j our na l ho me pa g e: www.elsev ier .com/ locate / landurbplan
esearch Paper
ffect of tree planting design and tree species on human thermalomfort in the tropics
oyde Vieira de Abreu-Harbicha,∗, Lucila Chebel Labakia, Andreas Matzarakisb
School of Civil Engineering, Architecture and Urban Design, State University of Campinas, Rua Saturnino de Brito, 224, 13083-850 Campinas, BrazilFaculty of Environment and Natural Resource, Albert-Ludwigs-University Freiburg, Werthmannstrasse 10, D-79085 Freiburg, Germany
i g h l i g h t s
• Single and clusters of trees are quantified on a quantitative manner.• Thermal comfort conditions are strong influenced by solar radiation and wind.• Must appropriate tree for the improvement of thermal comfort conditions are Caesalpinia pluviosa.• Reduction of Tmrt can improve thermal comfort conditions about 16◦C (PET) during summer condition.
r t i c l e i n f o
rticle history:vailable online 12 March 2015
eywords:uman thermal comforthysiologically equivalent temperatureean radiant temperature
Trees behave in different ways on microclimate due to mainly distinct features of each species andplanting strategies especially in the tropics. This paper quantifies the daily and seasonal microclimatebehavior of various tree species with different planting design either individual or in clusters. This specificknowledge is an important step in the development of urban design guidelines based on the shading oftrees and climate adaptation in urban areas in the tropics. It focuses on human thermal comfort basedon the physiologically equivalent temperature (PET) for different species. Twelve species were analyzed:Handroanthus chrysotrichus (Mart. ex A.DC.) Mattos, Jacaranda mimosaefolia D. Don., Syzygium cuminiL., Mangifera indica L., Pinus palustris L., Pinus coulteri L.; Lafoensia glyptocarpa L., Caesalpinia pluviosa F.,Spathodea campanulata P. Beauv., Tipuana tipu F., Delonix indica F. and Senna siamea L. The results show
that shading of trees can influence significantly human thermal comfort expressed by (PET). The speciesC. pluviosa F. presents the best possibility in terms of PET because it can reduce between 12 and 16 ◦C forindividual trees cluster can reduce between 12.5 and 14.5 ◦C. Appropriate vegetation used for shadingpublic and private areas is essential to mitigate heat stress and can create better human thermal comfortespecially in cities. The results can be seen as a possibility of improvement of outdoor thermal comfortconditions and as an important step in order to achieve sustainability in cities.
. Introduction
An important characteristic of tropical cities is urban greeneryhat creates shading along streets and in residential areas and canssist in the development of adaptation possibilities against cli-
ate change. It also acts as a carbon sink, relative to the amount
f green coverage (Abreu-Harbich, Labaki, & Matzarakis 2013a,013b; Emmanuel, 2005; Emmanuel, Rosenlund, & Johansson,007; Grimmond, 2007; Lin, Matzarakis, & Hwang, 2010). The
characteristics of the various surfaces in urban spaces and theirbehavior with respect to incident solar radiation have seriousimpacts on the urban environment (Guderian, 2000). The studyof vegetation in the control of incident solar radiation, and asa regulator of urban climatic changes involves qualifying andquantifying the influence of trees on human thermal comfort(Abreu-Harbich, Labaki, & Matzarakis, 2012; Matzarakis, 2013;Matzarakis & Endler, 2010; Shashua-Bar, Pearlmutter, & Erell, 2009;Shashua-Bar, Potchter, Bitan, Boltansky, & Yaakov, 2010; Streiling &
Matzarakis, 2003; Yilmaz, Toy, Irmaka, & Yilmaz, 2007). Numerousstudies focusing on trees and their benefits in urban environmenthave been published (Bernatzky, 1979; Cardelino & Chameides,1990; Dimoudi & Nikolopoulou, 2003; Heisler, 1977; Herrington,1977; McPherson, Nowak, & Rowantree, 1994; Meyer & Bauermel,
1 pe and
1Somp2N2diBJS
iMotpctbtStaaHRSmm(tt2
fShc
iHLi
iraoGec
aefiaaasimtt
00 L.V. de Abreu-Harbich et al. / Landsca
982; Montague & Kjelgren, 1998; Oke, 1989; Santamouris, 2001;hashua-Bar & Hoffman, 2000; Shashua-Bar et al., 2010). Vari-us methodologies confirm that vegetation can influence urbanicroclimate, improve human thermal comfort, and decrease the
otential for health impairment of urban populations (Akbari,002; Akbari, Rosenfeld, Taha, & Gartland, 1996; Dimoudi &ikolopoulou, 2003; Mayer, Salovey, & Caruso, 2008; Santamouris,001; Streiling & Matzarakis, 2003). Arboreal species behave iniverse ways in outdoor spaces, especially in terms of differences
n shade, with previous studies quantifying these benefits (Bueno-artholomei & Labaki, 2003; Lin et al., 2010; Shahidan, Shariff,
Urban trees can modify air temperature, increase air humid-ty, reduce wind speed, and modify air pollutants (Streiling &
atzarakis, 2003). It has been confirmed that the positive effectsn the bioclimatic conditions of a city, the mean radiant tempera-ure (Tmrt) and the human biometeorological thermal index – thehysiologically equivalent temperature (PET), of single trees andlusters are distinct because of differences between areas withrees and without trees. Local air temperature can be influencedy green coverage and leaf area index (LAI), which are impor-ant arboreal characteristics (Tsutsumi, Ishii, & Katayama, 2003).ome studies confirm that specific features of species, like struc-ure and density of the treetop, size, shape and color of leaves, treege and growth, can influence the performance of solar radiationttenuated by canopy, air temperature and air humidity (Abreu-arbich et al., 2012; Bueno-Bartholomei & Labaki, 2003; Correa,uiz, Canton, & Lesino, 2012; Gulyás, Unger, & Matzarakis, 2006;cudo, 2002; Shashua-Bar et al., 2009). Tree canopies are able toodify to microclimatic environments because of reflection, trans-ission and absorption of solar radiation and control wind speed
Steven, Biscoe, Jaggard, & Paruntu, 1986). In tropical climates,he possibility of changing wind conditions and shade will modifyhe microclimate and improve human thermal comfort (Lin et al.,010).
