Forests 2014, 5(11), 2825-2845; doi:10.3390/f5112825
Quantifying the Variability of Internode Allometry within and between Trees for Pinus tabulaeformis Carr. Using a Multilevel Nonlinear Mixed-Effect Model
1
Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China
2
East China Forest Inventory and Planning Institute, State Forestry Administration, Hangzhou 310019, China
*
Author to whom correspondence should be addressed.
Received: 17 June 2014 / Revised: 10 November 2014 / Accepted: 11 November 2014 / Published: 21 November 2014
Abstract
Allometric models of internodes are an important component of Functional-Structural Plant Models (FSPMs), which represent the shape of internodes in tree architecture and help our understanding of resource allocation in organisms. Constant allometry is always assumed in these models. In this paper, multilevel nonlinear mixed-effect models were used to characterize the variability of internode allometry, describing the relationship between the last internode length and biomass of Pinus tabulaeformis Carr. trees within the GreenLab framework. We demonstrated that there is significant variability in allometric relationships at the tree and different-order branch levels, and the variability decreases among levels from trees to first-order branches and, subsequently, to second-order branches. The variability was partially explained by the random effects of site characteristics, stand age, density, and topological position of the internode. Tree- and branch-level-specific allometric models are recommended because they produce unbiased and accurate internode length estimates. The model and method developed in this study are useful for understanding and describing the structure and functioning of trees. View Full-TextKeywords:
internode allometry; mixed-effect models; Pinus tabulaeformis Carr.; variance of random effects
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Diao, J.; Lei, X.; Wang, J.; Lu, J.; Guo, H.; Fu, L.; Shen, C.; Ma, W.; Shen, J. Quantifying the Variability of Internode Allometry within and between Trees for Pinus tabulaeformis Carr. Using a Multilevel Nonlinear Mixed-Effect Model. Forests 2014, 5, 2825-2845.