ARE FOREST OPERATIONS ON STEEP TERRAIN (AVERAGE OF 70% SLOPE INCLINATION) WITH WHEEL MOUNTED FORWARDERS WITHOUT SLIPPAGE POSSIBLE?

A team of engineers and students from the technical University in Goettingen, Foresters, Physicists and an enineer of the Kaessbohrer AG with a winch mounted snow grooming vehicle PistenBully 300 W Polar made a pilotstudy in the forests of the Harz mountains to find out, if the long hidden theory of Dietmar Sohns works. The theory says, that the common forest harvesting machines should go to the trees and the transportation should be done by forwarders like in low lands. It should be possible to compensate the weight disposition on the forest machines with a spill - winch on rack length of 300 - 500 m up to an average slope inclination of 70 %. The pilotstudy showed that it is possible with the PistenBully winch. The sensor controlled winch ranged up to 40 KN, doubled by pulley to 80 kN, worked perfect. The whole study was prepared by a simulation programme of the Technical University. The maximum load of a full packed Forwarder with 25 t went without any slippage over a section of 85 % slope inclination. Several modifications have to be done to make the system perfect for the future.