Study On The Spatial Pattern And Optimization Status Of Different Succession Stages Of Larix Principis-rupprechtii

In this study,the main stand types of Larix principis-rupprechtii natural forests in Pangquangou Nature Reserve were selected as the research objects and the following six plots were selected:(1)Pure Larix principis-rupprechtii forest,abbreviated as LC.(2)North China larch spruce poplar mixed forest,referred to as LPP.(3)North China Larch and Birch mixed forest,referred to as LBP1.(4)North China larch white birch spruce mixed forest,referred to as LBP2.(5)North China larch white birch spruce mixed forest,referred to as LBP3.(6)Birch North China larch spruce mixed forest,referred to as BLP.Evaluate and analyze the spatial pattern and stand status of larch at different succession stages by means of stand uniform angle index(W),neighborhood,comparison(U)mingling(M)and state evaluation.The main results were as follows:(1)The plot angle scales of LC and LBP2 samples are 0.457 and 0.42 respectively,while the spatial distribution pattern of stand is uniform;the plot angle scales of LPP,LBP1,LBP3 and BLP samples are 0.528,0.586,0.587 and 0.5 respectively,which are random distribution,and the horizontal structure of stand is developed from uniform distribution to random distribution.The mingling of LC,LPP,LBP1,LBP2,LBP3 and BLP plots were 0.55,0.422,0.409,0.6 and 0.716,respectively.With the succession,the isolation degree of the populations increased and the mingling state between weak degree and moderate degree developed into intensive mingling state.The neighborhood comparison were 0.5,0.471,0.5,0.511,0.488 and 0.433 respectively,and the whole plots were in the state of golden mean,with no significant difference in size differentiation and overall equilibrium.(2)The ω values of LPP and LBP1 plots are 0.542 and 0.418 respectively,and the evaluation results of stand status are ordinary;the ω values of BLP,LBP3 and LC plots are 0.394,0.393 and0.353 respectively,while the evaluation results of stand status are relatively poor;the ω values of LBP2 plots are 0.209 and the evaluation results of stand status are extremely poor.