Early Studies of Multi-Tree Handling in Eastern Canada

Abstract

Thinnings are not as common in Canada as they are in most European countries for a variety of reasons, not the least being the high treatment costs. In recent years, FERIC has proposed a host of strategies to reduce the costs of thinnings and thus increase the attractiveness of this treatment. One of these strategies is to use multi-tree handling harvester heads because the use of single-grip harvesters often results in high wood costs when harvesting small stems typical of commercial thinning treatments. Recently introduced harvester heads such as the Waratah HTH-470 HD provide multi-stem felling and processing options that can increase harvester productivity in small trees. This paper describes the early results from FERIC studies of multi-stem heads working in eastern Canada.

During FERIC studies, the ability to handle more than one stem at a time increased machine productivity by an average of 21 to 33% compared with handling stems one at a time. On average, multi-stem work cycles were longer than single-stem cycles, but the ability to process more than one stem at a time in 30 to 40% of the cycles lowered the mean harvesting time per stem. The delimbing quality and the length-measurement accuracy for sawlogs were comparable to those of conventional heads currently on the market.

This technology is thus well suited to final felling of small trees and to commercial thinning because its productivity is less affected than with conventional heads by the small tree volumes. The accumulator that keeps felled stems vertical also provides benefits, since it lets the operator control the fall of the felled stems and thus may reduce the risk of damaging residual stems.

Keywords:

• Multi-stem harvester head
• Waratah HTH-470HD single-grip head
• thinning
• cut-to-length system
• productivity
• Picea marianna
• Abies balsamea
• Pinus banksiana
• Canada