金子山国有林场4种典型林分空间结构综合评价OA北大核心CSTPCD

[Objective]The objective is to comprehensively evaluate the spatial structure of four forest types in Jinzishan state-owned forest farm in Hubei Province,and determine the main factors affecting the forest stand structure in the region,so as to provide a theoretical basis for improving sustainable forest management level and forest quality.[Method]Based on the measured plot data of evergreen deciduous broad-leaved mixed natural forest,Cunninghamia lanceolata plantation,Cryptomeria japonica var.sinensis plantation and Liriodendron chinense plantation,forest spatial structure indicators such as uniform angle index,neighborhood comparison,mingling degree,and crowding degree were selected,and the unit circle comprehensive evaluation system was applied to comprehensively evaluate the four typical forest types.[Result]The proportion of random individual trees in different types was the highest,and the proportion of trees in different neighborhood comparison degrees was similar on the whole.The overall distribution of trees in the evergreen deciduous broad-leaved mixed natural forest was random[average value of uniform angle index(W)=0.492],and the stand was well mixed[average value of mingling degree(M)=0.747],but the growth advantage of trees was not obvious[average value of neighborhood comparison(U)=0.497],the canopy was continuously covered[average value of crowding degree(C)=0.941],and the resource utilization rate was high.Other plantations also showed a trend of random distribution(W=0.505-0.514)or slight cluster distribution(W=0.529),and the degree of mixing was low.Some trees showed certain advantages,especially in Cunninghamia lanceolata forests.Among the three types of plantations,the trees in L.chinense plantations were in a very dense state(C=0.768),while the stands of Cunninghamia lanceolata(C=0.557)and Cryptomeria japonica var.sinensis(C=0.563)plantations were in a relatively dense state,and there was still some growth space for trees.The comprehensive evaluation index of spatial structure showed that the state of evergreen deciduous broad-leaved mixed natural forest(0.600)was better than that of Cunninghamia lanceolata(0.583),Cryptomeria japonica var.sinensis(0.521)and L.chinense plantations(0.487).[Conclusion]There are differences in stand structure of different origins in the same region,and the spatial structure of evergreen deciduous broad-leaved mixed natural forest is better than that of Cunninghamia lanceolata,Cryptomeria japonica var.sinensis and L.chinense plantations.[Ch,2 fig.6 tab.37 ref.]