APO),
Malaysia.
Bausell, R.B, (2007), Snake Oil Science: The Truth About Complementary and
Alternative Medicine. Oxford University Press.
Baylor , (2015), Analysis of traditional medicine in Zanzibar, Resource conservation
and Public attitude towards the traditional and alternative medicine.
Independent Study Project (ISP) Collection. Paper 2050.http:// digital
collections. sit.edu/isp_collection/2050
Bernado, J. (2009), Forest cover and use changes under different tenure regimes: A
case of “ngitili”, Meatu District, Tanzania.
Brown, K. (2002), Innovations for conservation and development. The Geographical
Journal,Vol 168. pp 6-17.
Brown, T (1997), "Clearances and Clearings: Deforestation in Mesolithic/Neolithic
Britain" J Ethnopharmacol (1995), Traditional healers in Tanzania: the
perception of malaria and its causes.
C.L.Nahonyo, L.B. Mwansumbi, C.A. Msuyo, C.A.Masuo, T.B. Suya and C.
Shingwenda, (2005), Ngezi - Vumawimbi forest reserve biodiversity
inventory report. Department of Zoology and Marine Biology UDSM
Tanzania.
C.L.Nahonyo, L.B. Mwansumbi, S.Eliapenda, C.Msuya, C.Mwansasa, T.M.Suya,
B.O. Mponda and P. Kihaule, (2002), Jozani Chwaka Bay proposed
National Park biodiversity inventory report, Department of Zoology and
Marine Biology UDSM Tanzania.
Caroline Meirzu Bieseni, Hansjorg Dilger, Tanya Nienstedt, (2012), Bridging gaps
in health care healing, Traditional medicine and biomedical health care
sector in Zanzibar. Freie university Berlin Tanya Nienstedt, World
doctors
Chantal Posthouwer .,(2015), Medicinal Plants of Kariakoo Market, Dar es Salaam,
Tanzania, MSc specialization: Biology: Evolution, Biodiversity and
Conservation, Leiden University, Darwinweg 4, P.O. Box 9517, 2300
RA Leiden, The Netherlands.
Chhabra, S.C., R.L.A. Mahunnah and E.N. Mshiu (1987-1994), Plants Used in
Traditional Medicine in Eastern Tanzania. In: Journal of Ethno
pharmacology (21, 25, 28, 29, 33): 6 Pamphlets.
Page 91
75
Colebunders R, Dreezen C, Florence E, Pelgrom Y, Schrooten W. (2003), The use of
complementary and alternative medicine by persons with HIV infection
in Europe. Euro support Study Group. Int J STD AIDS. 2003
Oct;14(10):672-4
Cooper, K.H. (1985), The Conservation Status of Forests in Transvaal, Natal and
OFS, South Africa. Durban, Wildlife Society of South Africa.
Cunningham S,B (1990), Man and Medicine the exploitation and conservation of
Traditional Zulu Medicine. Hamburg, Mitheilungen aus dem Institut fur
Allegemeine Botanik
Cunningham, A.B, Mbenkum, F.T (1993), Sustainability of harvesting Prunus
Africana bark in Cameroon: a medicinal plant in international trade.
People and Plants Working Paper 2, Division of Ecological Sciences,
UNESCO: Paris, France.
Cunningham, A.B. (1988), An investigation of the herbal medicine trade in
Natal/KwaZulu. Investigational Report No. 29. Institute of Natural
Resources, Pietermaritzburg.
Cunningham, A.B. (1991), Conservation of medicinal plants. In Development of a
Conservation Policy on Commercially Exploited Medicinal Plants: A
Case Study from Southern Africa. Cambridge University Press,
Cambridge, UK.
Cunningham, A.B. (1997), An Africa-wide overview of medicinal plant harvesting,
conservation, and health care. In: Medicinal Plants for Forest
Conservation and Health Care. Food and Agriculture Organization of
the United Nations, Rome, 116–129.
Cunningham, A.B., (1993), African medicinal plants. Setting priorities at the
interface between conservation and primary healthcare People and Plant
Initiative Working paper 1, UNESCO, Paris, France.
Cunningham, A.B., Ayuk, E., Franzel, S., Duguma, B. and Asanga, C. (2002), An
economic evaluation of medicinal tree cultivation: Prunus africana in
Cameroon. People and Plant Initiative Working paper 10. UNESCO,
Paris, France.
DCCFF, (2003), Project Proposal for the Kiwengwa-Pongwe Forest Reserve
Conservation Project. Submitted for Global Conservation Fund. August
2003. The Revolutionary Government of Zanzibar, 12pp.
Delvaux, C., Sinsin, B., Darchambeau, F. and Van Damme, P. (2009),Recovery from
bark harvesting of 12 medicinal tree species in Benin, West Africa.
