摘要
[目的]建立包含林分竞争和气候的不同初植密度杂种落叶松单木断面积生长模型,为未来气候变化下杂种落叶松人工林经营提供理论依据。[方法]基于2004—2023年黑龙江江山娇实验林场杂种落叶松人工林16块样地的23 399个断面积观测数据,选取4种常用的理论生长模型,构建包括树龄、竞争和气候的不同初植密度林分的单木断面积基础哑变量模型,在此基础上引入样木水平随机效应构建单木断面积混合效应模型。基于混合效应模型的固定效应参数模拟杂种落叶松单木断面积对树龄、竞争、气候和初植密度的响应关系。[结果]与基础模型相比,引入树龄、林分竞争和气候因子的不同初植密度单木断面积哑变量模型的Ra2由0.525提升到0.554,RMSE由52.3 cm^(2)降低到50.7 cm^(2)。与哑变量模型相比,样木水平随机效应的引入使模型拟合精度得到极大提高(Ra2=0.978,RMSE=13.1 cm^(2)),并改善了异方差的问题。不同初植密度下的单木断面积呈现显著差异,为3 300株·hm^(−2)>2 500株·hm^(−2)>4 400株·hm^(−2)>6 600株·hm^(−2)。相同初植密度下,单木断面积随树龄和最冷月平均温度的增大而增大,随林分密度的增大而减小。[结论]树龄、林分竞争和气候因子是影响杂种落叶松单木断面积生长的重要因子,其中树龄是影响最大的因子,林分竞争次之。不同初植密度林分杂种落叶松人工林单木断面积存在差异,综合来看,初植密度为3 300株·hm^(−2)林分生长趋势较好。
[Objective]This study aimed to develop an individual-tree basal area growth model for Hybrid larch plantations,incorporating stand competition and climatic factors under different initial planting densities.The model provides a theoretical basis for the management of these plantations under future climate change.[Method]Based on 23399 basal area observations collected from 2004 to 2023 across 16 plots of hybrid larch plantations in Jiangshanjiao Farm,Heilongjiang Province,four commonly used theoretical growth models were evaluated.Dummy-variable models of individual tree basal area for stands with different initial planting densities that included age,competition,and climate as predictor variables were developed.On this basis,a mixed-effects model was developed introducing random effects at the tree level.The fixed-effect parameters of the final model were used to simulate the responses of tree basal area growth to tree age,competition,climate,and planting density.[Result]Compared with the basic model,incorporating tree age,stand competition,and climatic factors into the dummy variable model for different planting densities improved the model fit,with the adjusted R2 increasing from 0.525 to 0.554 and RMSE decreasing from 52.3 cm^(2) to 50.7 cm^(2).Compared to the dummy variable model,the random effects model improved model fitting accuracy(Ra 2=0.971,RMSE=13.1 cm^(2)).It was found that the basal area of individual trees at different initial planting densities showed a significant difference,with the trend of initial planting densities of 3300 plants·hm^(−2)>2500 plants·hm^(−2)>4400 plants·hm^(−2)>6600 plants·hm^(−2).Under the same initial planting density,individual tree basal area increased with age and MCMT and decreased with increasing N.[Conclusion]Tree age,stand competition and climate factors are important factors affecting tree basal area growth in Hybrid Larch plantations,with age being the most important factor.Significant differences exist in individual-tree basal area across different initial planting densities,with the 3300 trees·hm^(−2)density exhibiting superior growth performance overall.
作者
朱万才
刘奇峰
潘研
刘兆刚
ZHU Wan-cai;LIU Qi-feng;PAN Yan;LIU Zhao-gang(College of Forestry,Northeast Forestry University,Harbin 150040,Heilongjiang,China;Heilongjiang Forestry Science Research Institute,Harbin 150081,Heilongjiang,China)
出处
《林业科学研究》
北大核心
2025年第6期80-88,共9页
Forest Research
基金
黑龙江省省属科研院所科研业务费项目(QN2024-06)。
