Generic crown length models of two-needled pines

The morphology of tree crowns determines the scale and effectiveness of physiological processes, in particular, of photosynthesis, respiration and transpiration, which determine the growth and development of a tree, as well as the quality of wood. Therefore, researchers are focusing on developing models of such morphological characteristics as crown length, relative crown length, and height to crown base. The morphological characteristics of the crown serve as predictive variables in models of crown diameter, vertical profile, tree biomass, and crown fires. The purpose of this study is to build generic models for estimating crown length, relative crown length (crown ratio) and height to crown base based on easily measurable dendrometric characteristics of the tree based on the materials of the author's database for two–needled pines (subgenus Pinus L.) of Eurasia. To achieve this goal, 2,700 model trees with measured taxation indicators were selected from the author's database. Since the study has a continental level, the analysis was performed at the level of a subgenus of two–needled pines as a set of vicarious species, bearing in mind that no species grows throughout Eurasia. As a result, generic multiple models were built to evaluate the morphological parameters of the crown – crown length, crown ratio and height to crown base – by stem diameter at breast height, height and age of the tree, explaining from 52 to 88 % of the variability of a particular morphological index of the crown, and their regression coefficients for independent variables are significant at the probability level p < 0.001 and higher. The proposed multiple models for estimating the morphological parameters of the crown based on the known dendrometric characteristics of the tree can be used in dynamic models of tree and stand growth, in the development of biomass models of trees and stands, as well as in the modeling of crown fires. 

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