Journal of Applied Ecology, 46, 703-12.
Page 92
76
Eleanor Bailey, (2002), People and Traditional Medicine in Zanzibar, the reason for
their patterns of use. MES(Environment and development) Lancast
University.
Emily Roberson,(2008),Medicinal plants at risk, Nature pharmacy, our Treasure
chest, A native Plant conservation campaign report. Center for
Biological Diversity P.O. Box 710Tucson
Endashaw Bekele, (2007), Study on actual Situation of Medicinal Plants in Ethiopia,
Prepared for JAICAF (Japan Association for International
Collaboration of Agriculture and Forestry.
Ermias Lulekal, Ensermu, Kelbessa, Tamirat, Bekele and Haile Yineger (2008), An
Ethnobotanical study of medicinal plants in Mana Angetu District,
southeast Ethiopia. J. Ethnobiol and Ethnomedicine. 4 (10): licensee
Biomed.
Ernst, E ,(1998), "Harmless Herbs? A Review of the Recent Literature" (PDF). The
American Journal of Medicine 104 (2): 170–8.
Ernst, E. (2002),"A systematic review of systematic reviews of homeopathy". British
Journal of Clinical Pharmacology Garden, London.
FAO (1997), Medicinal Plants for Forest Conservation and Health Care, Global
Initiative for Traditional Systems (GIFTS) of Health, Food and
Agriculture Organization of the United Nations (FAO), Non-Wood
Forest Products No. 11, Rome.
Fennel, C.W.K, L, Lindsey,L,J.L,G Sparg,G.I.Stafford,EE.Elgorash,O.M.Grace and
J.Van Staden,(2004), Assessing African Medicinal plants for efficiency
and safety: Pharmacological screening and toxicology, Journal of
ethnopharmacology.205-217.
Geldenhuys, C.J., (2004), Bark harvesting for traditional medicine: from illegal
resource degradation to participatory management. Scandinavian
Journal of Forest Research.
Ghimire, S.K., McKey, D., Aumeeruddy-Thomas, Y., (2005),Conservation of
Himalayan medicinal plants: harvesting patterns and ecology of two
threatened species, Nardostachys grandiflora DC. and Neopicrorhiza
scrophulariiflora (Pennell) Hong. Biological Conservation 124, 463–475.
Giday, M., Asfaw, Z., Elmqvist, T.,Woldu, Z (2003), An ethno-botanical study of
medicinal plants used by the Zay people in Ethiopia. Journal of
Ethnopharmacology, 85:43–52.
Page 93
77
Grace N Njoroge, Isaac M Kaibui, Peter K Njenga and Peter O Odhiambo,(2010),
Utilisation of priority traditional medicinal plants and local people's
knowledge on their conservation status in arid lands of Kenya (Mwingi
District) Jomo Kenyatta University of Agriculture and technology, 6:22
doi:10.1186/1746-4269-6-22
Grace, O.M., Prendergast, H.D.V., van Staden, J., Jager, A.K. (2002), The status of
bark in South African traditional health care. South African Journal of
Botany 68, 21–30.
Green, E.P., Mumby, P.J., Edwards, A.J., and Clark, C.D, (1996), A review of remote
sensing for the assessment and management of tropical coastal
resources. Coastal Management, 24, 1–40.
Hamburger, M., Hostettmann, K., (1991), Bioactivity in plants; the link between
phytochemistry and medicine. Phytochemistry 30 (12), 3864–3874.
Hamilton, A. C., Cunningham, A., Byarugaba, D. and Kayanja, F. (2000),
Conservation in a region of political instability. Conservation Biology,
vol. 14, pp 1722-1725.
Hamilton, A.C. (2008), “Medicinal plants in conservation and development: case
studies and lessons learnt.”, Plantlife International, Salisbury, UK.
Hamilton, A.C., (2004), Medicinal plants, conservation and livelihoods. Biodiversity
and Conservation, 13, 1477-1517.
Hamisy, W. C.D., Mwaseba, I. E. Zilihona and S. T. Mwihomeke, (2000), Status and
Domestication of Potentials of Medicinal Plants in the Uluguru
Mountains, Tanzania, Sokoine University of Agriculture. Morogoro,
Tanzania.
Harrison, K. A.; Bol, R. and Bardgett, R. D. (2007), Preferences for uptake of
different nitrogen forms by co-existing plant species and soil microbes
in temperate grasslands. Ecology 88: 989–999.
