In the course of the performed investigations, 4 indices of the volume increment were subjected to basic analysis concerning the main statistical characteristics. The empirical material comprised 94 pine trees derived from an 86-year old pine stand. A complete bole analysis was carried out on cut trees and then, in consecutive 5-year increment periods, 4 indices of the volume increment: C₁, C₂, C₃, C₄ and volume increment intensity as i’. Set against the variability of the volume increment intensity i’, the variability coefficients in the consecutive 5-year increment periods of the volume increment index C₁ were bigger, C₃ and C₄ – comparable and C₂ – smaller than the variability coefficients i’. There was no correlation between the mean of two volume increment indices (C₂ and C₃) and the age of trees. The mean of the C₁ index increased with the age of trees. The C₄ mean declined with the increase of tree age. The population of the volume increment intensity i’ in each increment period was characterised by the distribution which did not differ from the normal distribution. The C₃ index distribution differs for the normal distribution for 1 increment period, of the C₄ – for 2, C₂ – for 6 and of the C₁ – for 12 out of the 15 analysed periods.

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