DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 1-2/2018 str. 38 <-- 38 --> PDF |
For the reconstruction of the growth of dominant trees in height and diameter in the study culture, two dominant trees at the age of 40 were analyzed. The trees belonged to D100 and D400 category of dominant trees and the model of height growth was developed. The height growth model was constructed using the Chapman-Richards function (Pienaar and Turnbull, 1973). The model of dominant tree height growth was in line with the increase in the mean stand height of dominant trees in the period between the ages of 41 and 50 taken from the height curve. To define the effects of thinning on the growth of trees, we compared the current diameter (idt) and height (iht) increments obtained by a detailed analysis of dominant trees (D100 and D400) in the periods between the age of 25 and 32 and between the age of 33 and 40. At the stand level, we compared the current diameter (idt) and height (iht) increments of dominant trees (D100 and D400) in the periods between the age of 33 and 40 and between the age of 41 and 50. We further compared the current diameter, basal area, and volume increments of all trees and of aspirant trees in the periods between the age of 33 and 40 and 41 and 50. Statistical data analysis comprised measurement of standard numerical parameters of diameter structure: arithmetic mean (da), standard deviation (sd), coefficient of variation (Cv), variation width (vw), minimum (dmin), maximum (dmax), coefficient of skewness (α3) and kurtosis (α4). The Kolmogorov-Smirnov nonparametric test (|D| statistics) was used for the mutual comparison of the structures of the slenderness degree (h/d1,3 ratio). The t-test was used to test the differences between the current increments in different periods. Research results Rezultati istraživanja Stand structure elements – Elementi strukture sastojine The most important data about the elements of stand structure at the ages of 32, 40 and 50 are shown in Tables 1 and 2. At the age of 32, there were 3,911 trees per hectare, with a basal area of 57.39 m2·ha-1 and the volume of 384,17 m3·ha-1, while the average periodic increment at the age of 32 amounted to 12 m3·ha-1·year-1. Trees were distributed in diameter degrees from 7.5 to 22.5 cm, with the maximum distribution in the diameter degree of 12.5 cm (Graph 1). The quadratic mean diameter was 13.7 cm, Lorey`s mean |