From wildfires to prescribed fires: resilience of heathlands under different fire regime parameters
https://fireseves.blogspot.com/ SEFIRECYL (LE001P17)
Leonor Calvo*, Reyes Tárrega, Susana Suárez-Seoane, Luz Valbuena, Angela Taboada, Elena Marcos
Area of Ecology. Faculty of Biological and Environmental Sciences.University of Leon, Spain. E-mail:[email protected]
MINECO AGL2017-86075-C2-1-R https://sefirecyl.unileon.es/
“Applied Ecology and Remote Sensing group”
http://ecologiaaplicadayteledeteccion.blogspot.com/
Fire ecology
Wildfires Prescribed fires
Resilience
From wildfires to prescribed fires
The main objective: to compare the resilience of the same type of ecosystems (heathlands) under two scenarios-wildfire vs prescribed fires.
Propose management tools to reduce the damage caused by wildfires
1. Why are wildfires a problem?
2. Which are the environmental drivers of burn severity?
3.- How resilient are the fire-prone ecosystems after wildfire vs prescribed fires?
4.- Are prescribed fires a possible solution to reduce the burn severity of wildfires?
From wildfires to prescribed fires
Dimensions of forest fire impacts
Serious economic damage Loss of human lives
3. Ecological impacts
2. Economic impacts1. Social impacts
1. Why are wildfires a problem?
California= 81 Portugal= 62 Galicia= 4
GIF (2007-2017)
Doerr SH, Santın C. 2016. Global trends in wildfire and its impacts: perceptions versus realities in a changing world. Phil. Trans. R. Soc. B 371: 20150345.
Human relationship with wildfires
Bowman et al., 2011. The human dimension of fire regimen on earth. J. Bigeogr. 38: 223-2236
Arson fires
Dimensions of forest fire impacts1. Why are wildfires a problem?
1.-Rural abandonment results in the expansion of forest
2.- Lack of forest management results in an increase in fuel loads and continuity
Fire regime: severity
3.- Climate change: increase of temperature and decrease of precipitation
+
The resilience of ecosystems after fire depends on:
1.- Fire regime attributes: BURN SEVERITY2.- Vegetation traits: Regeneration ability3.- Post-fire conditions: abiotic factors
1. Why are wildfires a problem?
Ryan (2002)
1. Why are wildfires a problem?
2. Which are the environmental drivers of burn severity?
3. How resilient are the fire-prone ecosystems after wildfire vs prescribed fires?
4. Are prescribed fires a possible solution to reduce the burn severity of wildfires?
From wildfires to prescribed fires
La Cabrera= 9,960 ha burned in August 2017
Heathland 65%Pastureland
GrasslandForest
2. Which are the environmental drivers of burn severity?
Keeley, 2009
Heathlands with large shrub skeletons retaining small twigsindicative of fire severity.
BURN SEVERITY
2) Field burn severity: Minimum Twig Diameter of Erica australis1) Spectral burn severity: dNBR
2. Which are the environmental drivers of burn severity?
Pre-fire vegetationstructure
Physical properties
Weather conditions
Fire history
Severity
Severity: conditions---- Pre-fire management
Topography-Slope-Aspect
Garcia Llamas et al., 2019. Forest Ecology and ManagementGarcía Llamas et al., 2019. International Journal of Wildland Fire
Random Forests
-Composition: SIOSE-Heterogenity: LIDAR
-Recurrence- Time since last fire
-Spring rainfall-Summer rainfall
Severity: conditions---- Pre-fire management
0
0.2
0.4
0.6
0.8
1Pr
e-fir
e ve
geta
tion
stru
ctur
e
Wea
ther
Fire
hist
ory
Phys
ical p
rope
rties
Pars
imon
ious
Full
mod
el
Varia
nce
expl
aine
d
0.33
2
0.19
2
0.06
0
0.18
0
0.48
7
0.49
5
Fire severity variance explained by Random Forest models using different categories of predictors: pre-fire vegetation structure, weather conditions, fire history and physical properties. The figure alsoshows the results of both the most parsimonious model and the full model.
Pre-fire vegetation structure is the main factor driving burn severity in fires occurred in heathlands
Partial dependence plots showing the relationship between fire severity (dNBR) and the most significant explanatory variables included in the mostparsimonious model. Numbers within each plot show the normalized importance of each variable in the model measured as % IncMSE (imp =).
Severity: conditions---- Pre-fire management
1) High shrub (fuel) accumulation= high severity2) High spatial heterogeneity= low severity
Prescribed fires could be an appropriated management tool to increase heterogeneity
Heterogeneity
Among Pre-fire vegetation structure we identified:Shrub cover area
1. Why are wildfires a problem?- Dimensions of wildfires
2. Which are the determining factors of burn severity?
3.- How resilient are the fire-prone ecosystems after wildfire vs prescribed fires?
4.- Are prescribed fires a possible solution to reduce the burn severity of wildfires?
From wildfires to prescribed fires
Zone B
020406080
100120140160180
2 3 4 5 6 7 8 9 10 11 12 13 14 15
Years after burning
Mea
n co
ver %
Annual HerbsPerennial herbsWoody species
3.- How resilient are our fire prone ecosystems after wildfire vs prescribed fires?
Prescribed fires
0102030405060708090
100
Original 1 year 3 years 4 years 5 years 9 years 12 years 15 years
Mea
n co
ver %
Erica australis
31%
Erica australis heathlands
Total cover
Wildfires
29%
45%
15%
0
20
40
60
80
100
120
Control Low severity Moderate severity High severity
Tota
l co
ver %
5%15%
3%0
10
20
30
40
50
60
70
Control Low severity Moderate severity High severity
Mea
n co
ver %
Erica australis
1 year after fire
1 year after fire
Erica australis heathlands
3.- How resilient are our fire prone ecosystems after wildfire vs prescribed fires?
1. Why are wildfires a problem?
2. Which are the determining factors of burn severityosystems?
3.- How resilient are the fire-prone ecosystems after wildfire vs prescribed fires?
4.- Are prescribed fires a possible solution to reduce the burn severity of wildfires?
From wildfires to prescribed fires
4.- Are prescribed fires a possible solution to reduce the burn severity of wildfires?
- We need a new vision about wildfires, where the focus is shifted from fire suppression tofire prevention: managing our forestry systems to be more resilient.
Proposal: prescribed fires to create a more heterogeneous landscape and enhance theresilience of ecosystems
- New challenges associated with the problematic of wildland-urban-interfaces (WUI)
Proposal: in areas with low population density plus abandonment of traditional land use, weshould consider the application of prescribed fires to reduce the fuel loads around thevillages to prevent the negative social, economic and ecological impacts of larges wildfires
4.- Are prescribed fires a possible solution to reduce the burn severity of wildfires?
Thank you for your attention
L. CalvoS. Suárez R. Tárrega L. Valbuena E. MarcosA. Taboada
“Applied Ecology and Remote Sensing group”
http://ecologiaaplicadayteledeteccion.blogspot.com/
Número de diapositiva 1Número de diapositiva 2Número de diapositiva 3Número de diapositiva 4Número de diapositiva 5Número de diapositiva 6Número de diapositiva 7Número de diapositiva 8Número de diapositiva 9Número de diapositiva 10Número de diapositiva 11Número de diapositiva 12Número de diapositiva 13Número de diapositiva 14Número de diapositiva 15Número de diapositiva 16Número de diapositiva 17Número de diapositiva 18Número de diapositiva 19