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<p>Crown volume (CV) and crown surface area (CSA), important indicators of tree vigor, are rarely used in forest management at present because they cannot be directly measured. Therefore, developing static and dynamic CV and CSA models based on easily measured variables is essential at present. The present study developed static and dynamic CV and CSA models for <i>Larix kaempferi</i> plantations with large latitudinal ranges. Data from 228 individual trees from 76 plots in Hubei Province (approximately 30°N), Gansu Province (approximately 33°N) and Liaoning Province (approximately 42°N) were utilized for model development. The final CV and CSA models used the same tree variables, including diameter at breast height (DBH), crown width, and crown length, and the interaction between mean annual temperature (MAT) and DBH. Nonlinear mixed effect models at the plot level were developed for the CV and CSA models. The findings indicated that the optimal models could explain 92.7% and 95.7% of the variances in CSA and CV, respectively, with no significant residual heterogeneity. CSA and CV growth models of <i>Larix kaempferi</i> were also developed by constructing a height to crown base model combined with branch growth and tree height growth. The variables included in the final CSA and CV growth models were tree age (AGE), CL, and February precipitation as snow (PAS_02), with the nonlinear mixed effect models including random effects at the tree level. The results suggested that the growth models explained 84.3% and 84.6% of the variation in the dynamics of the CSA and CV, respectively. The CSA and CV first followed a pattern of a rapid initial increase and a subsequent steady decrease. The models developed in this study are physiologically justifiable and statistically robust. CSA and CV models can provide a scientific approach for forecasting CSA and CV and lay the foundation for formulating reasonable management measures for <i>Larix kaempferi</i> planted in China.</p>

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A comprehensive static and dynamic crown volume and crown surface area model for planted Larix kaempferi from different climate regions in China

  • 期刊论文

  • 发表日期：

    2025年8月7日

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  • Yixi Zou,
  • Huilin Gao,
  • Jiateng Liu,
  • Yiwen Tong

摘要

Crown volume (CV) and crown surface area (CSA), important indicators of tree vigor, are rarely used in forest management at present because they cannot be directly measured. Therefore, developing static and dynamic CV and CSA models based on easily measured variables is essential at present. The present study developed static and dynamic CV and CSA models for Larix kaempferi plantations with large latitudinal ranges. Data from 228 individual trees from 76 plots in Hubei Province (approximately 30°N), Gansu Province (approximately 33°N) and Liaoning Province (approximately 42°N) were utilized for model development. The final CV and CSA models used the same tree variables, including diameter at breast height (DBH), crown width, and crown length, and the interaction between mean annual temperature (MAT) and DBH. Nonlinear mixed effect models at the plot level were developed for the CV and CSA models. The findings indicated that the optimal models could explain 92.7% and 95.7% of the variances in CSA and CV, respectively, with no significant residual heterogeneity. CSA and CV growth models of Larix kaempferi were also developed by constructing a height to crown base model combined with branch growth and tree height growth. The variables included in the final CSA and CV growth models were tree age (AGE), CL, and February precipitation as snow (PAS_02), with the nonlinear mixed effect models including random effects at the tree level. The results suggested that the growth models explained 84.3% and 84.6% of the variation in the dynamics of the CSA and CV, respectively. The CSA and CV first followed a pattern of a rapid initial increase and a subsequent steady decrease. The models developed in this study are physiologically justifiable and statistically robust. CSA and CV models can provide a scientific approach for forecasting CSA and CV and lay the foundation for formulating reasonable management measures for Larix kaempferi planted in China.