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应用生态学报 ›› 2016, Vol. 27 ›› Issue (8): 2429-2437.doi: 10.13287/j.1001-9332.201608.026

• 目次 • 上一篇    下一篇

基于抚育间伐效应的落叶松人工林直径分布动态模拟

王蒙, 李凤日   

  1. 东北林业大学林学院, 哈尔滨 150040
  • 收稿日期:2016-02-01 发布日期:2016-08-18
  • 通讯作者: * E-mail: fengrili@126.com
  • 作者简介:王蒙,男,1987年生,博士研究生.主要从事林分生长与收获模型研究.E-mail:36664217@qq.com
  • 基金资助:
    本文由国家科技支撑计划项目(2015BAD09B01)和中央高校基本科研业务费专项(2572014AA29)资助

Modeling the diameter distribution of Larix olgensis plantation based on thinning effects.

WANG Meng, LI Feng-ri*   

  1. College of Forestry, Northeast Forestry University, Harbin 150040, China
  • Received:2016-02-01 Published:2016-08-18
  • Contact: * E-mail: fengrili@126.com
  • Supported by:
    This work was supported by the National Science and Technology Supporting Programs (2015BAD09B01) and the Fundamental Research Funds for the Central Universities (2572014AA29).

摘要: 基于黑龙江省孟家岗林场长白落叶松人工林5块固定样地(其中1块为对照样地,4块为抚育间伐样地,断面积强度为3.7%~49.7%)1974—2014年(林龄为19~59 a)复测的31次胸径数据,采用三参数Weibull分布函数拟合5块样地各年份直径分布,研究了直径分布曲线随林龄的动态变化规律,并分析了抚育间伐对林分直径分布曲线及Weibull分布参数的动态影响.构建了基于抚育间伐效应的Weibull分布参数预测的联立方程组模型,分别采用三阶段最小二乘法及度量误差法估计了模型的参数.结果表明: 未间伐林分(对照)直径分布曲线随林龄增加由“高峰狭窄”(林木直径分布集中)状态逐渐向“低峰宽广”(林木直径分布分散)状态过渡;抚育间伐后,林木直径分布曲线均较抚育间伐前右偏加剧,峰度变高,径阶变窄,对称性下降;间伐强度越大,伐除的中小径阶树木越多,直径分布曲线较间伐前左侧截尾明显,峰度增高,径阶分布范围变小.低强度抚育间伐使得参数a值变大,b值变小,对参数c的影响不明显;高强度抚育间伐使得参数a的增量变大,b值变小,参数c值变小.参数预测联立方程组模型的拟合结果表明,参数b的预测模型拟合效果最好,R2>0.98;参数c预测模型拟合效果稍差,但R2>0.91;三阶段最小二乘法拟合结果与度量误差联立方程组方法区别不大,两种方法检验结果均较好,模型精度都>97%,拟合效率均>0.92.所建立的模型能够较好地模拟抚育间伐效应下落叶松人工林直径分布动态变化,为科学合理经营森林提供了依据.

Abstract: In 1974, five permanent sample plots of Larix olgensis plantation were established in Mengjiagang forest farm in Heilongjiang Province, which included one control plot and four thinning plots with different thinning treatments (remove 3.7%-49.7% of the basal area). Diameter at breast height (DBH) for each tree (19-59 a) of the five plots was remeasured 31 times from 1974 to 2014. The three parameters Weibull function was used to describe the DBH distribution of different ages for the five plots. The dynamic changes and the effects of thinning on the diameter distribution curves and the three parameters of Weibull function were analyzed. Based on the thinning effects, the parameter prediction model (PPM) of simultaneous equations system was developed and the parameters were estimated by three-stage least squares method (3SLS) and error-in-variable method of simultaneous equations. The results showed that the diameter distribution curves with stand age changed from higher peak with narrow DBH range to lower peak with large DBH range for unthinned stand (control plot). For thinning plots, the skewness was more right-hand with higher peak, narrow DBH range, and increased asymmetry of the curves after thinning. Increasing with thinning intensity, more trees of small or middle sizes were cut and the curves of diameter distribution were obvious left-truncted higher peak with narrow DBH range than before thinning. The parameter a of the Weibull function increased with thinning intensity and the parameter b decreased. The parameter c was not influenced by lower intensity thinning, but decreased by higher thinning intensity. The fitting results for the PPM of simultaneous equations system showed that predicting models for the parameter b were best (R2>0.98) and the R2 for model of the parameter c was larger than 0.91. The method of 3SLS was as good as the error-in-variable method, and there was no significant diffe-rence. The results of validation for the two methods showed that, the precision of the three prediction models was >97%, and the fitting efficiency (EF) was >0.92. The parameter prediction mo-dels developed based on the effects of thinning performed well and could be used to predict the dynamic change of diameter distribution and to provide suitable management of L. olgensis plantation.