Abstract:

The functions and values of water conservation，soil reinforcement and fertility maintenance of the urban forest in Guangzhou were assessed. The results showed that the urban forest ecosystem in Guangzhou city could store 6.429×10.8 m³ water and adjust 2.609×10.8 m³ flooding more than that of nonstocked land. The plant annual net accumulation of nutrient for N was 4.949×10.4 t，for P was 0.428×10.4 t，and for K was 4.400×10.4 t and the nutrients of annual litter fall returned back to forestland were that for N was 3.524×10.4 t，for P was 0.216×10.4 t and for K was 1.539×10.4 t; The urban forest in Guangzhou city also could reduce soil loss in the amount of 123×10.4 t，reduce organic matter loss in the amount of 3.905×10.4 t including 0.218×10.4 t N，0.066×10.4 t P and 2.368×10.4 t K; The economic function effect of the system for water storage was 1.286×10.8 yuan，for flooding prevention was 0.522×10.8 yuan，for fertilizer maintenance was 3.497×10.8 yuan，for soil reinforcement was 1.145×10.8 yuan and for soil improvement was 1.872×10.8 yuan. So that the annual urban forest economic function value in Guangzhou city in the areas of water conservation，soil reinforcement and fertilizer maintenance was 8.322×10.8 yuan.

Key words: urban forest, water conservation, soil reinforcement, fertilizer maintenance, economic evaluation