湖北省杉木生长模型研究

The Growth Model of Cunninghamia lanceolata in Hubei

建立湖北省杉木树高、胸径、材积生长模型,为研究湖北省杉木生长情况提供参考。在湖北省3个主要杉木栽培区域的人工林中开展标准地调查,获取283株解析木数据,根据区域特征引入哑变量,分别建立杉木树高、胸径和材积生长模型。结果显示,加入哑变量的Richards方程拟合树高和胸径生长效果最好,未加哑变量的Richards方程拟合材积生长效果较好,模型拟合优度R2分别达到0.8376、0.7946和0.7532。对模型进行独立样本检验,含有哑变量的树高、胸径模型和未加哑变量的材积模型的预估精度均在97%以上。利用模型绘制生长曲线,湖北杉木的树高和胸径速生期在4~12年,并在第7年生长增速达到最大值,材积在第15年之前生长最迅速。鄂西南区域杉木的树高和胸径生长量均略高于鄂东南和鄂西北区域,鄂东南和鄂西北2个区域之间无明显差异。

The growth model of height, diameter at breast height and volume of Cunninghamia lanceolata was established to study the growth of C. lanceolata in Hubei Province. The temporary sample plots of C. lanceolata plantations in three regions of Hubei were investigated and the analytical trees were obtained. Based on the data of 283 analytical trees, dummy variable was introduced according to the regional characteristics, and the growth models of height, diameter at breast height and volume of C. lanceolata plantations were established respectively. The results showed that Richards equation with dummy variable fitted the height and DBH growth best, Richards equation without dummy variable fitted the volume growth model better, the goodness of fit R2 of the model reached 0.8376, 0.7946 and 0.7532. The models were tested by independent samples, showing that the prediction accuracy of height model, DBH model and volume model without dummy variables was above97%. According to the growth curve fitted by the model, the fast growth period of height and DBH of C.lanceolata in Hubei was about 4-12 years, and the maximum growth rate was reached in 7 a, and the volume grew fastest before 15 a. The growth of height and DBH of C. lanceolata in southwestern Hubei was slightly higher than that in southeastern and northwestern Hubei, and there was no significant difference between southeastern and northwestern Hubei.