In Brazil, it was recently concluded that outdoor thermal com-ort is closely related to urban tree management (Spangenberg,hinzato, Johansson, & Duarte, 2008). Various Brazilian researchersave used PET, but these indexes need to be adapted to the locallimate (Monteiro & Alucci, 2010).
Studies have shown that shade and increase wind speed canmprove human thermal comfort in tropical climates (Abreu-arbich et al., 2013a; Akbari & Rose, 2008; Akbari & Taha, 1992;in et al., 2010). Therefore, planting trees is a good solution formproving thermal comfort in tropical cities.
The shade cast by trees, and the amount of radiation filtered, isnfluenced by the form and density of the canopy. The amount ofadiation intercepted depends on the density of the twigs, branches,nd leaf cover. These elements influence the overall characteristicsf tree shape and density (Abreu-Harbich et al., 2012; Brown &illespie, 1995; Scudo, 2002). Tree shade qualities are also influ-nced by the individuality of trunks and of leaves, which should beonsidered (Abreu-Harbich et al., 2012; Shashua-Bar et al., 2010).
As an example, tree species in Brazil can attenuate solar radi-tion from 76.3 to 92.8% in the summer months (Abreu-Harbicht al., 2012; Bueno-Bartholomei & Labaki, 2003). These results con-rm that the structure of the crown, and the dimension, shapend color of leaves influence the levels of reduction in solar radi-tion. It is important to observe the vegetation parameters whichffect solar radiation and wind in relation to their thermal control
trategies, and their different green elements (Table 1). It is alsomportant to quantify the thermal conditions of trees with field
easurements, and to combine these results with the tree featureso improve green design. Accordingly, planting the right trees inhe cities can improve and adapt the cities to climate change.
Urban Planning 138 (2015) 99–109
Our aim was to quantify the daily and seasonal microclimatebehavior of various tree species in different planting configurations.Such knowledge is important in the development of urban designguidelines based on the shading of trees and climate adaptation inurban areas of the tropics. We have focused on thermal comfort ofhumans based on the PET for different tree species. We intend toquantify these affects by providing quantitative results, which canbe applied in tropical regions.
2. Methodology
2.1. Study area
Our study was conducted in Campinas (22◦48′57′′ S; 47◦03′33′′
W; 640 m elevation), in the southeast of Brazil. It is one of thelarger cities in the country, with 1.1 million inhabitants and avery high population density of 1300/km2 (Brazil, 2010). TheKöppen-Geiger climate classification of the city is subtropical(Cwa; Kottek, Grieser, Beck, Rudolf, & Rubel, 2006), with less rain-fall in winter, and rainy, warm-to-hot days in summer. Meanannual air temperature is 22.3 ◦C and annual rainfall 1411 mm.Rain is predominant from November to March, with dry peri-ods of 30–60 days in July and August. The summer period isfrom November to April, with average maximum temperaturesbetween 28.5 and 30.5 ◦C and minimum temperatures between11.3 and 13.8 ◦C. The warmest month is February, with an averagetemperature of 24.9 ◦C (maximum 30.0 ◦C and minimum 19.9 ◦C).The winter season is June, July and August, with maximum tem-peratures between 24.8 and 29.1 ◦C and minimum between 11.3and 13.8 ◦C. The coldest month is July, with an average temper-ature of 18.5 ◦C (maximum 24.8 ◦C and minimum 11.3 ◦C). Theprevalent wind direction is southeast, with a mean annual speedof 1.4 m/s. Annual sunshine duration is 2373 h, and the meandaily solar radiation is 4.9 kWh/m2. Weather variations in Camp-inas are caused by regional atmospheric circulation shifts anddiverse topography. There are tropical, equatorial continental,tropical Atlantic (the most common) and polar (especially polarAtlantic) systems, and these modify the regional climate (Nunes,1997).
2.2. Sites and observations
The scales adopted in field measurement for this researchwere instantaneous and microclimatic, which allowed for assessingweather conditions and not climate. However, the “in loco” cli-mate, mainly within 1 km, was influenced by local environmentalparameters (solar radiation, air temperature, relative humidity andwind speed), and by macroclimatic and mesoclimatic conditions. Instudies concerned with qualifying and quantifying trees and theirbenefits at the micro scale, similar surrounding conditions shouldbe considered: no shade from buildings or other trees; uniformityof conditions around trees related to topography, lack of pavementand buildings nearby; standardization of the surface at the measur-ing points; and time of exposure, with few or no clouds. The criteriafor the choice of species to be studied were those most used in treeplanting programs of the Campinas city government. Trees wererequired to meet the following conditions: mature; their physi-cal characteristics were representative of their species; they werelocated in areas suitable for measurement; specifically unshadedby nearby trees or buildings; accessible topography and sufficient
area for equipment around the species; and no interference bypassers. The large gap of study different trees species is becausethey behave in different ways in microclimate. As well, it is neces-sary to consider the biodiversity for sustainability of urban greenon cities.
