Spatial Structure And Optimization Models Of Cunninghamia Lanceolata In Jiangle Forestry Farm

Cunninghamia lanceolata plantations in Jiangle Forestry are mostly Timber. Although economic benefits is the main business objective, there is a growing emphasis on comprehensive benefits of forests in recent years, especially after the reform of forestry. Therefore, how to manage Cunninghamia lanceolata plantations rationally so that multiple functions of forests can be use fully is particularly important.In this study, Voronoi diagram was used to divide spatial units of trees and analyze spatial structure characteristics of forests. Then spatial optimization model of selective cutting and spatial optimization model of replanting were established to determine spatial units what need to be regulated. And the optimization results were evaluated. The main conclusions are as follows:(1) There are 9 different structure units of Cunninghamia lanceolata plantations in Jiangle Forestry. The range of the number of nearest neighbor trees is 3 to 11.5,6,7 are most common and 6 accounts for the largest proportion.(2) The spatial structure characteristics of Cunninghamia lanceolata plantations in Jiangle Forestry are:The degree of segregation among tree species was not high and in the medium mixed state and it decreases with increasing stand age. The differentiation of DBH was not significant, which indicates a middle level of competition. Competition index of each species are quite different. And Cunninghamia lanceolata occupies a dominant position only in the competition of sapling forest. The individuals of tree displayed a uniform distribution pattern. The degree of difference between spatial structure indexes based on Voronoi diagram and calculated in traditional methods is acceptable. The spatial structure indicators based on Voronoi diagram are valid.(3) The composite spatial structure index of all stands are generally low. Stand spatial structure is irrational and is in urgent need of improvements. Stand spatial structure can be improved by spatial optimization model of selective cutting and spatial optimization model of replanting and the spatial structure of adjusted stands are more rational and stable.