Spatial Structure Characteristic of Platycladus orientalis Forests in Beijing Xishan Mountain

This study investigated the application of terrestrial laser scanning for providing quantitative forest parameters at the plot-level by using 'multi-stop' scanning method for determining stand parameters such as the tree height,diameter,basal area,and other parameters.This paper described the spatial structural characteristics of one plot-level stand of Platycladus orientalis forests in Beijing Xishan mountain using mingling degree,neighborhood comparison and uniform angle index.The results showed that there were twenty-one species in arbor layer of Platycladus orientalis forests,among which,Platycladus orientalis had the obvious advantage in population density and basal area,being the dominant and constructive species of the tree layer.The average mingling degree of the whole stand was 0.261,suggesting the low mingling degree of stands.The dominant species such as Platycladus orientalis,Robinia pseudoacacia and Rhus typhina population were mainly none or less-mixed,accounting for 85%,58%,57% of the total plants of the populations,while the accompanying species generally presented moderate,intensity and high intensity.In the spatial structural units,Platycladus orientalis,Pinus tabulaeformis,Quercus variabilis,Acer truncatum and Robinia pseudoacacia were mainly dominant,sub-dominant,and intermediate trees,accounting for 57 %,67%,89%,66% and 71% of the total plants of the populations,respectively,while the advantages of other populations were not obvious.The uniform angle index value of Platycladus orientalis forests was 0.542(greater than 0.517),indicating that the spatial pattern of the stands was the aggregative distribution,but the aggregation degree was not high and the aggregation scale was not large.