干旱区研究 ›› 2018, Vol. 35 ›› Issue (5): 1129-1137.doi: 10.13866/j.azr.2018.05.16

• 生物及生物资源 • 上一篇    下一篇

樟子松人工固沙林冠幅—胸径模型

韩艳刚1, 雷泽勇1, 赵国军2, 周晏平1, 徐畅1   

  1. 1.辽宁工程技术大学环境科学与工程学院,辽宁 阜新 123000;
    2.辽宁省固沙造林研究所,辽宁 阜新 123000
  • 收稿日期:2018-01-02 修回日期:2018-02-02 出版日期:2018-09-15 发布日期:2025-11-18
  • 通讯作者: 杨建军.E-mail:yjjdfly@sina.com
  • 作者简介:韩艳刚(1991-),男,硕士研究生,研究方向为森林生态工程. E-mail: hyghan@163.com
  • 基金资助:
    国家自然科学基金地区基金项目“基于多核素联合示踪的干旱区风蚀对有机碳的影响研究”(41661057)资助

Canopy-DBH Models for Sand-fixing Plantation of Pinus sylvestris var.mongolica

HAN Yan-gang1, LEI Ze-yong1, ZHAO Guo-jun2, ZHOU Yan-ping1, XU Chang1   

  1. 1. College of Environmental Science and Engineering,Liaoning Technical University,Fuxin 123000,Liaoning,China;
    2. Liaoning Province Institute for Sand-fixation and Afforestation Research,Fuxin 123000,Liaoning,China
  • Received:2018-01-02 Revised:2018-02-02 Published:2018-09-15 Online:2025-11-18

摘要: 基于章古台地区22块樟子松(Pinus sylvestris var. mongolica)人工纯林标准地的702棵樟子松立木数据,构建了樟子松固沙林冠幅—胸径关系的基础模型、广义模型及基于混合效应的基础模型和广义模型;比较了随机选择样本木、选择平均胸径树、选胸径较小树和选胸径较大树4种方案,计算混合模型随机参数时的混合模型预测精度;最后分析了不同林木因子和林分变量对冠幅—胸径关系的影响。模型评价指标包括决定系数(R2)、平均绝对误差(MAE)以及均方根误差(RMSE)。结果表明:枝下高(HCB)、相对植距(RS)和林龄(A)对冠幅—胸径关系影响最为显著;混合模型拟合精度(基础混合模型R2、MAE和RMSE分别是0.703 0、0.386 6和0.515 4;广义混合模型R2、MAE和RMSE为0.705 1、0.382 2和0.513 6)高于最小二乘法回归(OLS)模型(基础模型R2、MAE和RMSE分别为0.587 5、0.469 6、0.607 5;广义模型R2、MAE和RMSE分别为0.661 8、0.415 5和0.550 0)。基础混合模型和广义混合模型差异较小(2模型R2、MAE和RMSE均相差1%左右)。冠幅随HCB和A的增大而减小,随RS的增大而增大。进行冠幅预测时,推荐使用基础混合模型并从每块标准地选择2棵平均木冠幅计算其随机参数,或使用方法较为简单的OLS广义模型预测单木冠幅大小。

关键词: 樟子松, 人工固沙林, 冠幅—胸径, 混合效应, 基础模型, 广义模型

Abstract: In this study,the data consisted of 702 individuals of Pinus sylvestris var.mongolica in 22 temporary sample plots of pure plantation in Zhanggutai of Liaoning Province,northeast China,were used to develop the canopy-DBH models,i.e.the basic model (fitted by ordinary least squares,OLS),generalized model (fitted by OLS),nonlinear mixed-effect basic model and nonlinear mixed-effect generalized model.The goodness-of-fits and prediction accuracy of the four models were compared.For the mixed-effect model,four sampling strategies,i.e.,random sampling,large-DBH tree sampling,small-DBH tree sampling and medium-DBH tree sampling,were designed to calculate the random parameters.The effects of individual factor and stand level variables on the canopy-DBH relationship were simulated.Model evaluation indices included the determination coefficient (R2),mean absolute error (MAE) and root mean square error (RMSE).Results showed that the height to live crown base (HCB),relative spacing index (RS) and stand age (A) were the dominant factors in CW-DBH models.The goodness-of-fits of mixed-effect CW-DBH models (R2,MAE and RMSE) were 0.703 0,0.386 6 and 0.515 4,and those of mixed-effect generalized model were 0.705 1,0.382 2 and 0.513 6,respectively,which were better than those of the OLS models.However,the difference in goodness-of-fit between the mixed-effect basic and generalized models was not significant (below 1%).Canopy decreased with the increase of A and height of HCB,but increased with the increase of RS.

Key words: Pinus sylvestris var.mongolica, sand-fixing plantation, canopy-DBH, mixed-effect basic model, generalized model