Variation and precision of assessment of tree taxation elements per diameter classes in beech high stands | Варијабилитет и прецизност процене таксационих елемената стабла по дебљинским класама у високим састојинама букве
2007
Копривица, М., Институт за шумарство, Београд (Serbia) | Матовић, Б., Институт за шумарство, Београд (Serbia)
The study results of the variation and the precision of assessment of the most significant taxation elements of beech tree per diameter classes are presented. Special attention was focused on the tree volume. The study data were collected in five beech high all-aged stands in East and West Serbia. The applied method was the systematic sample. The size of the sample was 1315 trees, i.e. from 152 to 310 trees per stands. The data were analysed by the method of descriptive statistics and the method of regression analysis. Models (1) and (2) define the dependence of standard deviation and variation coefficient on mean diameter in the diameter class, and model (3) defines the dependence of relative error of assessment on mean diameter in the diameter classes and the number of measured trees in the diameter class. The study results are several regression equations: for standard deviation of the tree basal area, volume and volume increment (4), (5) and (6), for variation coefficient of tree diameter, height, diameter increment, basal area, volume and volume increment (7)-(12), and for relative error of assessment of the above taxation elements (13)-(18). The study results can be practically implemented for the planning of the size and structure of the sample for the construction of beech volume tables. It was determined that the same number of trees should be selected in the sample for each diameter class, i.e. diameter degree, which depends on the required precision of the volume table. Total size of the sample should amount to 540 to 900 trees, i.e. per diameter degrees from 30 to 50 trees. In this case, it can be expected that the error of average tree volume in the first diameter class (10-20 cm) accounts for 14-13%, and in the last one (90-100 cm), for 2.0-1.5%.
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