Ecological Benefit Assessment Of Urban Forests In Guangzhou

It has been widely recognized that urban forest could provide ecological and environmental services and thus an useful instrument to tackle with the urban environment degradation caused by the rapid urbanization processes. However, it is critically important to make accurate assessment of ecological benefits provided by urban forest to implement sound urban forestry projects and urban forestry policy.Beginning with the analysis on category and character of forest ecological benefits, the thesis compares three kinds of theoretical basis of ecological benefits evaluation. Then according to the marginal utility theory, the thesis discusses five methods of evaluation and establish the models of quantification. Based on the theory of marginal utility value and the models, the thesis evaluates five important benefits: water storage, soil erosion protection, balance of oxygen and carbon dioxide, air decontamination and organism protection. The thesis putted attention on ecological function of forest. It is just the new point of the paper.It is concluded:(1)The ecological benefits in 2005 was calculated: the total value or 8 areas of Guangzhou is 16500 million Yuan. (water storage: 69.8milliom, soil erosion protection: 498.8million, balance of oxygen and carbon dioxide:15722million, air decontamination:183.3million and organism protection:39.3million.)(2)The overall arrangement of urban forests should be directed against ecological problems.(3)The benefit is not proportionate with the rate of coverage of forest, so it is important to improve the ecological function of forest and arrange the forest distribution.