Effect of location and diameter of different tree species on bole decay due to logging wounds in Nav-e Asalem forests, Iran

Logging secondary damages on remained trees are one of the challenges in management of uneven-aged stands which have been less studied in the northern forests of Iran. In this research decay frequency and volume of bole trees after 15 years from wound occurrence were studied through systematic-random sample plots with 1000m2 plots in the Nav-e Asalem forests, Iran. The conditions of trees were registered in two types: safe and wounded, the wounds were registered in two types: open and decayed; and volume of decayed bole was calculated by Smalian formula. Results indicated that 16.1% of wounds were led to bole decay. Decay frequency and volume were estimated to 5.5 trees ha-1 and 1.7 m3ha-1, respectively, that includes 1.96% of total trees and 0.72% of total stand volume. Coefficients of decay frequency and volume on the base of frequency of logging primary damage (12.2%) were calculated 0.16 and 0.06, respectively. Decay frequency of wounded trees bole were related with tree species, wound location, diameter at breast height (DBH), situation of wounded tree in stand, and slope aspect. Decay frequency and volume in the trees of lime and oak were more than other tree species. Decay frequency was increased by decreasing wounds distance from ground. Decay frequency and volume in the high diameter wounded trees were more than low diameter wounded trees. The wounds on the trees in edge of skid trails were more decayed than the other wounds. Decay frequency of wounded trees on the northern aspect slopes were more than the southern aspect slopes. In general, minimizing of primary logging damages, reducing harvest intensity, increasing logging period, and harvesting bole-decayed trees in the next logging periods are suggested.