北京松山自然保护区主要树种冠幅预测模型研究

冠幅作为林业研究的关键因子，开展冠幅的研究对于精准林业发展具有重要意义。为了更好地利用冠幅对树木其他因子进行预测，选取了北京市松山自然保护区油松、白蜡、蒙古栎等14个常见树种作为研究对象，基于6种回归方程，借助样地实测数据分别建立每个树种的胸径 冠幅和树高 冠幅模型，并针对每个树种筛选出的最优方程进行了精度检验。结果表明，研建的14个树种的模型具有较好的拟合精度，决定系数R2绝大多数都大于0.5，其中，核桃的胸径 冠幅模型最高，R2=0.951，树高-冠幅模型R2=0.887，蒙古栎树高-冠幅模型最低，R2=0.506，也超过了0.5。所建模型的精度评价指标具有一定的统计学意义，对北京市松山地区大面积林分参数的预测预估有重要的参考价值。

Study on Crown Prediction Model of Main Tree Species in Songshan Nature Reserve in Beijing

As a key factor in forestry research, the research on crown width is of great significance for the development of precision forestry. In order to better use crown width to predict other factors of trees, 14 common tree species such as Pinus tabulaeformis Carr., Tilia tuan Szyszyl., Quercus mongolica Fischer ex Ledebour in Songshan Nature Reserve of Beijing were selected to establish the DBH crown model and tree hight crown model. Based on the six regression equations and the measured data of plots, the filtered optimal equations for each species were tested for accuracy. The results showed that the model of 14 tree species displayed good fitting accuracy, most of decision coefficients(R2) were greater than 0.5. Among them, the highest R2 belonged to Juglans regia Linn. DBH crown model which was 0.951, and the R2 of Juglans regia Linn. height model was 0.887. The lowest R2 belonged to Quercus mongolica Fischer ex Ledebour tree height model which was 0.506 and also more than 0.5. The accuracy evaluation index of these models in this study provided esstatistical significance and important reference value for the prediction of large area forest parameters in Songshan area of Beijing.