Hasan SS, Ahmed SI, Bukhari NI, Loon WC. (2009),Use of complementary and
alternative medicine among patients with chronic diseases at outpatient
clinics.
Hoffman,D, (1990), Holistic herbal, Thorsons Great Britain.
Husain, S. Z., Malik, R. N., Javaid, M. and Bibi, S.(2008), Ethonobotanical
Properties and Uses of Medicinal Plants of Morgah Biodiversity Park,
Rawalpindi, Pakistan Plant Sciences Departmen Quaid-i-Azam
University, Islamabad
Husch, B.; Beer, W. T. and Kershaw, A. J. (2002),Forest Mensuration Fourth
Edition John Wiley and Sons, London 456pp.
Page 94
78
International Union Conservation Of Nature (IUCN), (2002), Medicinal Plant
Conservation Newsletter of the Medicinal Plant Specialist Group of the
IUCN Survival Commission, Vol. 8.
Is-hak B, (2013), Impact of Human activities on performance of Kibele Forest
reserve, Zanzibar, Dissertation for Award of MSc Degree University of
Dodoma.
IUCN (2012), IUCN Red List of Threatened Species, Version 2012.1,
<www.iucnredlist.org>
IUCN, (2007), Species Survival Commission Medicinal Plant Specialist Group.
“Why Conserve and Manage Medicinal Plants?” Web resource:
www.iucn.org/themes/ssc/sgs/mpsg/main/Why.html. retrieved in 2007).
IUCN. (2014), The IUCN Red List of Threatened Species. Version 2014.2. Available
at: www.iucnredlist.org. (Accessed: 24 July 2014
Kaniki, H. N (2010), The Roles of Forestland Tenure Regimes in Regulating Forest
Ecosystem Goods and Services in Rombo District, Tanzania. Thesis
submitted for MSc degree in Forestry of the Sokoine University of
Agriculture.
Kanowski, J., Catterall, C.P., Wardell-Johnson, G.W.( 2005), Consequences of broad
scale timber plantations for biodiversity in cleared rainforest landscapes
of tropical and subtropical Australia. Ecology and Management 208,
359–372.
Kennedy DO, Haskell CF, Mauri PL and Scholey AB (2007), Acute cognitive
effects of standardised Ginkgo biloba extract complexed with
phosphatidylserine, Hum Psychopharmacol. 2007 Jun;22(4):199-210
Kent, M. and Coker, P. (1992), Vegetation Description and Analysis: A practical
Approach. Ann Arbor, Belhaven Press, London. 363pp.
Khamis M S, (2011), Medicinal plants for medical care and plants diversity
conservation: case study of west Usambara Mountains –Tanga.
Kombo, Y. (2010), Zanzibar Forest Biodiversity Versus Energy Crisis and Climate
Change. Zanzibar. 24pp.
Kombo, Y.H and Kitwana, M.M (1998), Coral Rag Soil Fertility Improvement,
Forestry Technical paper No. 72, Commission for Natural Resources,
Zanzibar.
Kombo, Y.H., S. I. Hamdan, M.K. Makame, K.H. Madeweya, A.U. Basha, T.A.
Said. (2002), Wood Fuel Consumption Survey for The Zanzibar Islands.
Technical Paper Number 134. Department of Commercial Crops, Fruits
and Forestry
Page 95
79
Kothari,R.C, (2004), Research methodology methods and techniques 2nd Ed New
Delhi. New age international publishers.
Krebs, C. J. (1989), Ecological Methodology. Harper Collins Publishers, New York.
Krebs, Charles J. (1985), Ecology, the experimental analysis of distribution and
abundance, 3rd
edition. Harper and Row, New York.
Kuipers, S.E. (1995), Trade in medicinal plants. In Medicinal plants for
conservation and health care. Non-wood forest product 11. FAO, Roma,
Italy.
Kuipers, S.E. (1997), Trade in medicinal plants. In Medicinal plants for forest
conservation and healthcare. In Non-Wood Forest Products (eds. G.
Bordeker, K. Bhat, J. Burley, and P, Vantomme), FAO, Rome. pp 45-49.
Lamb, D., Erskine, P., Parrotta, J., (2005), Restoration of degraded tropical forest
landscapes. Science 310, 1628–1632.
Lange D, Schippmann U (1997), Trade survey of medicinal plants in Germany: a
contribution to international plant species conservation. Bundesamt für
Naturschutz, Bonn.
Larson, K. (2008), Where Humans and Spirits Meet. The Politics of Rituals and
Identified Spirits in Zanzibar. New York, Oxford: Berghahn.
