Effect of aspect and slope on growth in an Anatolian black Pine [Pinus nigra J.F. Arnold subsp. pallasiana (Lamb.) Holmboe] plantation

Abstract

This study aimed to determine the effects of aspect and slope on tree height and diameter at breast height (DBH) in a 28-year-old Anatolian black pine [Pinus nigra J.F. Arnold subsp. pallasiana (Lamb.) Holmboe] plantation. The study was conducted within the boundaries of the Keçiborlu Forest Management Chiefdom, Isparta Regional Directorate of Forestry, Türkiye. Three 10 × 30 m sample plots were established in each of the south-, west-, north-, and east-facing aspects and in each of the 0–5%, 5–20%, and 20–35% slope classes. Tree height and DBH were measured for all trees within the sample plots. The data were analyzed using one-way analysis of variance (ANOVA), and Tukey’s multiple comparison test was used to identify significant differences among groups. Significant differences were found among aspect groups for both tree height and DBH. The highest mean tree height and DBH were recorded on the south-facing aspect, at 7.27 m and 15.49 cm, respectively. A significant difference in tree height was found among slope classes (p=0.008), whereas the difference in DBH was not statistically significant. These findings indicate that topographic characteristics such as aspect and slope may be useful considerations in the planning of Anatolian black pine plantations. Future studies evaluating aspect and slope together with soil properties, slope position, and microclimatic conditions may contribute to a more comprehensive understanding of growth differences in Anatolian black pine plantations.