Abstract:Urban forestry, developed from the fusion of forestry and landscape architecture, is an industry of setting up and managing urban forest ecosystem,which builds, manages and utilizes the biocenose-mainly the trees,and the facilities in cities. Urban forestry ecosystem is a subsystem under the urban compound ecosystem, which broadly participates in the use of substance and energy of the urban compound ecosystem, the coordinative development of society and nature, and the self-balanceing of the system.Urban foresty is a science of studying urban forestry ecosystem, construction, management and utilization of urban forest. The tasks of this science are those of making plannes, designs for urban forestry, studying utilization and effects of urban forestry, providing relative basis for legislation, constructing kinds of forest types, plant communities and landscapes, and selecting and producing plant materials.