Light, M.E., Sparg, S.G., Stafford, G.I. and van Staden, J. (2005), Riding the wave:
South Africa's contribution to ethnopharmacological research over the
last 25 years. Journal of Ethnopharmacology, 100(1-2), 127-30.
Maganga, S. L. S (1999), Fundamentals of Ecology, Tanzania Printing Services Ltd.
Makame, N. (2013), The effect of forest degradation on forest structure and carbon
stock in kiwengwa pongwe forest reserve, Zanzibar. Dissertation for
Award of MSc Degree of Sokoine University of Agriculture
Malimbwi, R. E; Solbeg, B; and Luoga, E (1994), Estimation of biomass and volume
in Miombo woodland at Kitulangalo forest reserve. Journal of Tropical
Forest Science. Vol. 7: 230 – 242.
Mander, M., J. Mander and C. Breen (1997), Promoting the cultivation of indigenous
plants for markets Experiences from KwaZulu-Natal, Domestication and
commercialization of non-timber forest products in agroforestry systems
Rome, FAO (Non-wood Forest Products).
Marshall, N.T., (1998), Searching for a Cure: Conservation of Medicinal Wildlife
Resources in East and Southern Africa. Cambridge: TRAFFIC
International.
Page 96
80
Martin, G. (1995), Ethno botany: a methods manual. Chapman and Hall, London;
pp. xx, 79, 61-65.
McMillen, H., (2012), Ethnobotanical Knowledge Transmission and Evolution: The
Case of Medicinal Markets in Tanga, Tanzania. Econ. Bot. 66, 121–131.
McMullin S. ,(2011), An assessment of the health, trade, economic and sustainability
aspects of medicinal tree and shrub products (MTSPs) in Kenya. PhD
Thesis in Rural Development. Dublin, Ireland: University College
Dublin.
Michael Wink, (2012), Medicinal plants: A source of anti-parasitic secondary
metabolites. Institute of pharmacy and Molecular Biotechnology,
Heidelberg University.
Ministry of Finance (2013), Newsletter of the Medicinal Plant Specialist Group of
the IUCN Survival Commission, Vol. 8. p.40.
Misonge J. , Wakori E, Kimondo J., Kisengi J, Waiganjo B, Mwambeo M, Gachukia
R, Muguku J, Moriasi A, Mungai G, and Nickson O,(2015), Assessment
of diversity and conservation status of plants at Mount Kenya University
Medicinal Botanical Garden, Thika sub-County, Kiambu County, Kenya,
Department of Pharmacognosy and Pharmaceutics, School of Pharmacy,
Mount Kenya University
Misra, K.C, (1988), Manual of plant ecology. 3rd
Ed. Oxford and IBH Publishing
Co. Pvt Ltd, New Delhi.
Monela, G. C; Chamshama, S. A. O; Mwaipopo, R, and Gamssa, D.M (2005), A
study on the Social, Economic and Environmental Impacts of Forest
Landscape Restoration in Shinyanga Region, Tanzania. IUCN Report.
Muchugi AN. (2007), Kenyatta University, Biochemistry and Biotechnology.
Population genetics and taxonomy of important medicinal tree species of
the genus Warburgia. PhD Thesis in Molecular Genetics. Nairobi,
Kenya. Kenyatta University.
Mugisha MK and Origa H O, (2005), Traditional herbal remedies used in the
management of sexual impotence and erectile dysfunction in western
Uganda.
N, Aggimarangsee, N, Sitasuwan and C, Trisonththi (2005), Diversity of Medicinal
plants Khao Lammuak in Prachuap khiri khan Province, Thailand.
National Bureau of Statistic (NBS) (2012), National population and housing census
Ng‟atigwa C, (1999), Indegenous Knowledge of Medicinal Trees and Priority for
domestication in Shinyanga, Tanzania.
Page 97
81
Nibret, E., Ashour, M., Rubanza, C. D. and Wink, M. (2010), Antitrypanosomal and
Cytotoxic Activities of some Tanzanian Medicinal plants, Institute für
Pharmazie und Molekulare Biotechnologie, Universität Heidelberg, Im
Neuenheimer Feld 364, 8 69120, Heidelberg, Germany.
Nkandu, Anne Kuria, Fabrice Pinard and Fergus Sinclair,(2015), Tree species
diversity and abundance in coffee farms adjacent to areas of different
disturbance histories in Mabira forest system, central Uganda,
International Journal of Biodiversity Science, Ecosystem Services and
Management, DOI: 10.1080/21513732.2015.1050607
Norhajar Eswani, Kamziah Abd Kudus, M. Nazre and A.G. Awang Noor (2010),
Medicinal Plant Diversity and Vegetation Analysis of Logged over Hill
Forest of Tekai Tembeling Forest Reserve, Jerantut, Pahang Faculty of
Forestry, University Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
Okigbo RN, Eme UE, Ogbogu S (2008), Biodiversity and conservation of medicinal
and aromatic plants in Africa. Biotechnology. Mol. Biol. Rev. 3(6): 127-
134.
