探索林分形高模型的构建与评价方法,可为湖南省青冈栎林分蓄积量的精准测定提供理论依据。以芦头林场和青羊湖林场的青冈栎次生林为研究对象,基于35个样地的1 055株单木实测数据,建立青冈栎次生林一元、二元林分形高模型。由孔兹干曲线推导出青冈栎树高曲线以计算林分条件平均高,基于林分形高与林分平均胸径、林分条件平均高的一元、二元相关关系,选取6个一元模型和8个二元模型,以决定系数(R²)、均方根误差(RMSE)、解释方差(EA)、平均绝对误差(MAE)和模型预估精度(P₁)作为评价指标。经过评估和比较,选定一元林分形高模型为f(D)=2.870 7×D^{0.261 8}、f(H)=2.022 4+0.339 5×H和二元林分形高模型为f(D,H)=0.590 6×exp(-0.008 3×D)×H、f(D,H)=(0.710 2-0.070 1×logD)H和f(D,H)=2.479 9×(D²×H)^{0.109 2}。通过留一交叉验证和配对T检验对模型进行检验,结果显示一元、二元林分形高模型均具有较高的精度和较强的适用性,进一步验证了以林分平均胸径和林分条件平均高构建林分形高模型的方法合理可行,可为其它类型的林分形高模型构建和林分形高表的编制提供示范和参考。

Exploring the construction and evaluation method of the stand form height model could provide a theoretical basis for the precise measurement of stand volume of Quercus glauca secondary forest in Hunan Province.Based on the measured data of 1055 individual trees from 35 plots,we established the univariate form height model and the binary form height model of Quercus glauca secondary forest in Lutou Forestry Farm and Qingyanhu Forestry Farm.The Quercus glauca tree height curve was derived from the Kunze,M.stem curve to calculate the stand condition mean height.Based on the univariate and binary correlations een form height,stand diameter at breast height and stand condition mean height,6 univariate basic models and 8 binary basic models were selected,and the coefficient of determination(R²),root mean square error(RMSE),explained variance(EA),mean absolute error(MAE)and model prediction accuracy(P₁)were used as evaluation indicators.After evaluation and comparison,the univariate form height model was found to be f(D)=2.870 7×D^{0.261 8}、f(H)=2.022 4+0.339 5×H and the binary form height model was f(D,H)=0.590 6×exp(-0.008 3×D)H、f(D,H)=(0.710 2-0.070 1×logD)H and f(D,H)=2.479 9×(D²×H)^{0.109 2}.The models were tested through cross Leave-One-Out Cross-Validation and Paired T-test.The results showed that both univariate and binary stand form high models had high accuracy and strong applicability.It verified that the method of constructing a stand form height model based on the stand mean diameter at breast height and the stand condition mean height is reasonable and feasible.It can also provide demonstration and reference for the construction of other types of stand form height models and the preparation of stand form height tables.