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