DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 3-4/2023 str. 14     <-- 14 -->        PDF

density (sd) were examined for standing trees. The following regression models were used to model these relationships. Statistical information on the regression equations were given in Table 2.
Ln = –0.8375 – + 0.6141 ln t · SI +
                 – 0.003635sd2   (5)
Ln = –6.3186 + 1.3570 ln t · SI – 0.0003 t · SI +
                 –          (6)
Ln = –3.2944 + 0.11848 ln SI · sd +
                0.6504 ln t · SI · sd               (7)
Ln = 10.5271 + 0.00001632 t2 – 1.1718 ln t –
                0.0008041SI2 + 0.0145sd2 (8)
Ln = –3.4113 + 1.1039 ln t – 0.00001816 t2 +
                0.9174 ln sd + 0.9145 ln SI (9)
These equations are subject to systematic error because they are logarithmic (Akalp, 1978). Therefore, the values obtained from the equations must be multiplied by the correction factor (f) of natural logarithm (ln) to correct this systematic error (Baskerville, 1972).
                Correction factor = Cf =     (10)
Where e represents the natural logarithm (2.718281828) and Sy.x represents the standard error of the equation in these equations.
Standing timber and removed tree elements in the yield tables were determined as a function of stand age, site index and stand density using the equations given in Eq. 5-9 and density-dependent Calabrian pine yield tables were constructed. The other elements of the yield table were also predicted by these equations. The standing timber and removed trees elements and the other elements of the yield table were calculated separately for 5-year age intervals (between 10 and 140), 5 degrees of stand density (for 2.0 – 4.0 - 6.0 – 8.0 -10.0), and 3 classes of SI (I-II-III). In addition, our relative density values ranges from 0.3 to 12.4.