Original scientific paper
Effects of heavy thinning on Turkey oak (Quercus cerris L.) tree and stand increment
M. Bobinac
S. Andrašev
Abstract
On permanent sample plots in middle-aged, artificially established, Turkey oak stand, the effects of heavy thinning (S.P.-1) and sanitation cutting (S.P.-2) were analysed on trees and stand increment, 5 and 10 years after cutting at the age of 46 years. Till the age of 56 years, 62% trees incremented on S.P.-1, and 95% trees on S.P.-2, compared to the initial state at the age of 46 years. Due to the devitalisation in the previous period, the remaining trees had the reduced capacity of growth reaction to the spatial increase and they compensated the increment loss slowly, which resulted due to the reduction of a great number of trees (38%) and volume (31%) on S.P.-1.
Five years after heavy thinning on S.P.-1 the compensated volume was 57.4 % compared to the state before thinning, and after 10 years, the volume increased by 10% compared to the state before thinning. Compared to the volume per ha on S.P.-2 at the age of 56 years, the volume on S.P.-1 was lower by 20.6%. However, total production on sample plots at the age of 56 years, regardless of the elimination of 38% trees on S.P.-1, was approximately identical, and the established rank was maintained (with minor differences) in the size of the total production between the sample plots before the heavy thinning.
Five years after heavy thinning on S.P.-1, current increment of basal area per ha was 89 %, and volume 88 %, compared to S.P.-2. In the following five-year period, current increment of basal area per ha of the same trees on S.P.-1 was 95%, and volume 92%, compared to S.P.-2. Throughout the study period, current increment of basal area and volume of the remaining trees per ha on S.P.-1 was 92% and 90%, compared to S.P.-2., as the consequence, primarily, of the different number of trees which incremented on sample plots. Current increment of diameter, basal area and volume per tree on S.P.-1. during the first five-year period was higher by 21-22%, during the second five-year period it was higher by 26-30%, and in the entire study period, it was higher by was 23-25%, compared to S.P.-2, and it is the consequence, primarily, of the different intensity of increment of the remaining trees on sample plots. In both five-year periods, the trees on S.P.-1 had greater diameter increment compared to the trees on S.P.-2 in all diameter degrees.
After 10 years, on S.P.-1, mean diameter of the remaining trees increased by 16.1%, basal area by 34.7%, and volume by 50.8%. During the same period on S.P.-2 mean diameter of the remaining trees increased by 13.2%, basal area by 28.4%, and volume by 40.4%, so it can be concluded that heavy thinning had a favourable effect on the increase of increment of the remaining trees during the study period.
Keywords
Q. cerris L.; permanent sample plots; heavy thinning; sanitation cutting; increment
Hrčak ID:
10304
URI
Publication date:
23.12.2006.
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