Adaptation to CC in African Forests
UNDP Accra
Forest Model
Climate Outcome
Emission Scenario
Timber Response Carbon Response
Economic Outcome
Ecosystem Model
Ecosystem Model
• Predicts boundaries of biomes (grassland, forest, savannah, desert)
• Predicts fire
• Predicts NPP
• Predicts carbon storage
• Predicts how all of the above factors shift with climate change scenario
Timber Model
Volume
Age
Shape of Volume Function
• Almost all life forms are S shaped
• Implies percentage growth rate falls over time (with age)
• Average growth rises over time to maximum and then falls
Percentage growth
% Growth
Age
Interest rate
Economic Model of Timber
• Maximize present value of timber, W
• W=P*V(A,T)exp(-r*A)-C/(1-exp(-rA))
• Optimal age A, maximizes W, and depends on temperature, T, and C is cost of plantation
Climate Change Effects
• Climate change will move boundaries of forest (suitable land)
• Climate change will alter NPP- growth of trees
• Climate change will alter fire frequency
Adaptation
• Harvest trees early if vulnerable to increased chance of fire or if slow growth
• Plant new tree species if will do better during lifetime of tree
• Plant only in land suitable for trees (adapt to changing boundaries of biome)
• More (less) intensity (fertilizer other inputs) if more (less) productive
Suppose CC Reduces Growth
% Growth
Age
Interest rate
Original
New
Including Carbon Storage
• Carbon is captured in body and roots of tree
• Trees take carbon out of atmosphere
• Trees help mitigate greenhouse gas problem
• Carbon is proportional to volume
Impact of including carbon
• If farmers are given an incentive to store carbon, they will include this incentive into their harvest and planting decision
• Carbon payments make forests more profitable (expand forest area) and make longer rotation ages more profitable
Examine case study
• Loblolly pine
• Examine timber alone
• Add carbon benefit
• Introduce CC on timber
• Introduce CC on timber plus carbon
• Assume P=$.15/bdft, C=100, R=.04
• Assume carbon price=$5/ton/yr
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