7. Taking into account climate effects on forest dynamics

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7. Taking into account climate effects on forest dynamics
Modelling climate effects on forest dynamics: Dynaclim project
Hendrik Davi
Plan
3. Introduction
5. Modelling forest carbon and water cycles: Average tree approach
7. Taking into account climate effects on forest dynamics: coupling
functional and dynamics models
9. Dynaclim schem
Introduction
Variations depuis 1000
(GIEC, 2007)
Introduction
CO2 increase
Climatic changes
Forest dynamics
Management
N,P deposition
Land use changes Vegetation functionning
Forest carbon sink
Modelling climate effects on forest dynamics: Dynaclim project
Hendrik Davi
Plan
3. Introduction
5. Modelling forest carbon and water cycles: Average tree
approach
7. Taking into account climate effects on forest dynamics: coupling
functional and dynamics models
9. Dynaclim schema
Estimating carbon fluxes Leaves respiration
Canopy photosynthesis
Wood respiration
Roots respiration
Heterotrophic respiration
Estimating water fluxes
rain
Water interception by leaves
Transpiration
Drainage
Soil evaporation
CASTANEA (Dufrêne et al., 2005)
Average tree model
Canopy= n layers
Reserve compartment unlocated
Soil= 2 layers
Trunc and branches
Fine and coarses roots
CASTANEA (Dufrêne et al., 2005)
Leaf carbon budget
H20 budget
Canopy
Na=f(Nm)*LMA
Ryan
Rf= f(Na,T)
Farquhar A=f(Na,T,PAR)
PAR (Verhoef)
LAI
ETR
Penman
Monteith
LMA
EPsol (Penman)
SOC (Parton)
NPP
Ball & al
Gs= f(A,HR)
Gc
C­H2O­Ε
ecosystem
Soil Water Model
Sala & al
Multi­layer model
Key ecosystem parameters
Leaves traits • Leaf Area Index (LAI)
• Leaf nitrogen content (N)
• Leaf Mass per Area (LMA)
Aboveground biomass
(Bwood)
Roots biomass
(Broots)
Soil Water Reserve
(SWR)
Soil Organic Carbon
(SOC)
Branch bag
Dendrometer
Gas exchange
sapflow
Biochemical
photosynthesis
photos
LAI2000
Hesse: beech
Le Bray: maritime pine
Puéchabon: Holm oak
Loobos: Scots pine
NEE gC m d
­2 ­1
6
Hesse 2001
4
2
0
­2
­4
­6
­8
beech
­10
­12
1­janv 11­mar 20­may 29­juil 7­oct
measurements
simulations
NEE g C m­2d ­1
Model evaluation on Net Ecosystem Exchange (Davi et al. 2006a) 3
3
Puéchabon 2001
7­oct
16­déc
Loobos 1997
2
1
0
­1
­2
­3
16­déc
measurements
1
­4
7­oct
simulations
NEE g C m­2 d­1
C m d
NEEC g
­2 ­1
2
16­dec
3
le Bray 2001
2
1
0
­1
­2
­3
­4
­5
Maritime pine
­6
1­janv 11­mars 20­mai 29­juil
0
­1
­2
­3
­4
Holm oak
­5
1­janv 11­mars 20­mai
simulations
measurements)
­5
29­juil
7­oct
16­déc
Scots pine
­6
1­janv
11­mars 20­mai
measurments
simulations
29­juil
5
­1
Branch bag
4
3
2
1
0
9­avr
29­mai
Asssimilation mesurée
18­juil
6­sept
REW
4
3
2
y = 1,03x + 0,01
2
R = 0,95
1
26­oct
0
0
Assimilation simulée azote foliaire diminuant au cours de
la saison
Transpiration du couvert
5
6
simulée mm jour
Photosynthèse journalière µmol CO2 m ­2
Model evaluation on several processes (Davi et al. 2005) 1
2
3
4
­1
mesurée par flux sève mm jour
Eau du sol à Hesse 1997­2001
1,4
1,2
1
0,8
0,6
0,4
0,2
0
0
150
300
450
600
750
simulé
5
900
1050
mesuré
1200
1350
1500
1650
1800
Effect of global change (Davi et al., 2006a)
Contribution to trend
gC m ­2 y­1
6
3
0
­3
­6
Bray SO Pinus p.