L.V. de Abreu-Harbich et al. / Landscape and Urban Planning 138 (2015) 99–109 101
Table 1Thermal control based in trees features.
es
•
•
•
cao
Fig. 1 lists the date of measurements, and the tree species forach site in the urban area of Campinas. Twelve species wereelected and grouped accordingly:
Single trees; Handroanthus chrysotrichus (Mart. ex A. DC.) Mattos,Jacaranda mimosaefolia D. Don., Syzygium cumini L., M. indica L.,Pinus palustris L., Pinus coulteri L.Single trees and clusters; Lafoensia glyptocarpa L., Caesalpinia plu-viosa F., Spathodea campanulata P. Beauv., Tipuana tipu F.Clusters; Delonix indica F. and Senna siamea L.
In supplementary material, extra tables show individual andlustered trees, along with characteristics such as crown, trunknd leaf. All measurement fields were situated in the urban areaf Campinas.
2.3. Measurement
For each individual tree and tree clusters, air temperature andhumidity, wind speed, and global radiation were collected for in theshade and in the sun during summer and winter periods between2007 and 2010. The sampling interval was 10 min every hour overa period from 6:00 AM to 6:00 PM Air temperature and humiditydata were collected with a Testo data logger, model 175-1. Twotripods were fixed in the shadow and in the sun. Wind speed datawere collected at a fixed site with a Testo anemometer, model0635-1549, connected to a multifunction recorder, model 445. The
sensors were positioned at a height of 1.1 m. All recordings wereprotected from solar radiation using special shelters designed foroutdoor measurements (Fig. 2).
eneath tree crowns and greenhouses. The spectral response corre-ponded to visible and near infrared radiation (350–2500 nm). Forndividual and clusters trees, one of the solarimeters was positionedn the middle of the tree shadow, while the second was positionedn sunlight.
.4. Methods and analyses
Modern human biometeorological methods use the energy bal-nce of the body (Höppe, 1993, 1999) to extract thermal indices forescribing effects of the thermal environment on humans (Mayer,993; VDI, 1998). For this study, we used values of meteorologicalata obtained every minute in the 10-min sampling time to calcu-
ate PET (Mayer & Höppe, 1987). To quantify the thermal comfortrovided by shade of trees, meteorological data (air temperature,ir humidity, wind speed and global radiation) collected from fieldeasurements were used to calculate PET with the assistance of
ayMan software (Matzarakis, Rutz, & Mayer, 2007, 2010). PETstimation was dependent on atmospheric influences, primarilylouds and other meteorological variables such as vapor pres-ure or particles. Tree morphologies acting as obstacles were alsoncluded. The primary input parameters to RayMan in the study
ere air temperature, air humidity, wind speed, and total solaradiation. The comfortable range that has been used is the Euro-ean one (Matzarakis & Mayer, 1996) in combination of the tropicalroduced/adjusted for Taiwan by Lin and Matzarakis (2008). Foruropean, the range of thermal comfort is between 18–23 ◦C and
or tropical 26–30 ◦C, and for extreme heat stress, higher than 41r 42 ◦C.
The attenuation of solar radiation was dependent on tree fea-ures such as the density of the twigs and branches, and leaf cover.he percentage of radiation attenuated by each tree, or cluster
and clusters.
of trees, was obtained by the method of Bueno-Bartholomei andLabaki (2003), where measurements of solar radiation in the shadeand in the sunlight were made simultaneously, in accordance withthe expression:
AT = Ssun − Ssh
Ssun× 100 (1)
For the time interval considered, AT is solar radiation attenu-ation (%), Ssun is the area (kWh/m2) for the total incident energycollected by the solarimeter in sunlight, and Ssh is the area(kWh/m2) for the total incident energy in the shade.
The plant area index (PAI) describes the amount of foliage whenreferring to all light-blocking elements (stems, twigs, leaves, etc.),while the leaf area index (LAI) accounts only for leaves (Holst et al.,2004; Nackaerts, Coppin, Muys, & Hermy, 2000; Neumann, Hartog,& Shaw, 1989). Hemispherical photography (“fish-eye”) in orthog-onal projections was used for specific points below canopies foreach individual tree, and clusters of trees. These pictures look forsun gaps in the canopy layer where direct or diffuse radiation is ableto reach the ground (Abreu-Harbich et al., 2012; Tsutsumi et al.,2003). To obtain the PAI of each analyzed tree, the Sky View Fac-tor (SVF) is calculated based on fish-eye pictures using RayMan Prosoftware, where the sky area is replaced by the area of branchesand green leaves.
2.5. Applied model
The RayMan model was applied to analyze the long-termchanges in thermal bioclimate caused by differences in tree shad-ing. RayMan allows the calculation of Tmrt, which is used to calculate
thermal bioclimatic indices, or PET. Tri-dimensional models of veg-etation were designed based on features of the studied trees, andincluded height, crown radius, trunk length and trunk diameter. Inaddition, the SVF of each individual tree, and cluster of trees, wasincluded in the simulation.
