Effects Of Forest Management And Disturbance On Forest Ecosystem Structure And Function

As the most important elment of terrestrial ecosystems, forest ecosystem provides specific environmental, economic and cultural value for society. Human management is an important external factor affecting the forest ecosystem. Research about forest dynamic change under different kind of forest management in a long time series will help to understand the effect of management on structure and function of forest ecosystem and master the effect mechanism, which is of great importantance for sustainable management of forest both theoretically and realistically.Selecting Southeastern United States Coastal Plain and Piedmont as study area, this paper defined three forest management types using land protected data:multiple-use forestry, preservation and wildness, ecological forestry. Using the forest inventory and analysis database, and forest disturbance and regeneration data devived from TM data, analysed effects of forest management and disturbance on forest ecosystem structure and function, draw the following conclusions:1. Forest management and disturbance affected tree species diversity.Tree species diversity and forest disturbance intensity were positively correlated. On the ability to maintain and enhance the species diversity, the ecological forestry was the highest, followed by multiple-use forestry, preservation and wildness was the worst.2. Forest management and disturbance affected the age structure.Age structure and forest disturbance interannual fluctuation were closely related. Age structure of preservation and wildness was in steadily mature trend with minimum annual fluctuation. Age structure of multiple-use forestry was in younger trend with maximum annual fluctuation.3. Forest management and disturbance affected forest volume. On volume per unit area, the highest ecological forestry, wilderness protective lowest,and there was a significant positive correlation between tree species diversity and volume per unit area. On net production capacity, multiple-use forestry was the most stable, wilderness protection had the biggest annual fluctuation, and ecological forestry was steadily increased. Removals and intensity of human disturbance were positively correlated. Mortality was closely related to the natural disturbance intensity.4. The disturbance area and removals of multiple-use forestry were both decreased,indicated that the forest productivity function was gradually weakened, and recreation recreation and ecological functions were being paid more attention. The disturbance area and removals of preservation and wildness forestry were in declining trend, indicated the protected efforts intensified.5. Impacts on forest ecosystem of different forest management had their own characteristics, mainly due to human disturbance level and ways. Although the study areas of this paper are some national forests,state forests,nature reserves and wilderness in southeast coastal area of US, it is still of guidance and reference significance for our country’s forest management, particularly for the management of protected forest areas.