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作 者 ：张雄清,雷渊才

期 刊 ：林业科学研究 2009年 22卷 6期 页码：824-828

关键词：直径年生长量；存活率；固定生长率法；可变生长率法；

Keywords:annual diameter growth, survival probability, constant rate method, variable rate method,

摘 要 ：采用北京山区油松定期调查数据,比较研究固定生长率法和可变生长率法建立的单木直径年生长量模型和年存活率模型。研究结果表明:利用可变生长率法建立的直径生长模型中,平均偏差(-0.005 9)、平均绝对偏差(0.779 1)、均方根误差(1.038 4)分别比固定生长率法的平均偏差(0.097 5)、平均绝对偏差(0.920 0)、均方根误差(1.198 3)小,而且其决定系数(0.949 3)也高于固定生长率法的决定系数(0.917 8);在单木存活率模型中,可变生长率法的平均偏差(8.59E-7)、平均绝对偏差(0.088 4)、均方根误差(0.211 7)也分别比固定生长率法的平均偏差(0.002 7)、平均绝对偏差(0.091 1)、均方根误差(0.212 1)小,并且其对数似然值(-4 137.240 0)也比固定生长率法的对数似然值(-4 230.320 0)大。因此,利用可变生长率法建立的单木生长模型预测精度比利用固定生长率法建立的单木生长模型预测精度高,因为前者考虑了林分因子(林分断面积,林分优势高)和单木因子在生长期间的变化引起的单木直径年生长量及存活率的变化。

Abstract:The inventory data of the Chinese pine (Pinus tabulaeformis) in Beijing Mountains were used to establish and compare individual tree diameter growth and survival models with constant rate method and variable rate method. Results showed that in the individual-tree diameter growth model, MD was -0.005 9, MAD 0.779 1, RMSE 1.198 3 and R² 0.949 3 based on the variable rate method. But with the constant rate method, they were 0.097 5, 0.917 8, 1.198 3 and 0.917 8 respectively. In the survival model, MD was 8.59E-7, MAD 0.088 4, RMSE 0.211 7, and LogL-4 137.240 0 using the variable rate method. But with the constant rate method, they were 0.002 7, 0.091 1, 0.212 1, and -4 230.320 0 respectively. The variable rate method out-performed the constant rate method in predicting future individual tree survival and diameter growth because the former accounted for the variable rate of annual diameter growth and tree survival probability, which were caused by changes of stand (basal area, dominant height) and tree attributes.

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