This report describes a joint FERIC, MER study designed to assess the effect of wide tires in skidding and scarification work on both soft ground and steep slopes. Trials under these site conditions were conducted in the Abitibi-Temiscamingue and Saguenay-Lac St.Jean Regions of Quebec respectively, in 1984. The performance of wide tires was compared to that of conventional tires with chains on cable skidders of equal size. Comparison criteria were productivity, gradeability and stability on slopes, fuel consumption, ground disturbance and effect on advance regeneration during skidding; and productivity, gradeability and stability on slopes and subsequent plantability when pulling scarification equipment.