文献类型：期刊文献

英文题名：Nonlinear Simultaneous Equations for Individual-Tree Diameter Growth and Mortality Model of Natural Mongolian Oak Forests in Northeast China

作者：Ma, Wu[1,2] Lei, Xiangdong[1]

第一作者：Ma, Wu

通信作者：Lei, XD[1]

机构：[1]Chinese Acad Forestry, Inst Forest Resource Informat Tech, Beijing 100091, Peoples R China;[2]W Virginia Univ, Sch Nat Resources, Morgantown, WV 26505 USA

年份：2015

卷号：6

期号：6

起止页码：2261-2280

外文期刊名：FORESTS

收录：;EI(收录号：20152700987939);Scopus(收录号：2-s2.0-84933567742);WOS:【SCI-EXPANDED(收录号:WOS:000357157300028)】；

基金：This work was supported by the National Twelfth-Five Year Research Program of China (Grant No. 2012BAD22B0201).

语种：英文

外文关键词：Individual tree diameter growth model; mortality model; weighted regression; nonlinear three-stage least squares; seemingly unrelated regression

摘要：A nonlinear equation system for individual tree diameter growth and mortality of natural Mongolian oak forests was developed based on 13,360 observations from 195 permanent sample plots in Northeast China. Weighted regression was used in a distance-independent diameter growth equation for dealing with heterocedasticity. Since diameter growth and mortality models have common predictors including the diameter at breast height (DBH), stand basal area (BA), basal-area-in-larger trees (BAL), and site index (SI), parameters were estimated using nonlinear three-stage least squares (N3SLS) and seemingly unrelated regression (SUR) which accounts for correlations of errors across models. The system equation provided better projection than individual fitting of the equation based on maximum likelihood estimation. Compared with the separate tree growth model, the simultaneous equations using N3SLS and SUR produced more efficient parameter estimation and smaller bias. Furthermore, N3SLS had more accurate projection. Overall, the simultaneous model will facilitate the growth and yield projection for better management of Mongolian oak forests in the region.