UDK 630*38:551.311.21          625.711.84:551.311.21 Tractor roads are often, due to un-implementation of appropriate rehabilitation measures, exposed to erosion processes of various intensity. These processes can be particularly expressed upon completion of forest harvesting works if natural conditions also have such character which favors intensification of erosion process. Intensification of erosion processes on tractor roads in post-exploitation period most often occur in cases when surface water appears on ruts. More intensive coverage occurs in cases when tree crowns do not cover tractor roads, i.e. if larger opening (of forest crop) is in close vicinity of tractor road, which enables larger presence of light and more intensive vegetation growth. This document applies erosion process intensity degree method and assessment of degree of coverage or coverage by litter. For assessment we used a scale from 1 to 5 (REBULA, 1991). Erosion intensity degree on observed locations goes from 1,86 to 3,73. Coverage of tractor roads by grass vegetation or coverage by litter is in range from 4,91 to 1,86.

UDK 582.475:581.4(497.6 Olovo) The research has been carried out in a formal experiment with silver fir near Očevje-Olovo, with nine provenances originating from natural BiH population of 22 years of age. The research observed following provenances: communities from the area of Bugojno, Bosanski Petrovac, Olovo-Palež, Olovo-Klis, Pale, Konjic, Fojnica, Sokolac, and Prozor. The analysis of diameter on the root collar found that there are statistically significant differences among the provenances. It was also found that the biggest diameter on the root collar was on the provenances of Fojnica, with 75.6 mm, whereas the smallest was on the provenances of Olovo-Klis, with 65.2 mm. In terms of breast height diameter, some statistically significant differences were also found, so that the biggest diameter was on the provenance of Fojnica, with 47.0 mm, whereas the smallest value of this feature was on the provenance of Pale, with 41.6 mm. The analysis of the height of different provenances for the testing period, 1999 – 2005 (7 years), suggested statistically significant differences among the provenances. The biggest value was on the provenance of Bosanski Petrovac, with 407 cm, whereas the smallest height was on the provenance of Olovo-Klis, with 364 cm. The results obtained during this research provide valuable information, which can be used as indicators for successful differentiation of silver fir.

UDK 630*56:630*11(497.6)          631.442.2:630*56(497.6) Research results of the stand volume increment changes in mixed forests of beech, fir and spruce on limestone and dolomite in Federation of Bosnia and Herzegovina (FB&H), is presented in this work. Impact of different factors to volume increment value was investigated: habitat quality, values - indicators of structural characteristics particular forest stands, and orographic characteristics if the terrain. Impact of climate differences was investigated trough position of the forests stands in particular ecological-vegetation regions in B&H. Research was done on example of 799 forest stands, trough complex methods of multiple regression analyses, and variance analyses (ANOVA), The results shows that volume increment of the forest stands, besides taxation values: basal area, relative share species in volume, average diameter of the trees, medium height of the trees 50 cm in diameter, significantly depend of the altitude and belonging to particular ecological-vegetation regions in B&H. The result of the analyses is complex model for forest stand volume increment assessment. It was concluded that volume increment of these forest is higher about 1 m3/ha, now than 50 years ago, when very similar investigation was done in the same forests.