长白山天然云冷杉针阔混交林地位指数导向曲线的模拟

Site Index Guide Curve of Nature Spruce-Fir Coniferous and Broad-Leaved Mixed Stands in Changbai Mountain

用3090株解析木建立云冷杉针阔混交林主要树种的胸径—林龄曲线,根据样地林木胸径估测出林木的林龄,用98块样地来模拟3株优势木平均林龄与平均树高的关系,并构建3种地位指数导向曲线,从决定系数、相对平均误差和均方根误差3个方面对导向曲线进行检验。结果表明:1)10个树种的胸径—林龄最优关系曲线为抛物线方程、指数方程和幂方程;2)分树种选择云冷杉上层优势木构建的地位指数模型精度,高于不分树种选择样地优势木构建的地位指数模型;3)构建的3参数地位指数导向曲线模型优于两参数导向曲线;4)同等地位指数级下,不同树种生长差异显著。

With 3090 analytic trees, the experiment was conducted to build the age-diameter at breast height （A-D） curves ot the main tree species in the nature spruce-fir coniferous and broad-leaved mixed stands, and forecast the age of trees ac- cording to the diameter of trees in the sample plot. Three kinds of guide curve of site index was formulated with 98 sample plots to simulate the relationship between the average age and average height of three dominant trees. Coefficient of deter- mination （R2） , mean relative error （MRE） and root mean squared error （RMSE） were selected to analyze the validity of this equation. The optimal curve of ten species is a parabolic equation, exponential equation and power equation. The model accuracy of site index by distinguishing tree species to choose the dominant tree of spruce-fir is higher than that by choosing the dominant tree of sample plot without distinguishing tree species. The site index curve model of three-parame- ter equation is superior to that of two-parameter. There is significant difference of tree growth in the same site index.