DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 9-10/2020 str. 23     <-- 23 -->        PDF

the Loray’s mean height (hL) and the top height based on 20% thickest trees (Hdom) were calculated. The standing volume of the plantation was calculated using volume tables for black alder (Mirković 1975) with the analytical shape:
                 [m3]       [1]
                 [m3]       [2]
The height curves were fitted using the function of Chapman-Richards. Power function was used to fit the relation between h/DBH ratio and corresponding diameters at breast height. Linear function was used to fit the relation between the trees’ PAI of growth characteristics and their initial values (at age 11 years).
RESULTS
REZULTATI
Growth of the trees and the linear plantation – Rast stabala i zasada
High values of mean diameters and heights were recorded in Italian alder linear plantation (Table 1). On the basis of the calculation that there are 200 trees per hectare, the basal area was close to 10 m2∙ha−1 at age 11 years and volume was slightly over 100 m3∙ha−1. At age 16 years, basal area was close to 35 m2∙ha−1 and volume slightly over 300 m3∙ha−1.
The diameter distributions are unimodal in both measurements. Most of the trees are in the diameter class 22.5 cm (age 11 years) and 47.5 cm (age 16 years) — Figure 1. DBH arithmetic mean is in the modal diameter class in both of the measurements. The DBHs at age 11 years were within the range of 13–35 cm with the coefficient of variation of 23%. At age of 16 years, the DBHs were within the range of 25–64 cm with the coefficient of variation reduced by 1.4% since the age of 11 years while the standard deviation increased by twofold.
In both of the measurements, the diameter distributions were characterised by weak left skewness and platykurtic shape (Table 2).
The height range was between 10.3 and 16.2 m at age 11 years and 14.5 and 22.9 m at age 16 years. As trees age, the standard deviation of the height distribution slowly increases while coefficient of variation decreases. The distribution shape changes with age as well. At age 11 years, the distribution shape is skewed to the right and platykurtic