L.V. de Abreu-Harbich et al. / Landscape and Urban Planning 138 (2015) 99–109 103
For the quantitation of thermal comfort provided by treeanopies during different seasons, daily data results for air tem-erature (Ta) in summer and winter are shown in Figs. 3 and 4,espectively. Daily data results for PET in summer and winter areresented in Figs. 5 and 6, respectively.
Figs. 3–6 show the differences in temperature between sunlightnd shade from 6:00 AM to 6:00 PM. The cooling effects of treehading were more evident from 10:00 AM to 2:00 PM compared
ith those in the early morning and evening.
In the summer, the air temperature in direct sunlight and shadeor individual trees showed minor differences. The air tempera-ure for tree clusters however exhibited distinct patterns (Fig. 3).ndividual trees such as Handroanthus chrysotrichus, S. cumini, C.
ents equipment.
pluviosa, T. tipu reduced the air temperature by 0.9–2.8 ◦C between10:00 AM and 2:00 PM. Individual S. cumini exhibited the best shadebehavior, with 2.8 ◦C of cooling in the shade during this period. Clus-ters of C. pluviosa or T. tipu reduced the air temperature by 0.7–2 ◦Cduring the same period.
In the winter, air temperature reduction results differed (Fig. 4).The air temperature in the shade, or in direct sunlight, for indi-vidual trees (Handroanthus chrysotrichus, P. palustris, P. coulteri, L.glyptocarpa, M. indica and S. campanulata) was not significantlydifferent. For S. cumini and C. pluviosa, the air temperature wasreduce by 1.9–2.6 ◦C from 10:00 AM to 2:00 PM. For clusters oftrees (C. pluviosa, S. campanulata and D. indica), the air tempera-ture was reduced by 0.1–2.4 ◦C from 10:00 AM to 2:00 PM overthe same period. C. pluviosa exhibited the best cooling effects,whether individual or in clusters. With respect to individual treesof this species, the air temperature was reduced by 2.2–2.7 ◦C in theshade during the warmest daylight hours; a cluster of these treesreduced the air temperature until 2.0 ◦C in the shade over the sameperiod.
PET values observed for summer (Fig. 5) showed that the shadecast by individual trees, such as Handroanthus chrysotrichus, S.cumini, C. pluviosa, and T. tipu, reduced temperatures by as much as16 ◦C. Shading from C. pluviosa and T. tipu tree clusters reduced the
air temperature by 11.2–14.4 ◦C from 10:00 AM to 2:00 PM. C. plu-viosa exhibited the best effects with respect to improving thermalcomfort. An individual tree of this species reduced air temperatureby 12–16 ◦C during daylight hours, while a cluster of these treesreduced air temperature by 12–14.4 ◦C.
104 L.V. de Abreu-Harbich et al. / Landscape and Urban Planning 138 (2015) 99–109
Fig. 3. Diurnal courses of air temperatures during the summer.
Fig. 4. Diurnal courses of air temperatures during the winter.
Fig. 5. Diurnal courses of physiologically equivalent temperature (PET) (◦C) during the summer.
L.V. de Abreu-Harbich et al. / Landscape and Urban Planning 138 (2015) 99–109 105
ivalen
Mwr1owpbai
tsp2ftcs(
pamabs
watcsa
pcrTet
Fig. 6. Diurnal courses of physiologically equ
The PET values for winter (Fig. 6) show that individual S. cumini,. indica, C. pluviosa and L. glyptocarpa provided the best resultsith respect to improvements in thermal comfort. These trees
esulted in a reduction of air temperature of 7.4–17.5 ◦C from0:00 AM to 2:00 PM. Individual Handroanthus chrysotrichus with-ut leaves exhibited the worst results in terms of cooling effects,ith the air temperature reduced by only 0.6–1.1 ◦C over the sameeriod. A cluster of C. pluviosa and L. glyptocarpa trees had theest cooling effects, with their shading reducing the air temper-ture by 7.8–14.4 ◦C. Clusters of other tree species did not result inmprovements for thermal comfort.
A comparison of the summer and winter PET results showed thathe cooling effects of trees, either individual or in clusters, in theummer were greater than in the winter (Table 2). Using air tem-erature as factors the differences between sun and shade are less.8 ◦C in summer. For PET the differences are much higher rangingrom 1 up to 16 ◦C. For individual trees, the differences are higherhan for clusters because of the effect of wind on PET. This behavioran be explained by the phenology of each species. We have pre-ented the attenuated solar radiation over the year, along with PAIFig. 7).
For individual trees, the PAI results for the coniferous species P.alustris and P. coulteri, were 47 and 34% respectively. These treesre characterized by a pyramidal crown, a narrow canopy, and aoderate area of sunny spots with 53 and 66% SVF for P. palustris
nd P. coulteri, respectively. The cooling effects can be explainedy solar radiation attenuated by the crown (79.7 and 83.8% duringummer; 69.8 and 78.3% during winter).
The PAI results for the perennial species S. cumini and M. indicaere 87.8 and 85%, respectively. These trees are characterized by
dense canopy, a plagiotropic trunk, and produce relatively largeree coverage. This leads to high cooling effects in terms of thermalomfort, especially during the winter. The attenuation results forolar radiation during the summer were 87.2 and 89.2%, and 89.1nd 88.6% during winter for S. cumini and M. indica, respectively.