Oulu, K. (2002), Online source, <en. Wikipedia.Org/wiki/Questionnaires>
University Library, Retrieved 03/09/2010.
Owuor B.O., Kamoga D., Kungu J., and Njoroge G.N. (2006), Some Medicinal Trees
and Shrubs of Eastern Africa for Sustainable Utilization and
Commercialization. Nairobi
Penso, G. (1980), WHO inventory of medicinal plants used in different countries. –
Geneva, Switzerland, WHO.
Primack, R.B (2010), Essentials of Conservation Biology, Fifth Edition, Sinauer
Associates, Inc,. Publishers, Massachusetts USA.
RGZ, (2008), Zanzibar Traditional and Alternative Medicine policy,Ministry of
Health and Social Welfare in Collaboration with World Health
Organization, Government press Zanzibar.
Routledge P, (2009), The use of herbal medicines by people with cancer: a
qualitative study, BioMed Central Ltd, DOI: 10.1186/1472-6882-9
Samson Gwali, Hillary Agaba, Paul Balitta, David Hafashimana, Joseph,(2011),
Assessment of plants diversity and ecological status of the coastal
Tanzania forests, A case study of Mafia Island „Coastal Forest Mosaic
Schippmann, U., Leaman, D.J. and Cunningham, (2002), Impact of cultivation and
gathering of medicinal plants on biodiversity: global trends and issues.
In: Biodiversity and the Ecosystem Approach in Agriculture, Forestry
and Fisheries. Food and Agriculture Organization (FAO), Rome.
Page 98
82
Schmincke KH (2003), Medicinal Plants for forest conservation and healthcare.
Non- Wood Forest Products 11, Food and Agriculture Organization of
the United Nations.
Shingu, G.K. (2005), Ownership and sustainable issues of botanical medicines,
Ethnobotany research and applications, 3, 17-23.
Silima, P. A. (2010), The Zanzibar National Forest Policy analysis, Final Report.
Smith, R.L. and T. M. Smith, (2001), Ecology and Field Biology, 6th
edition.
Addison Wesley Longman, San Francisco, 771 pages.
Soetan KO, (2008), Pharmacological and other beneficial effects of Ant nutritional
factors in Plants- A Review. Afr. J. Biotechnology. 7(25): 4713-4721.
Srivastava, R. (2000), Studying the information needs of medicinal plant
stakeholders in Europe. TRAFFIC Dispatches, Vol 15 ( 5). Cambridge,
UK.
Stewart, K.M., (2003), The African cherry (Prunus Africana): can lessons be learned
from an over exploited medicinal tree? Journal of Ethno pharmacology
89, 3–13.
Swai, G,Shirima, D., Makero, Emanuel, J, Yahaya. A., (2011), An assessment of
plants diversity and ecological status of the coastal Tanzania forests, A
case study of Mafia Island „Coastal Forest Mosaic, Department of
Biological Sciences (SUA),
Department of Forest Biology (SUA),
Forestry Training Institute (FTI), Forest and Beekeeping Division
Swe T, Win S. (2005), Herbal gardens and cultivation of medicinal plants in
Myanmar regional consultation on development of traditional medicine
in the South East Asia region, Department of Traditional Medicine,
Ministry of Health.
Tanya Pergola, Terrawatu, (2001), Changes in using and conserving Medicinal
Plants in Maasai, www.terrawatu.org/undp-gef_brief.htm ,(Viewed in
2003).
Terra Global Capital (TGC), (2014), HIMA (Hifadhi ya Misitu ya Asili ya jamii)
REDD+ Program, Zanzibar, Tanzania.
Ticktin, T, (2004), The ecological implications of harvesting non timber forest
products. Journal of Applied Ecology 41, 11–21.
U.S. Forest Service, (2001), Non-Timber Forest Product Fact Sheets, Web resource:
www.sfp.forprod.vt.edu/factsheets/factsheets.htm,(viewed in 2001).
UNESCO, (1996), Culture and Health, Orientation texts- World Decade for
Cultural Development Documents CLT/DEC. PRO-1996, Paris, France,
p. 29.
Page 99
83
Vallance P, and Smart TG, (2006), "The future of pharmacology". British Journal of
Pharmacology, Br J Pharmacol.;147 (Suppl 1):S304–S307.
Walter, K.S. and H.J.Gillett, (1998; 1997), IUCN Red List of threatened plants.
