摘要 【目的】构建包含竞争指标和气候因子的胸径生长模型,分析竞争和气候及其交互作用对杉木人工林胸径生长的影响,为气候变化背景下模拟抚育间伐、择伐后保留木的生长变化奠定基础,为森林适应性经营中科学合理地对杉木人工林进行间伐、择伐提供依据。【方法】基于江西省赣州市南康区、崇义县和上犹县杉木人工林固定样地数据,采用潜在生长量修正法构建胸径生长模型。利用分位数回归模拟潜在生长量,运用7个环境因子(5个气候因子:调查间隔期的平均温度、最高温度、最低温度、降水量和大于5℃的积温;2个地形因子:海拔和坡度)反映立地质量对潜在生长量的影响,依据参数显著性和方差膨胀因子确定可作为自变量的环境因子。采用指数函数形式构建修正函数,修正函数的竞争因子包括3个林分密度指标和3个单木竞争指标(2个与距离无关的竞争指标和1个与距离有关的竞争指标),筛选出最优竞争因子后考虑其与5个气候因子间的交互作用对估计精度的影响。通过模型评价,选出估计精度最高的模型添加样地水平随机效应参数,用于分析竞争和气候及其交互作用对杉木人工林胸径生长的影响。使用平均绝对误差(MAE)、平均相对误差绝对值(RMAE)和平均预估误差(MPE)评价模型估计精度。【结果】海拔、调查间隔期的最低温度和降水量对杉木人工林胸径潜在生长量具有显著影响。胸径20 cm时,潜在生长量达到最大值,调查间隔期的最低温度和降水量对潜在生长量最大值呈正向影响,而海拔则呈负向影响。对比各竞争指标构建的胸径生长模型估计精度发现,含与距离无关的竞争指标的生长模型估计精度最高,其次是含与距离有关的竞争指标的生长模型。鉴于气候和竞争的交互作用可提升模型估计精度,对比只在修正函数中考虑竞争因子的模型,考虑交互作� 【Objective】This study aimed to construct a growth model of diameter at breast height(DBH)for Chinese fir plantations based on competition and climate factors,and analyze effects of competition,climate factors and their interactions on DBH growth.The results were expected to provide a reference for the growth of reserved trees after thinning and selective cutting under climatic changes.【Method】based on the permanent sample plots in the south of Jiangxi Province,the potential increment equation with multiplicative modifiers was used to construct DBH growth model.The quantile regression technique was used to model the potential DBH increment,and seven environmental factors(mean temperature,maximum temperature,minimum temperature,precipitation,accumulated temperature greater than 5℃,elevation,slope)were used to describe the effects of site quality on potential increment.Parameter significance and variance inflation factor were chosen to determine environmental factors,which could be the independent variables.Exponential function form was used to construct modifier functions.Competition variables included in the modifier functions were three stand-level and three tree-level competition indices(2 distance-independent indices and 1 distance-dependent index).The interactions between the selected best competition index and five climate factors on good-of-fit of growth models were also considered.According to model evaluation,the model with the best good-of-fit was selected to add plot-level random effect parameters,and then used to analyze the effects of competition,climate and their interactions on DBH growth of Chinese fir plantations.Model evaluation criteria included mean absolute error(MAE),relative mean absolute error(RMAE),and mean predicted error(MPE).【Result】Elevation,minimum temperature and precipitation during investigation intervals showed significant effects on the potential DBH increment for Chinese fir.The potential increment would reach the maximum when DBH was 20 cm.Minimum temperature and p
出处 《林业科学》 EI CAS CSCD 北大核心 2021年第3期39-50,共12页 Scientia Silvae Sinicae
基金 国家自然科学基金项目“气候和竞争对亚热带杉木人工林单木生长的交互作用”(31700563) 江西省教育厅科技计划项目“气候敏感的杉木人工林林分断面积生长模型研究”(GJJ160397)。
