湖南省主要树种单木和林分生长率模型研建

Developing Tree and Stand Level Growth Rate Models for Dominant Tree Species in Hunan Province

以湖南省1999年、2004年、2009年和2014年4期的森林资源连续清查为基础,利用大量、连续、系统的固定样地和样木数据,根据胸径和生长率的一般分布规律,选取常用的生长率回归方程作为基础模型式,采用非线性回归估计方法,构建了11个树种组的单木胸径生长率和材积生长率模型,以及9个树种组的林分蓄积量生长率模型。结果表明:各模型确定系数R~2均在0.88以上,单木生长率模型的总体相对误差和平均预估误差均在4%以内,胸径生长率模型的平均预估误差大部分在10%以内;林分蓄积量生长率模型的平均预估误差和总体相对误差基本在4%以内,蓄积量生长率模型的平均预估误差在20%以内。各项指标表明,拟合模型能满足精度要求,具有较高的实用性,可为湖南省森林资源年度更新和森林经营管理提供技术支撑。

Based on the large,continuous,systematic permanent plots measured in 1999,2004,2009,and 2014 in Hunan Province from the national forest resources inventory,selecting the common growth rate regres-sion equation as base model,by nonlinear regression estimation method,tree-level DBH growth rate and volume growth rate model of 11 tree species groups,and stand-level volume growth rate model of 9 tree species groups were developed,according to the general distribution of DBH and growth rate.The results shows:for all mod-els,the determination coefficient R’is above O.88;for tree-level growth rate model,the total relative errors(TRE)and mean prediction errors(MPE)are all less than 4%,and the MPE is mostly within 10%for DBH growth rate model;for stand-level volume growth rate model,the MPE and TRE of are most less than 4%,and the MPE are about 20%for volume growth rate model.Each indicator presents that the model developed in this study can meet accuracy requirements and has high practicability,which can provide technical basis for the an-nual update of forest resources and forest management in Hunan Province.