Influence of the Spatial Structure of tress,etc. on the Young Trees of Pinus koraiensis under Natural Secondary Forest

Impacts of 6 environmental factors (light condition,direct sunlight,thickness of soil humus,neighboring trees,upper canopy species,herbs and shrubs) on growth of young trees of Pinus koraiensis were investigated on young trees of P.koraiensis and 4 closest neighboring trees which were considered the structural unit of the individual growth environment.Influence of 3 factors of light condition,thickness of soil humus and neighboring trees were introduced in this paper.Results indicated that: (1) The parameter of Opening degree (K)of neighboring trees could be used to indicate the special requirement for light environment by the young individual trees of P.koraiensis.Along with the growth of neighboring trees,Opening degree of them to the young individual trees of P.koraiensis would decrease.(2)The thickness of soil humus (more than 20 cm) was favored the growth of young trees of P.koraiensis.(3)Mingling (M) and Neighborhood pattern(W) could be used to respectively reflect changes of neighboring trees and relative position to the young trees of P.koraiensis.When M=0.5 (medium mixture),W=0.5 (random),i.e.the associated trees were P.koraiensis and the neighboring trees were stochastic distribution,it was favor the growth of P.koraiensis.