Gland, Switzerland, IUCN.
Wang, J., ( 2006), “Platensimycin is a selective FabF inhibitor with potent antibiotic
properties.” Nature 441, 358-361.
White, B. (2002), Writing your MBA Dissertation, Continuum, London.
WHO, (1992), Quality control methods for medicinal plant materials, Geneva.
WHO, (2000), General guidelines for methodologies on research and evaluation of
traditional medicine, World Health Organization,Geveva www.iucn.org/
themes/ssc/sgs/mpsg/main/Why.html.
WHO, IUCN and WWF, (1993), Guidelines on the conservation of medicinal plants.
– Gland and Geneva, Switzerland.
WHO., (2002), Traditional medicine strategy (2002-2006), - Retrieved from WHO
website, www.who.int/medicines/library/trm/trm_strat_eng.pdf (viewed
30.9.2002)
Williams, V.L., Balkwill, K. and Witkowski, E.T.F. (2000), Unraveling the
commercial market for medicinal plants and plant parts on the
Witwatersrand, South Africa. Economic Botany, 54(3), 310-27.
Williamson, E., Okpako, D.T., Evans, F.J. (1996), Selection, Preparation and
Pharmacological Evaluation of Plant Material, Wiley, Chichester
Wilson, E. O (2006), Threats to Global Biodiversity, (http//www.global change), site
visited on 29th September, 2012.
Zanzibar Ministry of Health and Social Welfare (2008), Zanzibar Traditional and
Alternative Medicine Policy Act No. 8: The Traditional and Alternative
Medicine (Code of Ethics, Conduct and Practice) Regulations. Ministry
of Health and Social Welfare.
Zhou, S.F.,Chen, X.W.; Sneed, K.B.; Pan, S.Y.; Cao, C.; Kanwar, J.R.; Chew, H.
(2012), Herb drug interactions and mechanistic and clinical
considerations. Curr. Drug Metab. 13, 640–651.
Page 100
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APPENDICES
Appendix 1: Diversity of medicinal trees in Unguja –Central District Zanzibar
INTERVIEWS FOR TRADITIONAL HEALERS
1. Do you use or sell herbal medicine for treating your patients?
2. Which forest do you find your herbal plants?
3. How many times do you collect herbal medicine in the forest per months?
4. What parts of herbal plants do you extract most often?
5. Which method do you use for gathering herbal trees in the forest?
6. The availability of herbal trees in the forest is difficult or easy?
7. Why some herbal trees are easy and some are difficult to find?
8. Do you find any herbal trees which are so rare to find in the forest?
6a) Yes ( ) No ( ) 6b) Why they are rare to find them?
9. Name most rare or difficult herbal trees in the natural forest of your village.
10. Name the herbal trees that are easily obtained in the natural forest.
11. Which medicinal trees parts are frequently sold by Herbal sellers?
12. How does it affect you as society when certain herbal trees become lost or
unavailable?
13. Mention conservation measures that might reduce destruction of herbal trees.
14. Name common herbal trees that are capable of treating number of diseases in
the villages.
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Appendix 2: Title: Diversity of medicinal trees in Unguja Central District
Zanzibar.
QUESTINNAIRE FOR HERBALIST AND COMMERCIAL HERBAL
TRADERS.
These questionnaires are supposed to be filled by Traditional Herbalists,
Commercial herbal traders and local peoples. Please fill the answers bellow
according to instructions after each question. Your answer is important and will be
treated confidential.
1. The village native Shehiya of………………………………………………..
2. District…………………………………………………………………………
3. Sex, Female………………………4.Male………………………………………
4. Level of your education between form 4 to 6 ( ), Bachelor ( ),
Other ( ) Put tick where appropriate
5. Do you extract, sell or use herbal Medicine? YES ( ) NO ( ).Select one,
put a tick.
6. How do you involve in the use of herbal medicine? 1. Collector and Traditional
herbalist ( ) 2.Herbal trader ( ) 3.Collector for self user ( ).
7. Which part of medicinal trees you collect or extract most often? 1.Bark and roots
( ) 2. Seeds, fruits and leaves ( ) 3.All parts ( ).
8. Where do you find your herbal plant? Local forest ( ), Forest Reserve ( )
both forest ( ).Select one put a tick.
9. Which method do you use for gathering herbal trees? 1. Uproot the tree and
extract roots ( )
2. Extract bark and leaves ( ) 3. Extract any part I need ( ) 4. All method ( )
10. How often do you collect the herbal trees in the forest? 1. Each week ( ), 2.
Each month ( ), 3. Any time when I need for self-use ( )
11. How is difficult to find the herbal trees species you need.
1. Difficult ( ), 2.Some herbal trees are so rare ( ), some herbs are easy
some are so difficult ( ).
