Effects of forest roads on foliage discoloration of oriental spruce by Ips typographus (L.)

The aim of the study was to investigate the effects of forest roads on foliage discoloration levels of oriental spruce Picea orientalis (L.) Link by Ips typographus (L.), considering location, ground slope and ground surface type of the spruce stands. The study was carried out over two years (2006-2007) in Artvin-Hatila National Park, Turkey. A total of 480 spruce trees from 12 stands were sampled. The results of the study were as follows: 1) locations of the trees (down-slope, up-slope, and forest interior plots) and ground surface types of the area (rocky and non-rocky grounds) significantly affected the foliage discoloration levels, 2) mean foliage discoloration level of trees were highest in the down-slope plots followed by up-slope and forest interior plots, 3) mean foliage discoloration level of trees grown up on the rocky stands were significantly greater than those on the non-rocky stands, and 4) mean stem volume of the trees with the foliage discoloration level 4 (death) were significantly greater than those with the other foliage discoloration levels (0, 1, 2, 3).