Semi-deciduous species as J. mimosaefolia, L. glyptocarpa and C.luviosa can be characterized by their plagiotropic trunk, distinct
anopies, and considerable variation in PAI (26.9, 74.8, and 92.3%espectively), which can vary from sparse to dense during the year.hese native trees have a medium–large coverage and high coolingffects in terms of thermal comfort, especially during summer, dueo the quality of shading and access by wind. As an example, C.
t temperature (PET) (◦C) during the winter.
pluviosa can attenuate solar radiation by 83.8% in summer, but only69.5% during winter.
Deciduous species such as Handroanthus chrysotrichus, S. cam-panulata and T. tipu are characterized by variation of leaves inthe crown over a year. Native Handroanthus chrysotrichus, with anorthotropic sympodial trunk, has a PAI of 47.7% and attenuation ofsolar radiation is 82.8% in summer and 46.4% in winter. When leaf-less, this value drops to 51.4%. Exotic species (S. campanulata and T.tipu) are characterized by plagiotropic trunks, with PAIs of 78.1 and72.2%, respectively. Attenuation of solar radiation during summerwas 76.3%, and over winter this was 55%.
For clusters of trees, the PAI results for C. pluviosa, L. glyptocarpa,S. campanulata, T. tipu, D. indica and S. siamea were 99.3, 65.7, 77.5,98.8 and 91.3%, respectively. During the summer, the results of solarradiation attenuation for C. pluviosa, T. tipu, D. indica and S. siameawere 94.8, 80.2, 73.5 and 89.2%, respectively. During winter, solarradiation attenuation results for C. pluviosa, L. glyptocarpa, S. cam-panulata and D. indica were 92.5, 76, 82.4, and 72.3%, respectively.Clusters of C. pluviosa had the best cooling effects for thermal com-fort. This can be explained by specific features of this species: theyare large trees with maximal coverage due to their height; theyhave plagiotropic trunks; and small bipinate leaves. In addition,the distance between the trees was proportional to the diameterof the crown (10 m × 10 m), along with the number of trees in thecluster (n = 20), and the linear formation of the cluster contributedto our findings.
4. Estimating cooling effects based on trees features
The tridimensional model was based on tree features includ-ing height, crown radius, trunk length and diameter, and outdoordisposition. Meteorological data from 2003 to 2010 were used toquantify the contribution of trees’ shade on built-up spaces usingPET.
The results (Fig. 8) show that individual trees as M. indica, S.campanulata, L. glyptocarpa, S. cumini, C. pluviosa provided the bestresults with respect to improvements in thermal comfort. These
trees resulted in a reduction of air temperature of 5.5–7.4 ◦C from10:00 AM to 2:00 PM. Individual trees as P. coulteri and P. palus-tris exhibited the worst results in terms of cooling effects, with theair temperature reduced by only 0.8–4.0 ◦C over the same period.A cluster of S. siamea, C. pluviosa and T. tipu trees had the best
106 L.V. de Abreu-Harbich et al. / Landscape and Urban Planning 138 (2015) 99–109
Table 2Differences between results in the shade and in the sun.
Trees species Disposition Season Differences of airtemperature (◦C) in thesun and in the shadeduring 10 AM–2 PM
Differences of PET (◦) inthe sun and in theshade during 10 AM–2PM
ooling effects, with their shading reducing the air temperature by.9–11.5 ◦C. These results demonstrate that clusters of trees canitigate temperatures to a greater extent compared with indi-
idual trees. As well, the planting design of clusters trees with 2
ines and 5–10 trees in each line can provide more thermal com-ort than others analyzed. Tree height, canopy size, and shapere features that likely influence the improvement of the thermalnvironment.
Fig. 7. Comparison between plant area index
0.3–1.2 72.30–0.5 89.2 83.4% 0.16
5. Discussion
Thermal bioclimate analysis with respect to air temperature,Tmrt, and PET, for Campinas, Brazil, was able to describe climate
change due to solar radiation attenuated by the shade of trees(Abreu-Harbich et al., 2013a). However, the behavior of arborealspecies is affected by differences in growth conditions and treefeatures (Abreu-Harbich et al., 2012; Bueno-Bartholomei & Labaki,
and solar radiation attenuated by trees.
L.V. de Abreu-Harbich et al. / Landscape and Urban Planning 138 (2015) 99–109 107
ature
22
0P1tm(2iie
aoOfpu
m2(IMttfi(
pausCgf
Fig. 8. Diurnal courses of physiologically equivalent temper
003; Correa et al., 2012; Shahidan et al., 2010; Shashua-Bar et al.,010).
Air temperature reductions are 0–2.8 ◦C for single trees and.3–15.7 ◦C for clusters of trees during the day (10:00 AM to 2:00M) during the study period. The results of the PET are 0.84 to7.5 ◦C for single trees and 0.3 to 15.7 ◦C for clusters of trees forhe same period. Most studies of vegetation influences in urban
icroclimate have been focused in mitigation of air temperaturesAkbari, 2002; Bueno-Bartholomei & Labaki, 2003; Santamouris,001; Scudo, 2002; Shahidan et al., 2010; Shashua-Bar et al., 2010)
nstead of PET and Tmrt. The quantification of tree shading benefits,n terms of PET, provides an accurate measure of the real coolingffects for thermal comfort.
Comparing the results from single trees and clusters of trees,ir temperatures for individual C. pluviosa and T. tipu were aboutne third that of clusters. The PET results we obtained were similar.ur findings suggest that clusters of trees, in different proportions,
unction like a microclimate thermoregulator. The large coveragerovided by clusters of trees is able to mitigate PET through anmbrella effect (Emmanuel, 2005).