12. Do you know herbal trees which are very rare that are better for treatment?
1. No ( ) 2. Yes ( ).
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13) Please name the native herbal Trees which are difficult to find in village natural
forest.
1………………………………………………………………………………
2………………………………………………………………………………
3………………………………………………………………………………
4………………………………………………………………………………
5………………………………………………………………………………
14) Why some herbal medicines are becoming rare or difficult to find:
1. Over-extraction ( ) 2.harvesting for sell ( ) 3. Harvest for personal use (
) 4. Others ( )
15. Name herbal trees which are easily available in natural village forest.
1…………………………………………………………………………………
2………………………………………………………………………………
3………………………………………………………………………………
16. Which medicinal trees parts are frequently sold by Herbal sellers?
1. Roots ( ) 2.Barks and leaves ( ) 3.Fruits, Seeds and Flowers ( )
17 What can we do for herbal medicines that are becoming rare in our village forest?
1. Conservation ( ) 2.Education ( ) 3. Formulate laws 4.Replanting herbal
trees ( )
18) Which problem that may happen when certain herbal plant become lost or rare in
our village forest?
1. Economic ( ) 2. Ecological ( ) 3 Health ( )
18. Name herbal trees that are common for treating more than one disease in the
natural forest (herbal medicine that are better than other known to treat several
diseases in the village).
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Appendix 3: Diversity of medicinal trees in Unguja Central District-Zanzibar
Questions in the form of ranking medicinal trees bellow are supposed to be filed by
Traditional healers, herbal traders and local peoples.
District…………………………..Native Shehia of……………………
1. The following bellow are some common medicinal trees that are seen to become
rare or difficult to find them in the village forests. Use tick (√) in the table bellow
to show level of difficult or rarity in corresponding with the medicinal tree.
Medicinal trees
species
Show level of rarity or difficult of the medicinal trees
than other by putting tick ( √) corresponding to the
specific medicinal trees bellow.
Degree of rarity scores
1. Drypetes
natalensis
2. Pittosporum
viridiflorum
3. Croton
sylvaticus
4.Veinonia
zanzibarensis
5.Monanthotaxi
s fornicata
6.Teclea
simplicifolia
7. Caesalpinia
bonducella
8.Clausena
anisata
9Turraea
floribunda
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The following bellow are some common and easily available medicinal trees that are
found in the village forests. Use tick (√) in the table bellow to show level of
availability and presence in corresponding with the medicinal tree.
Medicinal
trees species
Show level of availability or presence of the medicinal
trees than other by putting tick ( √ )
Degree of availability scores
1.Euclea
racemosa
2. Polysphaeria
parvifolia
3.Flueggea
virosa
4.Eugenia spp.
5.Mollotus
oppositifolius
6. Sorindeia
madagascarien
sis)
7. Suregada
zanzibariensis
8.Machersonia
gracilis
9.Mtamagoa
10.Flacourtia
indica
11.Ozorora
obovata
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89
3. The following bellow are some common medicinal trees that are frequently used
by Traditional healers, herbal sellers and community village. Use tick (√) in the
table bellow to show level of priority in corresponding with the medicinal tree.
Medicinal trees
species
Show level of Priority of the medicinal trees for
treatment than the other by putting tick ( √ )
Degree of priority scores
1. Drypetes
natalensis
2. Suregada
zanzibariensis
3. Pittosporum
viridiflorum
4.Crotonsylvati
cus
5. Teclea
simplicifolia
6. Vernonia
zanzibarensis
7. Toddalia
asiatica
8.Mononthotoxi
s fornicate
9.Turraea
floribunda
10.Cussonia
zimmerimanii
11. Croton
pseudochellus
12.Annona
senegalensis
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Appendix 4: Medicinal Trees Data Collection In Villages Forests.
Shehiya of ……………………………………………………….
Date……………………………………………………….............................................
District………………………………………………………………………………
No of
Plots
Local name of
Herbal trees
(Jina la miti ya
dawa za asili)
Tally No.
Frequency
GPS
X………………
Y………………
Everage
Height
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91
Appendix 5: Medicinal trees foud in sample plots.
Botanical name Local
name
Parts used Diseases treated
Euclea natalensis Msiliza Roots Constipation
Polysphaeria
porvifolia
Mlapaa Roots Stomach aches
Flueggea virosa Mkwamba Leaves /
roots
Cure chest pain
Promote fertility in women
Eugnea uniflora Mkaaga Roots /
leaves
Influenza, cough and skin
diseases.
