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采用乘除法对全混交度、林层指数、W_V_Hegyi竞争指数、角尺度、开敞度5个林分空间结构参数进行多目标规划,确定林分空间结构优化目标函数,以林分空间结构和非空间结构为约束条件,在采用综合灰色关联度分析法确定林分空间结构约束条件优先次序的基础上,构建杉木生态林林分间伐空间结构优化模型,并将该模型用于确定样地中最该采伐的林木。结果表明:杉木生态林林分空间结构优化目标函数值与相关的空间结构指数的灰色综合关联度排序依次为全混交度(0.7016)>林层指数(0.7008)>角尺度(0.6578)>开敞度(0.5960)>W_V_Hegyi竞争指数(0.5785),因此在进行林木单株间伐前考虑林分空间结构约束条件时,首先要考虑林分的混交度,其次是林层指数;将构建的模型用于研究样地(20 m×30 m)确定的最优间伐木为14株,间伐强度为14.1%,间伐后描述林分非空间结构的径阶数和树种数均未减少,保持原有的径阶个数和树种个数;间伐后林分全混交度提高2.71%,林分树种空间隔离程度得到提高;林分林层指数提高10.91%,林分垂直分层结构有较大幅度的改善;林分W_V_Hegyi竞争指数降低8.64%,林分中林木所受的竞争压力减小;林分|角尺度-0.5︱降低8.25%,林分空间分布格局更加趋向于随机分布;开敞度增加了11.98%,林分的透光条件有一定程度的改善,林分空间结构优化模型目标函数Q(g)值提高了12.18%。林分空间结构整体上趋向优化。
Multi-objective planning was carried out on the spatial structure parameters of five mixed stands, such as total mixed degree, forest floor index, W_V_Hegyi competition index, angle scale and openness. The spatial objective function of spatial structure was determined. Spatial structure as the constraint condition, and based on the comprehensive gray relational analysis method to determine the priority order of the spatial structure constraints of the forest, the optimization model of the spatial structure of the forest stand was set up and used to determine the spatial distribution The logging forest. The results showed that the order of gray comprehensive relevancy between the objective function value and the spatial structure index of the spatial structure of the Chinese fir plantation was as follows: total mixed degree (0.7016)> forest index (0.7008)> angle scale (0.6578)> open (0.5960)> W_V_Hegyi competition index (0.5785). Therefore, when considering the constraints of spatial structure of forest stand before thinning, the mixed degree of forest should be considered first, followed by the index of forest layer. The model should be used in The optimal inter-logging density was 14 and the thinning intensity was 14.1% in the study plots (20 m × 30 m). The diameter order and the number of species in the non-spatial structure after the thinning were not reduced, The number of tree species and the number of tree species. After the cutting, the total mixed degree of stands increased by 2.71%, the spatial isolation of tree species improved; the stand index increased by 10.91%, and the vertical stratification of stands significantly improved; The competition index of forest stand W_V_Hegyi decreased by 8.64%, the competition pressure on forest stand decreased; the stand scale -0.5︱ decreased by 8.25%, the distribution pattern of stand spatial distribution tended to be random distribution; the open space increased by 11.98 %, The light transmission of the forest has a certain degree of improvement, Lin Spatial structure optimization model function Q (g) is increased by 12.18%. The spatial structure of the stand tends to be optimized as a whole.