Comparative Study on the Mixed Degree of Different Forest Types in Linan

According to the plot data of forest resources monitoring in Linan District in 2004, the mixed degree based on Voronoi diagram was combined with variance analysis to compare the mixed degree of different forest types in Lin'an District. Results show that at the individual level, the mixed grades of plantation and natural forest are from coniferous forest, broad-leaved forest and coniferous and broad-leaved mixed forest. In the natural coniferous forest, due to the same species aggregation of Cunninghamia lanceolata and Pinus massoniana, the proportion of Cunninghamia lanceolata and Pinus massoniana mixed at zero and low in single wood is 71.9%. In the artificial coniferous forest, Cunninghamia lanceolata mixed in the single wood accounts for 91.14%; in the artificial broad-leaved forest, there existed pure Carya cathayensis forest, and the proportion of Carya cathayensis in the single-wood zero-degree mixed is as high as 95.56%. At the forest level, there is no strong mixed phenomenon in each forest type. Among the natural forests and plantations, coniferous and broad-leaved forests have higher forest standpoints than coniferous and broad-leaved forests, and the range of mixed degree ranges is relatively concentrated, indicating that the mixed species of coniferous and broad-leaved mixed forests are highly isolated. In the artificial broad-leaved forest, the zero-degree mixed forest stands all in the pure Carya cathayensis forest; in the artificial coniferous forest, the low-degree mixed forest stands are mainly pure Cunninghamia lanceolata; the mixed mixed proportion of artificial coniferous and broad-leaved mixed forest is 80%. It is mainly a mixed forest composed of Pinus taiwanensis, Pinus massoniana, Cunninghamia lanceolata and other soft broad-leaved tree species.