Puéchabon Hesse Fontainebleau Fontainebleau Fontainebleau
SE Quercus i. NE Fagus s. N Quercus p. N Fagus s.
N Pinus s.
CO2 effect
Water stress effect
Other climatic effects
Interaction effects
Phenology effect
Summary of the role played by each factor of global changes in simulated trends on NEE between 1960 and 2100.
Modelling climate effects on forest dynamics: Dynaclim project
Hendrik Davi
Plan
3. Introduction
5. Modelling forest carbon and water cycles: Average tree approach
7. Taking into account climate effects on forest dynamics:
coupling functional and dynamics models
9. Dynaclim schema
The forest dynamics: one example
Montage photo : ONF
The forest dynamics: one example Ventoug model
Beech regeneration under pine canopy
1 dynamique, 2 (ou 3) variantes :
Pin + Hêtre
1
versant sud
Hêtre pur
1 bis
versant sud
Pin
P. nigra
P. sylvestris
P. uncinata
2
Sapin
+ Hêtre
+ Pin
versant Nord
P. Dreyfus
South of Mont­Ventoux : Example of simulated dynamics
Pine
1
P. nigra, P. sylvestris
P. uncinata
Pine + beech
P. Dreyfus
The processes: How integrate climate?
Growth : dH, dD = POT
x RED1
x RED2
(species, age, fertility)
(density, canopy structure, species)
(competition, species )
Mortality : ­ Probability = f (species, RED1, RED2 )
Regenération : ­f (age of sources and distance sink­source) Integrate climate effect and explicit fertility effect
• which structure ?
• how much ecophysiology ?
Dynamics
Functioning
Models type
tree
Cohorts
tree
Spatially explicit
­
Cohorts
Average tree
Spatially explicit
­
+
+
Description of processes
Reproduction
Dispersion
Vertical fluxes
Efficient dispersion
Energy budget Cycle C
Germination
Growth
Growth of saplings
Mortality
Mortality due
to perturbations
leaves
Trunk
Cycle H2O
Roots
Lateral fluxes
Soil
Modelling climate effects on forest dynamics: Dynaclim project
Hendrik Davi
Plan
3. Introduction
5. Modelling forest carbon and water cycles: Average tree approach
7. Taking into account climate effects on forest dynamics: coupling
functional and dynamics models
9. Dynaclim schema
One example :Hybrid approach Dyanclim model
Structure integration
Climate and fertility
Resolution of functional models (ex 1 ha)
Model « Average Tree »
Available carbon for growth
Fine resolution of dynamics models (ex 100 m²)
Model tree semi­spatially explicit
Equations of
Growth
Survival
Regeneration
The spatial levels
T
Tree Interaction between trees
cells de 10 x 10 m²
TLC
Interaction between cells
Group of cells
Forest Functionning
FLC
expansion :
Sample of group
«Analyse unit »: management : UA
interactions Seeds fluxes
Forest
H. Davi
CASTANEA Lib
F
region
Dynaclim
P. Dreyfus
VentouxG
Dynaclim in CAPSIS
scenario
Gidcard
Methodprovider
step
Gsettings
Gmodel
GStand
Gtree
FmSpecies
*
FmSettings
Dcsettings
GTCStand
GMaddtree
DcModel
DcMethodprovider
Gplot
Polygonalplot
DcStand
DcInventory
DcSpecies
*
FmClimate
FmClimateReader
FmClimateDay
FmSpeciesReader
DcAU
DcFLCell
DcTree
FmSoilLayer *
FmCanopy
FmWood
FmSoilLayer *
Polygonalcell
DcPlot
FmSoil
DcTLCell
Squarecell
Some conclusions
Four challenges:
3. Effect of climate on unknown processes: Ventoux as “site atelier”
• Allocation
• Reproduction
• Growth of saplings
• Mortality=> existing of drought threshold and link with other biological effects (insects)
4. How link dynamics and functioning: what accuracy for what aim?
5. Management effect and interaction with climate
6. How infer some generalization to improve ecological theories?
Use process base model to test theory of community ecology and evolution
=> Couple genetics model and dynamics models (fitness, plasticity) and use as theoretical tools

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