FERIC sampled butt-damage on 25 interior felling operations. One hand- faller, 4 shear machines and 20 non-shear machines were sampled. Lumber trim losses (2 X 6-inch basis) to remove damage were predicted as a percentage of total lumber content in the tree. Predicted losses were highest for the shear machines, substantially lower for most non-shear machines and negligible for the hand-faller.
A multi-agency trial was established to determine the impacts of commercial thinning on the growth, yield, and development of white spruce stands. The commercial thinning operation was completed using a Timberjack 1270 harvester and a Timberjack 1210B forwarder. The Forest Engineering Research Institute of Canada (FERIC) monitored the harvesting phase, determined the operational cost and productivity of the harvester and forwarder, determined the residual tree damage, and evaluated the effectiveness of a brushing crew in increasing the productivity of the harvester in areas with high densities of non-merchantable trees.
This report documents the costs and productivities of group-selection harvesting of one-third of a stand in an old-growth cedar–hemlock forest in the interior wet-belt of British Columbia while preserving caribou habitat values. The group-selection harvesting was compared to clearcut and single-tree selection treatments. Harvesting costs were strongly influenced by the merchantability of the harvested stems and the criteria for selecting trees to be harvested. The single-tree selection had the lowest cost because of the selection criteria and merchantability while the group selection had the highest cost. The group selection treatment’s harvesting costs were about 22% greater than for the clearcut treatment.
In November 1998, FERIC, at the request of Spray Lake Sawmills (1980) Ltd., conducted operational and post-harvest monitoring on feathered block boundaries to determine productivities of mechanical felling and residual tree damage.
In response to industry concerns over stem damage caused by harvester heads, FERIC has investigated the head characteristics that are responsible. Although many factors contribute to stem damage, the following are particularly significant: the means of transferring the feed force to the stem, the amount of friction between the stem and the harvester head, the feed roller or track suspension, and the feed roller resistance and slippage. The report summarizes the desirable characteristics of feed devices and provides recommendations on how to select a feed device for various products.
