南京林业大学学报(自然科学版) ›› 2023, Vol. 47 ›› Issue (2): 130-140.doi: 10.12302/j.issn.1000-2006.202204037

• 研究论文 • 上一篇    下一篇

基于TLS辅助的长白落叶松一级枝条生物量模型构建

唐依人1(), 贾炜玮1,2,*(), 王帆1, 孙毓蔓1, 张颖1   

  1. 1.东北林业大学林学院,黑龙江 哈尔滨 150040
    2.东北林业大学森林生态系统可持续经营教育部重点实验室,黑龙江 哈尔滨 150040
  • 收稿日期:2022-04-15 修回日期:2022-06-13 出版日期:2023-03-30 发布日期:2023-03-28
  • 通讯作者: * 贾炜玮(jiaww2002@163.com),教授。
  • 基金资助:
    国家自然科学基金区域联合基金项目(U21A20244)

Constructing a biomass model of Larix olgensis primary branches based on TLS

TANG Yiren1(), JIA Weiwei1,2,*(), WANG Fan1, SUN Yuman1, ZHANG Ying1   

  1. 1. School of Forestry, Northeast Forestry University, Harbin 150040, China
    2. Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Northeast Forestry University, Harbin 150040, China
  • Received:2022-04-15 Revised:2022-06-13 Online:2023-03-30 Published:2023-03-28

摘要:

【目的】探究利用地基激光雷达(terrestrial laser scanning,TLS)点云数据估测枝条生物量的可行性,构建预测长白落叶松(黄花落叶松)枝条生物量的最优模型。【方法】以利用孟家岗林场26株长白落叶松点云数据提取出的733个一级枝条的特征因子[枝长(LBL)、弦长(LBCL)、基径(dB)、着枝角度(AB)、弓高(HBAH)、枝条基部断面积(SBAB)、相对着枝深度(dRDINC)]和对应的实测数据为数据源,分别建立枝条水平上的一级枝条生物量基础模型,通过对比基础模型之间的差异来分析利用TLS数据建立枝条生物量模型的可行性。最后利用TLS数据分别对比基础模型、混合效应模型和随机森林模型的预测效果。【结果】基础模型中最终选定的自变量为SBABLBCL。利用TLS数据建立的枝条生物量基础模型具有更好的预测精度。对比3种模型预测能力结果显示,随机森林模型无论在训练集还是测试集上都表现出最好的效果,具体顺序为:随机森林模型>混合效应模型>基础模型。其中随机森林模型的决定系数(R2)相较于混合模型和基础模型分别提高了1.32%和4.89%,均方根误差(RMSE)分别降低了11.23%和13.60%。【结论】基于TLS利用随机森林算法能够准确对枝条生物量进行估测,不仅为随机森林算法在林分生长模型上的应用奠定了一定的实践基础,也为TLS在树冠结构研究中的应用提供了重要的参考价值。

关键词: 长白落叶松(黄花落叶松), 点云数据, 枝条特征因子, 枝条生物量, 混合模型, 随机森林

Abstract:

【Objective】 To explore the feasibility of using terrestrial laser scanning (TLS) point cloud data to estimate branch biomass and find the optimum model to predict the branch biomass of Larix olgensis. 【Method】 The characteristic factors (branch length (LBL), branch chord length (LBCL), branch diameter (dB), branch angle (AB), branch arch height (HBAH), basal area of branches (SBAB), and relative depth within the crown (dRDINC)) of 733 first-order branches extracted using point cloud data of 26 artificial larch plants and the corresponding measured data from Mengjiagang Forestry Farm were used as data sources to establish first-level branch biomass base models at the branch level. Additionally, the feasibility of using TLS data to establish branch biomass models by comparing the differences between base models were analyzed. Finally, the prediction effects of the base model, mixed-effects model, and random forest model were compared separately using TLS data. 【Result】 The independent variables selected in the base model were SBAB and LBCL. Using TLS data to build the branch biomass base model had a better prediction accuracy. Comparing the results of the three models showed that the random forest model showed the best results both on the training and test sets, in the following order: random forest model > mixed-effects model > base model. The R2 of the random forest model improved by 1.32% and 4.89%, and the RMSE decreased by 11.23% and 13.60%, respectively, compared to the mixed model and the base model. 【Conclusion】 The results of this paper proved that the branch biomass can be estimated accurately based on TLS using the random forest algorithm, which not only laid a practical foundation for the application of the random forest algorithm on stand growth models, but also provided an important reference value for the application of TLS in the study of crown structure.

Key words: Larix olgensis, point cloud data, branch characterization factor, branch biomass, mixed-effects model, random forest

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