Characteristics of vegetations and soil nutrients on subalpine degraded forestlands in Northwest Yunnan;

In the paper,species composition,species density,dynamic change,and impacts on vegetation regeneration of soil seed pool are introduced;and countermeasures for forest regeneration in degraded forestland by means of soil seed pool are proposed.

As one of the most critical environmental problems in the 21st century, forest degradation has been facing worldwide.

Forest degradation,forest management,devegetation and revegetation are several additional direct human\|induced activities under the Kyoto Protocol 3 4 Their definitions are closely connected to the carbon accounting methodologies and the greenhouse gases (GHGs) emissions and removals of these activities,for which they are the key issues concerned by IPCC and UNFCCC.

The change of soil enzyme activity and relationship between enzyme activity and soil nutrient content during the process of forest degradation were studied to provide the theoretical basis for revegetation in Karst region with the frail ecosystem.

It is an important content of environment construction to enpedite sustainable use of soil and water resources in the mountain area of conversion from farmland to forest.