prilagođeno pretraživanje po punom tekstu

ŠUMARSKI LIST 3-4/2023 str. 17     <-- 17 -->        PDF

observed that in the age groups where MAI was highest, its value was equal to CAI. Consequently, the optimal management period (the optimal rotation period) that would lead to the highest yields for pure Calabrian pine stands in Antalya and Mersin can be set at 60, 65 and 75 years for the SI classes of I, II and III, respectively. Site productivity described by maximum MAI, was 10.39 at 60 years, 7.42 at 65 years and 4.39 m3/ha at 70 years per year for good, medium and poor sites, respectively (Figure 6).
Total stand volume for Calabrian pine for a given age generally increases steadily with decreasing rates as they get older with improving site quality or increasing density. The mean annual volume increment of stand for Calabrian pines for a given age increases irregularly for different site quality classes and stand density levels (Table 3).
The results of the density-dependent yield tables generated in this study for the Calabrian pine were compared with the previous yield tables generated by Shater et al. (2011) in Syria, de-Miguel et al. (2010) in Syria and Lebanon, Çatal (2009) in Turkey, Palahí et al. (2008) in northeastern Greece, Erkan (1995) and Alemdağ (1962) in Turkey, and with the density-dependent yield table developed by Yeşil (1992) in Turkey. The results were similar and consistent with the growth rules associated with the stand models. The reciprocal equivalents of the variables were considered in the comparisons. For example, the values of the table for the normal stand density level of 8 in this study were compared with the values of the table given by Yeşil (1992) for the normal stand density level. Similarly, yield table values for stands of tree species with optimal growing conditions (i.e., SI class I) were compared for consistency (Akalp, 1978; Kahriman et al., 2016a). Comparisons of the number of trees, total stand volume, current and mean annual volume increment of Calabrian pine stands in high SI class and at normal density with previous studies are shown in Figures 7 and 8.
In study of Palahí et al. (2008), the number of trees was consistently higher between 40 and 100 years. With the exception of Alemdağ (1962) up to the age of 50 and Palahí et al. (2008) between 40 and 100 years, the number of trees in Calabrian pine stands reported in the yield tables of this study was higher than in the other studies. All studies found that the number of trees converged after age 60, with Çatal (2009)’s values being the most similar to our findings (Figure 7a).
Erkan (1995) obtained the total stand volume values that were most similar to our findings. Total stand volume was also consistently lower in the study by Alemdağ (1962). Our