Our results suggest that cooling effects are influenced by the per-eability of the crown (Shahidan et al., 2010; Shashua-Bar et al.,
010), and the capacity of shading in attenuating solar radiationAbreu-Harbich et al., 2012; Bueno-Bartholomei & Labaki, 2003).f the maximum mean temperatures of PET during the months of
ay to September are 29 ◦C (Abreu-Harbich et al., 2013a, 2013b),rees that can reduce the PET by greater than 15 ◦C in the win-er, such as M. indica, could provide thermal discomfort. Thesendings confirm the results of Emmanuel (2005) and Lin et al.2010).
Tree features such as tree height, green coverage, shape andermeability of the crown can influence the thermal environment,nd their effects on microclimates could be observed through sim-
lation. The field measurements suggest that trunk and branchingtructure, and size and shape of leaves contribute to cooling effects.. pluviosa is tall, has large coverage, an elliptical crown, a pla-iotropic trunk, and small leaves that are bipinate and linear. Theseeatures cannot be simulated on RayMan Pro.
(PET) (◦C) for different for single trees and clusters of trees.
In outdoor spaces, urban greenery is able to control and improvethermal comfort, and mitigate air temperatures. For indoor areas,tree shading can reduce the incidence of solar radiation on buildingfacades, improve thermal comfort, conserve energy spent on refrig-eration, and maintain a healthy environment (Emmanuel, 2005;Emmanuel et al., 2007; McPherson et al., 1994; Santamouris, 2001).The shape and size of trees can modify the effect in different climateregions (Shashua-Bar et al., 2010; Streiling & Matzarakis, 2003).The evaluation of different commonly found arboreal species andtheir characteristics should be taken into account by profession-als of the urban built environment. This would improve outdoorthermal comfort, reducing the effect of heat islands and ensuring abetter quality of life for people in the urban environment (Abreu-Harbich et al., 2013b; Correa et al., 2012; Shashua-Bar et al., 2010;Streiling & Matzarakis, 2003).
6. Conclusions
From our findings it can be seen that the main influencingparameter in the microclimate and urban environment is mostlydriven and controlled by changes in the Tmrt and wind speed, espe-cially in tropical cities. The size and shape of the tree crown canimprove thermal comfort in a microclimate, as can the size andshape of the leaves, the trunk, and the permeability of the crown.The semi-deciduous C. pluviosa exhibited the best results in termsof PET for both individual and clustered formations. These partic-ular trees have small bipinate linear leaves, plagiotropic trunks,large green coverage, and moderate crown permeability. The crownarchitecture for these trees promotes large green coverage thatfilter solar radiation in accordance with the prevailing season,and allow for the wind to permeate. The phenology of trees alsoneeds to be considered. The shade of native species (Handroanthuschrysotrichus and C. pluviosa) which vary during all the year can be
used for human thermal comfort adaptation.
Clusters of trees can increase the cooling effects of one tree;however, it is important to note how tree formation can promotea large area of shade, especially for aligned clusters. For effectivetree shading along a street, the distance between trees needs to be
1 pe and
rtigttBa
atcostAma
A
tT(fG4
A
i2
R
A
A
A
A
A
A
A
B
B
B
C
C
D
E
08 L.V. de Abreu-Harbich et al. / Landsca
elative to the diameter of the crown. Further studies can quantifyhe thermal comfort provided by different species of trees plantedn streets and open areas and the influence’s distances of thesereen areas in tropical cities. The optimal distribution of singlerees, or clusters, to produce shading during the harshest condi-ions is the main driver for improving human thermal comfort.esides thermal comfort, the ecological factor, economic, cultural,nd aesthetic aspects of urban planning must be considered.
Planning needs to be appropriate for recent climate conditionsnd future climate changes. Planting the appropriate trees aroundhe buildings, in sidewalks, pedestrian ways, squares and parksan be helpful fighting climate change in micro scale. Evaluationf different arboreal species commonly found, and tree-plantingtrategies during the urbanization of cities, is important informa-ion for urban planning and maintaining an urban microclimate.dditionally, tree planting with typical regional trees providingostly shade (C. pluviosa) is a practical and inexpensive solution,
nd is considered as an energy efficient alternative.
cknowledgements
This research was supported by São Paulo Research Founda-ion (FAPESP) research grant (08/05870-5), National Counsel ofechnological and Scientific Development (CNPq) research grant311641/2013-0), and research cooperation between Coordinationor the Improvement of Higher Education Personnel (CAPES) anderman Academic Exchange Service (DAAD) research grant (BEX234/10-3).
ppendix A. Supplementary data
Supplementary data associated with this article can be found,n the online version, at http://dx.doi.org/10.1016/j.landurbplan.015.02.008.
eferences
breu-Harbich, L. V., Labaki, L. C., & Matzarakis, A. (2012). Different trees and con-figuration as microclimate control strategy in Tropics. In Proceedings of theinternational conference on passive and low energy architecture, 2012 Lima, PE,.Lima: PLEA.
breu-Harbich, L. V., Labaki, L. C., & Matzarakis, A. (2013a). Thermal bioclimate as fac-tor in urban and architectural planning in tropical climates – The case of Camp-inas, Brazil. Urban Ecosystems, http://dx.doi.org/10.1007/s11252-013-0339-7
breu-Harbich, L. V., Labaki, L. C., & Matzarakis, A. (2013b). Thermal bioclimatein idealized urban street canyons in Campinas, Brazil. Theoretical and AppliedClimatology, 115, 333–340. http://dx.doi.org/10.1007/s00704-013-0886
kbari, H. (2002). Shade trees reduce building energy use and CO2 emissions frompower plants. Environmental Pollution, 116, 119–126.
