Sami Lamminen
Finnish Forest Research Institute, Joensuu Research Unit, Box 68, 80101 Joensuu, Finland.
Matti Sirén
Finnish Forest Research Institute, Vantaa Research Unit, Box 18, 01301 Vantaa, Finland.
Abstract
In Finland, peatland logging is generally conducted during the winter due to the inherently low soil bearing strength under unfrozen soil conditions. Mild winters the past several years have raised the issue of operations on unfrozen peatlands. Modifying wheeled logging equipment such that it was able to operate cost-effectively on sensitive sites and then switch back to normal, base machine specifications at other times would be a significant advantage.
The mobility and rut formation of a conventional 8-wheeled forwarder was studied with four different sets of chain/track equipment. Additionally, the forwarder was equipped with a rear, add-on axle resulting in a 10-wheeled forwarder. That modified forwarder was tested with the widest set of tracks on an abandoned peat field and on a pine bog.
Results indicate that the forwarder modifications significantly increased mobility and decreased rut formation on the test soils. On the pine bog, the 10-wheeled forwarder had the best mobility and the least rut formation of all equipment tested.
