Option 2:simulating with several parameter sets

Forest simulation model
造林学
小林壱德久
木一代，人三代
All of a sudden…
• 気候変動化における森林の長期的な変化を
研究したい
Someone wants to research long-term
changes in forest under climate change
→長らく調査されてきた
研究地でないと難しい
But it’s difficult to start it unless the plot was
already researched for a long time
シミュレーション
• 従来の予測といえば森林の”平均的”成長量
We have used simulation showing forest’s average state
林分密度管理図
• コンピュータの発達により，樹木一本々を
シミュレーションすることが可能になった
Now forest can be simulated tree by tree
シミュレーション：
デモ画像
モデルの分類
Types of models
• Scale
gap(1000 m2),landscape(1000 km2),region(Global)
• Inclusion of probability distribution
• Grid-based versus Individual-tree-based
• Inclusion of interaction between units
• Inclusion of ecosystem process
目的・用途にあったモデル選択を！！
Choose one suited to your purpose!
実用例
•
•
•
•
収穫予測，森林経営の補助
気候変動下の森林の応答予測
過去の植生推測
撹乱後のreforestation補助
シミュレーション結果：
幹直径階
シミュレーション結果：
森林蓄積変化
実際にやってみられなかった
I gave up simulating…
Required parameters
Number of Timesteps
Random Seed
Number of years per timestep
"Plot Length in the X (E-W) Direction, in meters"
"Plot Length in the Y (N-S) Direction, in meters"
"Plot Latitude, in decimal degrees"
"Mean Annual Precipitation, mm"
Seasonal Precipitation
Water Deficit
"Mean Annual Temperature, degrees C"
Annual Nitrogen Deposition
Plot title
Parameter Name
New Seedling Diameter at 10 cm
Minimum Adult DBH
Max Seedling Height (meters)
Initial Density (#/ha) - 0-1.0 cm DBH
Parameter Name
Adult Height-Diameter Function
Sapling Height-Diameter Function
Adult Crown Radius-Diameter Function
Sapling Crown Radius-Diameter Function
Adult Crown Height-Height Function
Sapling Crown Height-Height Function
Seedling Height-Diameter Function
Slope of DBH to Diameter at 10 cm Relationship
Intercept of DBH to Diameter at 10 cm Relationship
"Maximum Tree Height, in meters"
Slope of Asymptotic Height
Slope of Height-Diameter at 10 cm Relationship
Slope of Asymptotic Crown Radius
Crown Radius Exponent
Maximum Crown Radius (Standard) (m)
Slope of Asymptotic Crown Height
Crown Height Exponent
Parameter Name
Beam Fraction of Global Radiation
Clear Sky Transmission Coefficient
First Day of Growing Season
Last Day of Growing Season
Number of Azimuth Sky Divisions for Quadrat Light Calculations
Number of Altitude Sky Divisions for Quadrat Light Calculations
"Minimum Solar Angle for Quadrat Light, in rad"
"Height at Which GLI is Calculated for Quadrats, in meters"
Height of Fisheye Photo
Number of Azimuth Sky Divisions for GLI Light Calculations
Number of Altitude Sky Divisions for GLI Light Calculations
"Minimum Solar Angle for GLI Light, in rad"
Amount Canopy Light Transmission (0-1)
Parameter Name
Adult Constant Area Growth in sq. cm/yr
Asymptotic Diameter Growth (A)
Slope of Growth Response (S)
Relative Michaelis-Menton Growth - Diameter
Exponent
Parameter Name
"DBH of Maximum Senescence Mortality Rate, as an
integer in cm"
Mortality at Zero Growth
Light-Dependent Mortality
Senescence Mortality Alpha
Senescence Mortality Beta
"DBH at Onset of Senescence, in cm"
Adult Background Mortality Rate
Juvenile Background Mortality Rate
Parameter Name
Seed Distribution
"Minimum DBH for Reproduction, in cm"
Canopy Function Used
Weibull Canopy Annual STR
Weibull Canopy Beta
Weibull Canopy Theta
etc…
シミュレーションの問題点(1)
Problems in simulation
• Conflicts between resolution and scale
What if global warming were simulated based on
individual-tree model?
→more time and machine power would be needed
→accumulation of errors
シミュレーションの問題点(2)
Problems in simulation
• model result verifications
How to assure result from model is right?
Option 1:comparing with field data
→ temporal or spatial series data is necessary
Option 2:simulating with several parameter sets
→commonly used, but still problematic
ご静聴ありがとうございました
• 参考文献
Review of forest landscape models:Types,methods,
development and applications
Acta Ecologica Sinica (2009)

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