kbari, H., & Rose, L. (2008). Urban surfaces and heat island mitigation potentials?Human–Environment System, 11(2), 85–101.
kbari, H., Rosenfeld, A., Taha, H., & Gartland, L. (1996). Mitigation of summer urbanheat islands to save electricity and smog. Atlanta, GA: Paper presented at the76th American Meteorological Society Annual Meeting, Report no. LBL-37787.American Meteorological Society.
kbari, H., & Taha, H. (1992). The impact of trees and white surfaces on residentialheating and cooling energy use in four Canadian cities? Energy, 17(2), 141–149.
ernatzky, A. (1979). Grünflächen und Klima [Green spaces and climate]. DBZ –Forschung und Praxis, 080 DBZ 8/79, 1205–1209.
rown, R., & Gillespie, T. (1995). Microclimate landscape design: Creating thermalcomfort and energy efficiency. New York: John Wiley & Sons.
ueno-Bartholomei, C. L., & Labaki, L. C. (2003). How much does the change of speciesof trees affect their solar radiation attenuation? Paper presented at the fifth inter-national conference on Urban Climate, Lodz, Poland.
ardelino, C. A., & Chameides, W. L. (1990). Natural hydrocarbons, urbanization andurban ozone. Journal of Geophysical Research, 95, 13971–13979.
orrea, E., Ruiz, M. A., Canton, A., & Lesino, G. (2012). Thermal comfort in forestedurban canyons of low building density. An assessment for the city of Mendoza,
Argentina. Building and Environment, 58, 219–230. http://dx.doi.org/10.1016/j.buildenv.2012.06.007
imoudi, A., & Nikolopoulou, M. (2003). Vegetation in the urban environment:Microclimatic analysis and benefits. Energy and Buildings, 35, 69–76.
mmanuel, M. R. (2005). An urban approach to climate-sensitive design: Strategies forTropics. London: E & FN Spoon Press., 172 pp.
Urban Planning 138 (2015) 99–109
Emmanuel, R., Rosenlund, H., & Johansson, E. (2007). Urban shading – A designoption for the tropics? A study in Colombo, Sri Lanka. International Journal ofClimatology, 27(14), 1995–2004.
Grimmond, C. S. B. (2007). Urbanization and global environmental change: Localeffects of urban warming. Geographical Journal, 173, 83–88.
Guderian, R. (2000). Arten und Ursachen von Umweltbelastungen. In R. Guderian(Ed.), Handbuch der Umweltveränderungen und Ökotoxikologie, Band 1A: Atmo-sphäre (pp. 1–60). Heidelberg: Springer-Verlag.
Gulyás, A., Unger, J., & Matzarakis, A. (2006). Assessment of the microclimatic andthermal comfort conditions in a complex urban environment: Modeling andmeasurements. Building and Environment, 41, 1713–1722.
Heisler, G. M. (1977). Trees modify metropolitan climate and noise. Journal of Arbori-culture, 3, 201–207.
Herrington, L. P. (1977). The role of the urban forests in reducing urban energyconsumption. Proceedings of the Society of American Foresters, 20–66.
Holst, T., Hauser, S., Kirchgässner, A., Matzarakis, A., Mayer, H., & Schindler, D. (2004).Measuring and modelling plant area index in beech stands. International Journalof Biometeorology, 48, 192–201.
Höppe, P. (1993). Heat balance modelling. Experientia, 49, 741–746.Höppe, P. (1999). The physiological equivalent temperature – A universal index
for the biometeorological assessment of the thermal environment. InternationalJournal of Biometeorology, 43, 71–75.
Kottek, M., Grieser, J., Beck, C., Rudolf, B., & Rubel, F. (2006). World Map of theKöppen-Geiger climate classification updated. Meteorologische Zeitschrift, 15(3),259–263.
Lin, T. P., & Matzarakis, A. (2008). Tourism climate and thermal comfort in Sun MoonLake, Taiwan. International Journal of Biometeorology, 52, 281–290.
Lin, T. P., Matzarakis, A., & Hwang, R. L. (2010). Shading effect on long-term outdoorthermal comfort. Building and Environment, 45, 213–221.
Matzarakis, A. (2013). Stadtklima vor dem Hintergrund des Klimawandels [Urbanclimate in the context of climate change]. Gefahrstoffe – Reinhaltung der Luft, 73,115–118.
Matzarakis, A., & Endler, C. (2010). Adaptation of thermal bioclimate under climatechange conditions – The example of physiologically equivalent temperature inFreiburg, Germany. International Journal of Biometeorology, 54, 479–483.
Matzarakis, A., & Mayer, H. (1996). Another kind of environmental stress: Thermalstress. WHO Collaborating Centre for Air Quality Management and Air PollutionControl. Newsletters, 18, 7–10.
Matzarakis, A., Rutz, F., & Mayer, H. (2007). Modelling radiation fluxes in simple andcomplex environments – Application of the RayMan model. International Journalof Biometeorology, 51(4), 323–334.
Matzarakis, A., Rutz, F., & Mayer, H. (2010). Modelling radiation fluxes in simpleand complex environments: Basics of the RayMan model. International Journalof Biometeorolology, 54(2), 131–139.
