关键词: 三峡库区, 坡耕地, 种植制度, 水土保持

Abstract: Neighborhood comparison is defined as the proportion of the nearest greater neighbors to a given reference tree measured by a certain variable.By this way,the dominant differentiation degree of individual wood could be measured well.In this paper,the variables DBH,biomass,canopy breadth,and tree height were used to make the neighborhood comparison of Cryptomeria fortunei plantation in Chongzhou forest farm.The results showed that the neighborhood comparison measured by DBH and biomass had a slight fluctuation range and the highest reliability.Nevertheless,due to the effects of various tree types,the neighborhood comparison measured by canopy breath and tree height was not as reliable as that measured by the former two variables.The average value of the neighborhood comparison measured by DBH and biomass was visibly higher than that by canopy breath and tree height,indicating that the differentiation degree of individual’s DBH and biomass was further greater than that of individual’s canopy breath and tree height.It was possible that increasing individual’s DBH to enhance its biomass,and thus,to achieve its predominance status among individuals’ competition was the main strategy of individual’s differentiation. Neighborhood comparison should also be taken as an instructive reference in modifying the spatial structure of stand.

Key words: Three Gorges reservoir area, Slope cultivated land, Cropping system, Soil, water conservation