Modeling the Marginal Value of Rainforest Losses : A Dynamic Value Function Approach

Strand, Jon

World Bank, Washington, DC

关键词: FOSSIL FUEL;    ECOSYSTEM;    LANDSCAPE ECOLOGY;    FOREST FRAGMENTATION;    ISSUES;   

DOI  :  10.1596/1813-9450-7445
RP-ID  :  WPS7445

学科分类：社会科学、人文和艺术（综合）

来源: World Bank Open Knowledge Repository

【 摘 要 】

A rainforest can be modeled as a dynamicasset subject to various risks, including risk of fire. Anysmall part of the forest can be in one of two states: eitheruntouched by forest fire, or already damaged by fire, inwhich case there is both a local forest loss and increaseddryness over a broader area. In this paper, two Bellmanequations are constructed, one for unharmed forest and asecond for already burnt forest. The analysis solves the twoequations for the total expected asset values in each of thetwo states, assuming that asset returns have a constantgrowth rate over time. The equations are used for derivingthe marginal value of standing (unburnt) rainforest,equivalent to the expected discounted value loss when losinga small additional forest patch. The paper shows thatmarginal forest value is increased by the additional drynessand forest fire risk that follow from forest fragmentationwhen additional forest is lost locally. Both forest firesand dryness here serve as “multipliers” to the basicservices return loss, within and outside the forest. Thepaper also presents a framework for calibrating the impactof the forest fire risk component on forest value.