An Ecological Study for Management of Suburban Forests

近年来，郊区森林已被公认为市民生活的重要环境，但人们对如何管理郊区森林的生态知识却很少。本研究旨在为城郊森林的经营管理提供生态学依据。结果表明：(1)在松林发生松材萎蔫病时，由于地表扰动，枯枝断枝处理发生逆向演替。被破坏的森林被忽视，促进了阔叶林的演替，在这种情况下，如果清除凋落物，松树可以再生。(2)建立了植被变化的系统动力学模型。由于该研究很好地再现了松林遭受松材枯萎病的多个演替品种，将为城郊松林的管理提供有用的信息。(3)生物固氮、矿化和固氮过程只发生在森林土壤系统的表层，支持森林生物量的生产和演替。(4)对凋落物-森林土壤表层有机质的去除和扰动，不仅会导致生物固氮、矿化和氮的固定化明显降低，还会使微生物组成和活性变性，并使土壤胶体发生变化。森林生态系统的生产演替将受到严重干扰。

Recently suberban forests are have been recognized as an important environment for the citizen life, nevertheless there has been few ecological knowledge how to manage them. The aim of this study is to get the ecological bases for the management of the suburban forests. The results are as follows :(1) In pine forests suffered from the pine wilt disease, the treatment of cutting-off of dead stem occurs reverse succession because of the disturbances of forest floor. Damaged forests ignored promote the succession to broad-leaved forests, in this case, pine may regenerate if litter is removed.(2) A system dynamics model on the vegetation changes is developed. As it reappears very well many varieties of succession of pine forests suffered from the pine wilt disease, it will give useful information for the management of suburban pine forests.(3) Biological nitrogen fixation, mineralization and immobilization of nitrogen process occurs only surface part of forest soil system which support the biomass productions and succession of the forest.(4) Removal and disturbance of the litter -surface organic matters of forest soil- occurs not only distinctive decrease of biological nitrogen fixation, mineralization and immobilization of nitrogen but also might denature microbiological composition and activities, besides changes of soil colloids. Consequently productions and succession of forest ecosystem would disturbed profoundly.