福州市湿地松人工林树皮厚度模型研究

以湿地松样木观测数据为基础，运用R软件进行数据分析，采用最小二乘法拟合胸高处树皮厚度、任意高度处树皮厚度、相对树皮厚度和去皮直径这4类树皮厚度模型，并对模型进行优选。结果表明：筛选出4个模型分别用于拟合胸高处树皮厚度、任意高度处树皮厚度、相对树皮厚度和去皮直径，模型表达式依次为BBT=0.372 + 0.049DBH、BT=0.964 - 0.676CR - 0.055RH + 0.034dob、RBT=0.095 + 0.902RD^1.718和dib=0.906dob^0.995。以上4个模型拟合精度高，均不存在多重共线性问题，且模型没有异方差或经过变量变换得到较好的修正。拟合模型所需的数据除了冠长率之外，其余数据在林业生产实践中具有易获取性。在树皮厚度模型中加入冠长率，对于湿地松而言，拟合效果较好。

Bark Thickness Model of Pinus elliottii Plantation in Fuzhou

Based on the data of Pinus elliottii, R software was used to analyze the data. Least square method was used to fit the bark thickness at breast height, bark thickness at any height, relative bark thickness and bark diameter, and the model was optimized. The results showed that 4 models were selected to fit the bark thickness at breast height, bark thickness at any height, relative bark thickness and bark diameter. The models were BBT=0.372 + 0.049DBH, BT=0.964 - 0.676CR - 0.055RH + 0.034dob, RBT = 0.095 + 0.902RD1.718 and dib = 0.906dob0.995 respectively. The above 4 models have high fitting accuracy, no multiple collinearity problem, and the model has no heteroscedasticity or has been modified by variable transformation. Besides the crown length rate, the data needed by the fitting model are easy to obtain in forestry production practice. The addition of crown length to bark thickness model is better for slash pine. The study on the bark thickness model of P.elliottii plantation can provide reference for estimating the bark volume, yield and bark growth.