Mollotus
opporsitifolia
Mtumbika Roots /
leaves
Keep pregnancy in good
condition.
Treat children fever
Soriendeia
madagascariensis
Mpilipili
doria
Roots / bark Treat T.B, worms,
Menstruation in women.
Macphersonia
gracilis
Mjoma Roots Treat erectile dysfunction
Suregada
zanzibarensis
Mdimsitu Leaves, roots Mosquito repellent,
Pressure, fever, abdominal
pain.
Annona
senegalensis
Mtopetope Fruits, bark,
leaves
Stomach aches, dysentery,
worms, pneumonia, cold.
Mimusops
obtusifolia
Mnyovuo Bark Wounds, sores
Sterculia
Africana
Muoza Bark , leaves Mental disorder, snake bite,
fever, influenza
Rapanea
melanophloes
Mkangara
shamba
Bark , leaves Spiritual remedy,
strengthen the heart.
Rhus longipes Mchengele Roots Malaria, fever.
Rhus natalensis Mkumba Roots Fitness for children,
wounds, dysentery, and
stomach aches.
Myternus Mnusi Leaves, roots Mixture with other herbs
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Botanical name Local
name
Parts used Diseases treated
mossambicensis treat ulcer,
Spiritual remedy
Fiscus spp. Mkuyu Leaves, bark Treat pain and skin diseases
Sideroxylon
inerme
Mkandika Cure broken born, fever,
spirits remedy.
Dodonea viscosa Mkeneta
dume
Bark, roots Digestive system disorder,
rheumatism
Bersama
abyssinica
Muangakau Bark, leaves,
roots
Worms, snake bites,
headaches, diarrhea.
Dichrostraschys
cinerea
Mgunga Leaves, roots Snake bites, wound, and
stomach aches.
Psidium
punctuate
Mkeneta
jike
Leaves Rashes
Trema orientalis Mpesu Leaves , bark Cough, asthma
Euphorbia nyikae Mkweche Bark, leave Mixture with other herbs
treats skin diseases and pest
crops. Paralysis
Senna pertesiana Mpingaume Constipation, stomach
aches
Turraea
floribunda
Mtamagoa Bark, leaves,
fruits
Throat, wounds, impotence
and absence
Croton
psudochellus
Mgeuka Roots, bark,
leaves
Cold, fever, asthma,
headaches and spiritual
remedy
Clausena anisata Muavikali Leaves and
Roots
Fever and cough
Control convulsion during
pregnancy.
Treat blood pressure and
worms.
Carpodiptera
Africana
Muanga Bark, root Treat eyes conditions
aphrodisiacs
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93
Botanical name Local
name
Parts used Diseases treated
Cussonia
zimmerimanii
Mpapai
mwitu
Roots, leaves Mental illness, bleeding for
children, fever, malaria,
gonorrhea.
Hoslundia
opposite
Mlashore Leaves Fever
Ozorora obovata Mgombe Roots Stomach ache and fever
Terminalia
boivinii
Mkunguni Bark Wound, sexual dysfunction
Caesalpinia
bonducella
Mkomwe Leaves,
roots, seeds
and bark
Malaria, stomach ache,
rheumatisms, trachoma,
anti-asthma.
Mystroxylon
aethiopicum
Kifugu Fruits, bark,
roots
Prevent miscarriage,
urinary infection, treatment
of multiples of stomach
condition. Anaemia
Flacourtia indica Mgo Fruits, bark,
roots
Spiritual diseases,
appetizing, digestive
discomfort, fever.
Euphobia tirukali Mtofua
macho
Roots, Seed Snake bite, Intestinal
parasites, aching bones.
Strychnos spinosa Mtongo Bark, fruits,
Roots
Impotence, Pregnancy
condition, fever, snake bite.
Bridelia
micrantha
Mkaati Bark, roots Stomach aches, aching
joints,
coughs
Strychnos innocua Mtonga Roots, bark,
fruits
Gonorrhea, snake bite,
facilitates child birth and
dysentery.
Monodora
grandidieri
Mchofu
dume
Seeds ,leaves Headaches and fever.
Toddalia asiatica Mnywa Roots ,bark Fever, cough, pregnancy
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Botanical name Local
name
Parts used Diseases treated
conditions and pain killer.
Albizia
adianthifolia
Mkenge Roots, bark Cure skin diseases, snake
bites, bronchitis and spirits.
Rawsonia lucida Mpera
mwitu
Roots, leaves Flue, cough, head aches
Ludia mauritiana Mchanga
changa
Roots, leaves Children fever, pregnancy
conditions
Source:Field data, 2015
