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林业科学 ›› 2020, Vol. 56 ›› Issue (9): 184-192.doi: 10.11707/j.1001-7488.20200920

• 研究简报 • 上一篇    下一篇

基于林层划分的湖南栎类天然次生林断面积生长模型

胡松1,朱光玉1,3,*,陈振雄2,卢侃1,黄朗1,刘卓1   

  1. 1. 中南林业科技大学林学院 长沙 410004
    2. 国家林业和草原局中南林业调查规划设计院 长沙 410014
    3. 南方森林资源经营与监测国家林业局重点实验室 长沙 410004
  • 收稿日期:2018-06-07 出版日期:2020-09-25 发布日期:2020-10-15
  • 通讯作者: 朱光玉
  • 基金资助:
    国家自然科学基金项目(31570631);国家林业局项目(1692016-06);湖南省教育厅重点项目(16A224);湖南省自然科学基金面上项目(2017JJ2405);中南林业科技大学研究生科技创新项目(CX20201002)

Basal Area Growth Model for Oaks Natural Secondary Forest in Hunan Province Based on Storey Identification

Song Hu1,Guangyu Zhu1,3,*,Zhenxiong Chen2,Kan Lu1,Lang Huang1,Zhuo Liu1   

  1. 1. Forestry College, Central South University of Forest&Technology Changsha 410004
    2. Central South Forest Inventory and Planning Institute of National Forestry and Grassland Administration Changsha 410014
    3. Key Laboratory of State Forestry Administration on Forest Resources Management and Monitoring in Southern Area Changsha 410004
  • Received:2018-06-07 Online:2020-09-25 Published:2020-10-15
  • Contact: Guangyu Zhu

摘要:

目的: 研究复层林林分层次对湖南栎类天然次生林断面积生长的影响,从林层角度构建复层混交异龄林断面积生长模型,反映不同林层的断面积生长规律,为湖南栎类天然次生林的林分生长收获和经营管理提供参考。方法: 以湖南省51块栎类天然次生林样地为研究对象,采用全树高聚类法、国际林联标准和光竞争高度法划分林层,以Schumacher式分别对全林分及上层林、下层林断面积进行拟合,选择最优林层划分方法;考虑总断面积与各林层断面积的相容性问题,通过比例平差法构建相容性林层断面积生长模型。结果: 全树高聚类法、国际林联标准和光竞争高度法的林层划分结果均满足《森林资源规划设计调查技术规程》要求,且不同林层间统计量的F检验结果均显著;Schumacher式能较好模拟全林分及不同林层的断面积生长,其确定系数(R2)均在0.92以上,相比不分层的全林分断面积生长模型,分层后不同林层断面积生长模型R2从0.925 9提高到0.945 5~0.984 6;选择国际林联标准的优势高划分作为栎类天然次生林最优林层划分方法,其断面积生长模型精度最高(R2=0.970 4,MAE=1.458 8,RMSE=2.178 6),与不分层的全林分断面积生长模型相比,R2提高5.0%,平均绝对误差(MAE)、均方根误差(RMSE)分别降低39.8%、26.4%;以总断面积为基础控制的比例平差法能较好解决总断面积与各林层断面积的相容性问题,相比各分项的独立预估模型,上层林R2由0.974 6提高到0.986 8,下层林R2由0.980 2提高到0.988 8。结论: 复层林林分层次对湖南栎类天然次生林断面积生长影响显著,考虑林层效应对研究林层断面积特征、提高断面积建模精度具有重要作用。从林层角度揭示亚热带栎类天然次生林林分断面积生长过程,对栎类天然次生林的林分生长收获和经营管理具有重要意义。

关键词: 林层划分, 断面积生长模型, 比例平差法, 相容性, 栎类

Abstract:

Objective: This paper was implemented to study the effects of forest storey of multi-storied stand on Oaks natural forest basal area growth model in Hunan Province. It would reflect the basal area growth rules of different storeys by building basal area growth models from the perspective of forest storey in order to provide references for the growth harvesting and management of the Oaks natural secondary forest in Hunan Province. Method: After the storey identification by using whole tree height clustering,IUFRO standard and TRSRAT,the model of Schumacher was used to fit the basal area of whole stand,upper layer and lower layer based on the 51 plots of Oaks natural secondary forest in Hunan Province,and the optimal method of storey identification was selected. Considering the compatibility of the total basal area and each forest layer basal area,the compatible storey basal area growth model was built by adjustment in proportion. Result: The results of storey identification by whole tree height clustering,IUFRO standard and TRSRAT were all satisfied with the requirements of technical regulations for forest resources planning and design investigation,and the F testing of different forest layer statistics were significant. The model of Schumacher could better simulate the growth of whole stand and different forest layers,the coefficients of determination (R2) were all above 0.92. Compared with the whole stand basal area growth model without storey identification,the coefficient of determination (R2) of different forest layers with storey identification was increased from 0.925 9 to 0.945 5-0.984 6.The IUFRO standard was selected as the optimal method of storey identification,and the accuracy of the basal area growth model was the highest (R2=0.970 4,MAE=1.458 8,RMSE=2.178 6).Compared with the whole stand basal area growth model without storey identification,the determination coefficient (R2) was increased by 5.0%,the mean absolute error (MAE) and the root mean square error (RMSE) was respectively decreased by 39.8% and 26.4%. The proportional adjustment method based on total basal area could better solve the problem of the compatibility between total basal area and each forest layer basal area. Compared with the independent prediction model of each forest layer,the determination coefficient (R2) of upper layer was increased from 0.974 6 to 0.986 8,and the determination coefficient (R2) of lower layer was increased from 0.980 2 to 0.988 8. Conclusion: The effects of forest storey of multi-storied stand on Oaks natural forest basal area growth model in Hunan Province was significant. It was important to study the characteristics of different forest storeys and improve the modeling accuracy by considering storey effection. The research results were expected to reveal the growth process of forest basal area in subtropical Oaks forest,which was of great significance to growth harvesting and management of the Oaks natural secondary forest.

Key words: storey identification, basal area growth model, adjustment in proportion, compatible, Oaks

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