... precipitation rates, these machines are likely to remain the most common type of skid-ding machine used. In mountainous and steep areas, the terrain slope is an important factor that a ects operational ... ef-ficiency, costs and erosion. It may also a ect the soil compaction, so in planning forest operations and aligning skid trails the terrain slope may be an im-portant consideration for protecting soil ... soil compaction, rutting and forest floor removal was evaluated on a skid trail in the natural forest of north of Iran. Combination of two levels of slope < 20% (SC1) and > 20% (SC2) and three...