Mayer, H. (1993). Urban bioclimatology. Experientia, 49, 957–963.Mayer, H., & Höppe, P. (1987). Thermal comfort of man in different urban envi-
ronments. Theoretical and Applied Climatology, 38, 43–49. http://dx.doi.org/10.1007/BF00866252
Mayer, J. D., Salovey, P., & Caruso, D. R. (2008). Emotional intelligence: New abilityor eclectic mix of traits? American Psychologist, 63, 503–517.
McPherson, E. G., Nowak, D. J., & Rowantree, R. A. (1994). Chicago’s urban forestecosystem: Results of the Chicago Urban Forest Climate Project. Department of Agri-culture, Forest Service, Northeastern Forest Experiment Station, NortheasternFlorest Experimental Station.
Meyer, F. H., & Bauermel, G. (1982). (Trees in the city) Bäume in der Stadt. Stuttgart,Germany: Eugen Ulmer Verlag., 380 pp.
Montague, T., & Kjelgren, R. (1998). Urban tree transpiration over turf and asphaltsurfaces. Atmospheric Environment, 32(1), 35–41.
Monteiro, L. M., & Alucci, M. P. (2010). Proposal of an outdoor thermal com-fort index for subtropical urban areas. Paper presented at the 3rd Passive &Low Energy Cooling for the Built Environment conference, Rhodes Island,Greece.
Nackaerts, K., Coppin, P., Muys, B., & Hermy, M. (2000). Sampling methodology forLAI measurements with LAI-2000 in small forest stands. Agricultural and ForestMeteorology, 101, 247–250.
Neumann, H. H., Hartog, G., & Shaw, R. H. (1989). Leaf area measurements based onhemispheric photographs and leaf-litter collection in a deciduous forest duringautumn leaf-fall. Agricultural and Forest Meteorology, 45, 325–345.
Nunes, L. H. (1997). (Spatial and temporal distribution of rainfall in the São Paulo state:Variability, trends, processes involved) Distribuic ão espac o-temporal da pluviosi-dade no Estado de São Paulo: Variabilidade, tendências, processos intervenientes(Thesis). University of São Paulo, Geography Institute., 192 pp.
Oke, T. R. (1989). The micrometeorology of the urban forest. Philosophical Transac-tions of the Royal Society of London, B324, 335–349.
Santamouris, M. (2001). Energy and climate in the urban built. London: James & James.Scudo, G. (2002). Thermal comfort in green spaces. In Green structures and
Shahidan, M. F., Shariff, M. K. M., Jones, P., Salleh, E., & Abdullah, A. M. (2010). Acomparison of Mesua ferrea L. and Hura crepitans L. for shade creation and radia-
tion modification in improving thermal comfort. Landscape and Urban Planning,97(3), 168–181.
Shashua-Bar, L., & Hoffman, M. E. (2000). Vegetation as a climatic component inthe design of an urban street. An empirical model for predicting the coolingeffect of urban green areas with trees. Energy and Buildings, 31(3), 221–235.http://dx.doi.org/10.1016/S0378-7788(99)00018-3
pe and
S
S
S
S
L.V. de Abreu-Harbich et al. / Landsca
hashua-Bar, L., Pearlmutter, D., & Erell, E. (2009). The cooling efficiency of urbanlandscape strategies in a hot dry climate. Landscape and Urban Planning, 92(3–4),179–186. http://dx.doi.org/10.1016/j.landurbplan.2009.04.005
hashua-Bar, L., Potchter, O., Bitan, A., Boltansky, D., & Yaakov, Y. (2010). Microcli-mate modelling of street tree species effects within the varied urban morphologyin the Mediterranean city of Tel Aviv, Israel. International Journal of Climatology,
57, 44–57.
pangenberg, J., Shinzato, P., Johansson, E., & Duarte, D. (2008). Simulation of theinfluence of vegetation on microclimate and thermal comfort in the city of SaoPaulo. Revista SBAU, 3(2), 1–19.
teven, M., Biscoe, P., Jaggard, K., & Paruntu, J. (1986). Foliage cover and radiationinterception. Field Crops Research, 13, 75–87.
Urban Planning 138 (2015) 99–109 109
Streiling, S., & Matzarakis, A. (2003). Influence of single and small clusters of treeson the bioclimate of a city: A case study. Journal of Arboriculture, 29, 309–316.
Tsutsumi, J. G., Ishii, A., & Katayama, T. (2003). Quantity of plants and its effect onlocal air temperature in an urban area. Paper presented at the fifth internationalconference on urban climate, Lodz, Poland.
VDI. (1998). VDI 3787, Part I: Environmental meteorology, methods for the human
biometeorological evaluation of climate and air quality for the urban and regionalplanning at regional level. Part I: Climate. Berlin: Beuth., 29 pp.
Yilmaz, S., Toy, S., Irmaka, M. A., & Yilmaz, H. (2007). Determination of climaticdifferences in three different land uses in the city of Erzurum, Turkey. Build-ing and Environment, 42(4), 1604–1612. http://dx.doi.org/10.1016/j.buildenv.2006.01.017
![UNESCO Constitution, 1945 - Aventri · UNESCO-Recommendations. single monument urban landscape ensemble urban landscape. landscape approach to „[…] maintain urban identity“](https://static.documents.pub/doc/80x56/5fa596629897da76da21984b/unesco-constitution-1945-aventri-unesco-recommendations-single-monument-urban.jpg)
