Stretch: a spatially Stretch: a spatially explicit individual explicit individual based forest based forest simulator simulator Montpellier, France L.Soler, D. Harja Asmara, M. Laurans, C.Madeleine, J.Dauzat, G. Vincent, F. de Coligny
Jan 19, 2016
Stretch: a spatially Stretch: a spatially explicit individual based explicit individual based
forest simulatorforest simulator
Montpellier, France
L.Soler, D. Harja Asmara,M. Laurans, C.Madeleine, J.Dauzat,G. Vincent, F. de Coligny
Model portingModel porting From Sexi-FS (Degi Harja Asmara, From Sexi-FS (Degi Harja Asmara,
Grégoire Vincent)Grégoire Vincent) Increase the versatility/genericity of the Increase the versatility/genericity of the
modelmodel Modifications of processesModifications of processes Use functionalities of CapsisUse functionalities of Capsis TransferTransfer
Plasticity is one of the major axis of the Plasticity is one of the major axis of the laboratory AMAPlaboratory AMAP
Two Phd student work on this subjectTwo Phd student work on this subject
StretchStretch
Spatially explicitSpatially explicit Individual basedIndividual based Multi speciesMulti species 3D3D
Crown shape plasticityCrown shape plasticity LightLight Space limitationSpace limitation
The yearly simulation loopThe yearly simulation loop
mechanical constraints (BIOMECHANICS)
light availability (MMR,SLIM,Liebermann)
mortality
Regeneration
Tree overall dimension change, Crown deformation, phototropism, collision
Process Growth
Initialisation stepEnvironnement settingsScene initialisation (trees, terrain)Species initialisation (reference tree growth)
Legend:Red : additional options to the model with crownBlack : model without considering the crown
Current volume
Growth Reducer
New VolumePotential volume Increment
New dbh
Stem Growth algorithmStem Growth algorithm dbh function : Chapman Richards functiondbh function : Chapman Richards function Growth of stem volume :Growth of stem volume : Ln(vol(t)) = u + v*ln(dbh(t))+w*ln(h(t))Ln(vol(t)) = u + v*ln(dbh(t))+w*ln(h(t))
New height
Light
Crown growthCrown growth Depends on the stem growthDepends on the stem growth Virtual vectors of branchesVirtual vectors of branches PolygonesPolygones
LiebermanLieberman Calcul of the index of closure of the canopy : GCalcul of the index of closure of the canopy : G G caracterises the light environmentG caracterises the light environment
Δhi = hi - hhpi = √(d²i+Δh²i)sinΘi = Δhi /hpi
G = Σi sinΘ
M. Lieberman, D. Lieberman, R. Peralta, G.S. Hartshorn, 1995, « Canopy closure and the distribution of tropical forest tree species at La Selva, Costa rica »,Journal of Tropical Ecology, 11:161-178
Calcul of Light Growth Calcul of Light Growth ReducerReducer
The index G by interpolation will The index G by interpolation will determine the Light Growth Reducer (LGR)determine the Light Growth Reducer (LGR)
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
-0.5 0 0.5 1 1.5
shade tolerant
light demanding
shade specialist
G
1-LGR
Mortality algorithmMortality algorithm
Primary mortalityPrimary mortality
- vigour (survival - vigour (survival probability, growth reducer, mortality probability, growth reducer, mortality function)function)
- senescence (dbhMax, - senescence (dbhMax, volumeMax, heightMax…)volumeMax, heightMax…)
Graphic interfaceGraphic interface
To doTo do
Alternative algorithm for dbh growthAlternative algorithm for dbh growth Alternative algorithm for height/dbh allometryAlternative algorithm for height/dbh allometry
Primary mortality (add biomecanics Primary mortality (add biomecanics constraints)constraints)
Secondary mortality Secondary mortality
RegenerationRegeneration 3D viewer3D viewer
To doTo do
Crown deformation moduleCrown deformation module- assymetric crown shape deformation- assymetric crown shape deformation- crown grow to reach the light- crown grow to reach the light
• Deformation can be local (radial anisotropy of light and available space)
• Local deformation is modeled via a set of independent vectors stemming from crown base subtending the crown envelope
SLIM and MMR
SExI-FS Scene
Simple Light Interception Model (SLIM)
A computed canopy openness compared to the real location in the forest.
This method is similar to hemispherical photographs, which are normally taken at ground level.
Shape transformation response of trees in
crowded habitats (STReTCH)
MMR
Ws, Wr Ts, Tr soil
W soil
measurementsmeasurementssimulatorsimulator
Micrometeo.Data Set
Light partitioning
PAR NIR TIR
Incident radiation
BRDFLIDAR
TIR Emittance
Cartography of soil irradiance, temperature and humidity
wind RHair Tair
E
H
Turbulent transfers
Air profiles
E H
RemoteSensing
RHair
Tair
irradiation
temperature
transpiration
photosynthesis leaf
sap
flow
MMR: one module in Archimed
MIRIncident radiation
MUSCMultiple scattering
RADBALRadiation balance
Meteo.
data
lightonsoil
plantIrradia-
tion
scenerad.
balance
Meteo.
details
Basic principle of MIR
All objects you can see when back to the sun are sunlit
Basic principle of MIR
Splitting skyhemisphere
with the"TURTLE"
model
Discretisation of incident radiation
The total leaf irradiation is
obtained by weighting
its partial irradiation
from each source
Mapping leaf irradiation
Échelles de modélisationmodèles numériques multi-échelles
SExI-FS Scene
Mir images
MMR
22
11
33
3322
11
The projections
of plants
are moved
modulo the
dimensions
of the scene
Virtual plot duplicationVirtual plot duplication
Altitude first hitAltitude first hit
Nb hits in layer 1Nb hits in layer 1
LAYERSLAYERS
00
11
22
33
Nb hitsNb hits in layer 2in layer 2
Nb hitsNb hits in layer 3in layer 3
Information for each pixelInformation for each pixel
The MUSCmodel isbased on
lightinterceptionprobabilities
output bythe MIRmodel
MuSc : calcul des "MUltiple SCattering
Daily irradiation