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ŠUMARSKI LIST 3-4/2023 str. 11     <-- 11 -->        PDF

Mersin Regional Forest Directorates in the central Mediterranean region of Turkey. The provinces of Antalya and Mersin, where the stands are located, lie between 33˚-35˚ east longitude and 36˚-37˚ north latitude (Figure 1). In the central Mediterranean region (Antalya and Mersin), there are 1,981,596 ha of forested area, of which 1,060,827 ha (53.5%) is Calabrian pine stand. 761,194 ha (38.41%) of this area are pure Calabrian pine stands (Directorate General of Forestry, 2018). The other dominant tree species are juniper 19.4%, Lebanon cedar 15.2%, oak species (Quercus coccifera, Quercus cerris, Quercus infectoria, Quercus ilex, and Quercus libani) 14.4%, Cilician fir 6.0%, Black pine 4.9%, and other deciduous trees 7.7% (maple, hornbeam, olive, black locust, wild olive, carob). The study area has a Mediterranean climate with hot and dry summers and mild and rainy winters. The average annual rainfall is 1069.8 mm/m² and 585.4 kg/m² for Antalya and Mersin provinces, respectively. The elevation of the study area varies from 79 to 1473 m (= 578.7 m) and the slope ranges from 2% to 150% (=40.9%). 262 of the sample plots are in shady aspects and 224 of the sample plots are in sunny aspects.
Data from 486 temporary sample plots within even-aged stands found in the Antalya and Mersin Forest Regional Directorates were used in this context. Additionally, 972 measurements of two trees selected for harvesting (including the dominant tree to determine site index and the tree to determine the mean stand diameter) in each plot were used (Kahriman et al., 2016b). The number of sample plots was determined considering the combination of nine age classes (0-10, 11-20, 21-30, 31-40, 41-50, 51-60, 61-80, 81-100, > 100 years), three SI classes (height class I: 23.5< m, height class II: 16.5-23.5 m, height class III: < 16.5 m), three closure classes (11-40%, 41-70%, > 70%) with three replicates in two regional forest directorates.
Depending on the stand structure, the sample plots in this study range in size between 400 m2 for crown closure >70 %, 600 m2 for 41-70%, 800 m2 for 11-40%, and 800-2000 m2 for stands that had standing seed trees and seedlings in the transition stage. On each sampling plot, diameters at breast height (dbh) of all trees were measured. Additionally, 10–15 trees from each sampling plot were selected to have their height, age counted by annual rings from core samples in addition to the age up to the height of dbh, double bark thickness on opposite sides, and most recent 5-year diameter growth measured at breast heights. These trees were evenly distributed across the diameter classes of 0-4 cm, 4-8 cm, 8-12 cm, 12-16 cm, …., 96-100 cm. In order to create stand growth models in the form of yield tables, the values for quadratic mean diameter (), mean height (), dominant height (h100), number of stems (N), basal area (BA), stand volume (V), stand age (t), site index (SI), and stand density (sd) were calculated. Descriptive statistics of variables measured on individual trees (dbh, height, age, double bark thickness, and increment) and stand variables estimated from these measurements (stand age, site index, stand density, root mean square diameter, mean height weighted