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Réduction de la biomasse en forêt boréale de l’Est du Canada sous l’effet
des changements climatiques
Emeline ChastePhD in Environmental ScienceUniversity of Quebec in Montreal (Canada)École Pratique des Hautes Études(France)
Supervision :Martin Girardin, Christelle Hély, Yves Bergeron
Collaboration: Jed Kaplan
Jour
née
Mod
èle
Qué
bec
Jeud
1 1e
r no
vem
bre
2018
11
Intr
oduc
tion
5
Objectives
3
The tool used:
� Evaluate how climate, atmospheric [CO2] and wildfires mayaffect the biomass of dominant tree species in Canada’s managedboreal forest in the coming decades;
� Assess the spatial heterogeneity in climate change impacts, notablyalong temperature (e.g. north to south) and precipitation (e.g. west toeast) gradients.
Picea Abies Pinus Populus
Reparameterized for 4 PFTs:
CLIMATE
VEGETATION FIRE
(Chaste et al. 2018)
Mét
hodo
logi
e
6
LPJ-LMfire model
4
WeathergeneratorIn
puts
Out
puts
Environmental
constraints
Climate
Fire % cover
Biomass NPP
ECOSYSTEM
Daily processes
Annual processes
Reproduction
Establishment
Mortality
Fire
Leafs-roots-wood
turnover
Biomassallocation &
growthStomatalregulation
Photosynthesis
Plant respiration
Leafs-rootsphenology
Decomposition
Soilhydrology
Mét
hodo
logi
e
8
Input datasets(1950 - 2099)
5
1 2
3 4
5
6
7
Climate : Maps of monthly mean for 7 variables
Environmental constraints: Maps of…
4 variables 3D
1
2
3
4
10 km x 10 km
Mét
hodo
logi
e
8
Input datasets(1950 - 2099)
5
1 2
3 4
5
6
7
Climate : Maps of monthly mean for 7 variables A multi-model ensemble of 6 climate scenarios
(6CS) that combines:
RCP: 4.5 8.5
GCM:
EARTH
GCM:CanESM2
EC-EARTH
RCM: RCA4
CanRCM4+ +
10 km x 10 km
H0
1
LPJ-LMfire: Annual burn rates (%)R
ésul
tats
6-60% -
75%
-33%
-24% -
35%
+2% (-8;+12)
Changes in the 2071-2099 period relative to 1951-1980
+
-
Reduction of fire activity
In summary:
1
LPJ-LMfire: Biomass (T.ha-1)
7-33%
-55%
+7%
-7% -13%
+7%
+
-
Decrease in biomass
In summary:
Changes in the 2071-2099 period relative to 1951-1980
Rés
ulta
ts
(1) forest cover loss(2)(3)
1
LPJ-LMfire: Tree cover (%)
8
-33%
-55%
-7%-
13%
Decrease inbiomass
associated with…
coniferous speciesPopulus (1) forest cover gain
(2)(3)
Increase inbiomass
associated with…
coniferous speciesPopulus
+7%+7%
Cumulative tree cover (%) are not correct (see Chaste et al. 2018), but:
Rés
ulta
ts
1
LPJ-LMfire: Growth (NPP; T.ha
9+11%
-27%
+86%
+25%+19%
+44%
In summary:
-
+
Increase in NPP
Changes in the 2071-2099 period relative to 1951-1980
Rés
ulta
ts
1
LPJ-LMfire: results coherence?Decrease in firesDecrease in fires Increase in NPPIncrease in NPP
Decrease in biomassDecrease in biomass
Detailed analyses
10
Rés
ulta
ts
1
LPJ-LMfire: Detailed analyses
Second half of the 21st century:establishment rates
that do not compensate forheat-induced mortality rates
+ -
West East
11
Rés
ulta
ts
1
LPJ-LMfire: Detailed analyses Who's acting on the forest cover loss?
12
Rés
ulta
ts
Con
clus
ion
1
To keep in mind : Impacts of climate change will be very significant throughout Canada’smanaged boreal forest by the end of the 21st century, but they will be subjectto major differences across the region:
13
Climate changeClimate change
FireFire
Forest
Tree cover(%)
Biomass(T.ha-1)
Composition
NPPNPP
+
-
+
+
Heat-inducedtree mortality
rates
Heat-inducedtree mortality
rates
-
-
+
SouthNorth and South /
(1) Vegetation "bottom-up" control;
(2) Stimulating effects of increasingtemperatures and atmospheric[CO2] on boreal forest productivity;
(3) heat-induced mortalityevents
forest cover loss
negative feedback on fires
The enhancement ofvegetation growth by climatechange would not beunlimited and may becounteracted by the negativeeffects of climate change onfires and other plantprocesses, such as tree
1
Many thanks to:� Martin Girardin, Christelle Hély and Yves Bergeron
� Professor Jed Kaplan from the University of Lausanne
� Xiao Jing Guo , biostatistician at the Laurentianforestry center
� Daniel Stubbs, scientific analyst at Calcul Quebec
� Travis Logan, specialist at Ouranos Consortium
� Our partners:
14
1
Questions?
15