Verification of three-parameter models of dependence of height on the diameter at breast height for birch stands of the European part of Russia

• Main Authors: A. V. Lebedev, V. V. Kuzmichev
• Format: Article
• Language: English
• Published: Russian Academy of Sciences, Siberian Branch Publishing House 2020-10-01
• Series: Сибирский лесной журнал
• Subjects: birch; three-parameter model; selection of models
• Online Access: https://xn--80abmehbaibgnewcmzjeef0c.xn--p1ai/upload/iblock/7fc/7fc5a3eb99f96e21986ea1c8f181bc92.pdf

Of great importance when conducting forestry operations and scientific research is the accuracy of determining the height of trees. The height of trees in a particular area is usually calculated using models, where it is a function of diameter at breast height. Among simple models, three-parameter models are the most flexible and allow for more detailed transmission of the dependence. The purpose of the work is to select the most adequate one from the set of three-parameter models based on the materials used to measure model trees in birch stands, which conveys the relationship between the height of trees and diameter at breast height. On the materials of 23 sample plots with the measurement of model trees laid in birch stands of the Forest Experimental District of the Timiryazev Agricultural Academy, parameters were determined for 11 three-parameter models selected from literary sources. Model parameters were calculated by minimizing the standard error. The quality of the models was evaluated by the following metrics: the square root of the standard error, the coefficient of determination, the Akaike information criterion, the Bayes information criterion. The obtained results confirmed the advisability of using in practice the Mitcherlich equation (also known as Drakin–Vuyevsky, Chapman–Richards), which among the three-parameter models shows the best quality. The results of data analysis show that, from a statistical point of view, the differences obtained in the quality of models are not significant at the 5 % level (t-test). Mitcherlich’s equation can be used in practice when carrying out forestry and research work in birch stands growing in the central regions of the European part of Russia. The methodology of the study allows you to repeat the same work for tree species and forest conditions, for which information about the nature of the relationship of height with the diameter at breast height is incomplete or absent.