Generalized model of pine trees diameter distribution

A generalized statistical model for the distribution of tree diameters for pine forest plantations, developed on the basis of a three-parameter Weibull function, is presented. Its parameters were restored using data from 231 distribution series on 24 permanent sample plots in the Forest Experimental Station of the Russian State Agrarian University — Moscow Timiryazev Agricultural Academy from the first and second central moments of the distribution. It is shown that their estimates can be obtained from the equations of connection with the root-mean-square diameter of trunks in a forest stand. It was revealed that the developed model approximates with high accuracy the actual distributions of tree diameters in maturing, middle-aged and mature forest stands, and in young stands there may be deviations between the actual and predicted frequency values. It is shown that the main purpose of the developed model is to predict the distribution of diameters of tree trunks in future ages of forest stands to optimize the management of forest plantations.