【目的】通过在削度方程中引入竞争指标，构建含有竞争变量的削度方程，探究竞争对长白落叶松（Larix olgensis）干形的影响，为长白落叶松人工林经营提供理论依据。【方法】以吉林省东丰县林业局长白落叶松人工林为研究对象，以修正Kozak（2004）削度方程为基础模型，将样地作为分类变量，拟合不同组合的混合参数，利用赤池信息准则（AIC）、贝叶斯信息准则（BIC）及对数似然值（Loglik）对模型拟合优度进行评价，并对不同模型进行似然比检验，确定最优样地水平的混合参数。在此基础上，将最优混合参数替换为包含竞争指标的线性函数，构建广义削度方程。利用广义削度方程模拟树木在不同竞争强度下的干形变化。【结果】①当仅考虑1个混合参数时，模型拟合精度最高，增加混合参数的数量并未显著提高模型拟合优度。②通过逐步添加变量得到的最优竞争指标组合为I_c5（Hegyi竞争指数）、I_c6（大小比数）、I_c7（竞争木平均胸径）及I_c8（竞争木平均距离），其中Hegyi竞争指数对干形影响最为显著。③构建的广义削度方程拟合精度优于基础模型。④干形曲线模拟结果表明，竞争显著影响长白落叶松的干形。随着竞争强度增加，落叶松削度逐渐增大，且大径阶林木的干形对于竞争强度的变化表现出更高的敏感性。【结论】在长白落叶松人工林经营过程中，尤其是在以培育大径材为目标的林分中，应及时对目标树竞争范围内的林木进行择伐，以调控竞争关系，减轻目标树所受竞争压力，进而促进其生长。

【Objective】This study investigates the effects of competition on the stem taper of Larix olgensis by incorporating competition indices into a taper equation，thereby developing a competition-inclusive taper model to provide a theoretical foundation for the silvicultural management of L. olgensis plantations.【Method】Data were collected from L. olgensis plantations in Dongfeng County，Jilin Province，China. The modified Kozak（2004）variable-exponent taper equation served as the base model. Plots were treated as grouping variables，and nonlinear mixed-effects models with various parameter combinations were fitted. Model performance was assessed using Akaike’s Information Criterion（AIC），Bayesian Information Criterion（BIC），and log-likelihood values. Likelihood ratio tests were applied to compare models and identify the optimal plot-level mixed-effects parameters. These optimal parameters were subsequently expressed as linear functions of competition indices to formulate a generalized taper equation incorporating competition effects. The generalized taper equation was used to simulate stem profile variations under differing competition intensities.【Result】（1）Models with a single mixed-effects parameter exhibited the highest fitting precision； adding further mixed parameters did not substantially enhance model accuracy.（2）Stepwise variable selection identified the optimal competition indices as I_c5（Hegyi competition index），I_c6（neighborhood comparison），I_c7（average diameter of competing trees），and I_c8（average distance of competing trees），with the Hegyi competition index exerting the strongest influence on stem taper.（3）The generalized taper equation outperformed the base model in terms of fitting accuracy.（4）Simulations of stem profiles revealed that competition significantly influences the stem form of L. olgensis. As competition intensity increased，stem taper progressively increased，with large-diameter trees demonstrating greater sensitivity to competition variations.【Conclusion】In the management of L. olgensis plantations，particularly for stands oriented toward large-diameter timber production，selective cutting should be conducted timely to remove competing trees within the competitive neighborhood of target trees. This silvicultural intervention can effectively regulate inter-tree competition dynamics，alleviate the competitive stress exerted on target trees，and consequently facilitate their growth and development.