Effects of elevation and aspect factors on seedling growth parameters in natural regeneration areas of black pine (Pinus nigra Arnold subsp. pallasiana)

This study was conducted to determine the effects of elevation and aspect on seedling growth in natural regeneration areas of Anatolian black pine (Pinus nigra Arnold subsp. pallasiana). The research was carried out in natural regeneration sites selected in Gökmentepe Mevkii, within the boundaries of Mudurnu Forest Enterprise Directorate. The study area included two different elevation zones (800-1000 m and 1000-1200 m) and two different aspects (sunny and shady). A total of 360 seedlings were monitored over two years, and their morphological characteristics, including seedling height, root collar diameter, and sturdiness index, were measured to statistically evaluate the effects of elevation and aspect on seedling development. The results indicated that seedlings growing at lower elevations and in shady aspects exhibited greater height and root collar diameter. Specifically, seedlings at 800 m elevation in shady aspects had the highest average height (15.03 cm at age 2 and 18.12 cm at age 3) and the largest root collar diameter (3.38 mm at age 2 and 4.71 mm at age 3). Moreover, the highest-quality seedlings in terms of sturdiness index were also found at lower elevations and in shady aspects. Variance analysis results revealed that elevation and aspect had statistically significant effects on seedling growth. These findings emphasize the importance of considering topographic factors when planning natural regeneration efforts for black pine forests.