In 1997, FERIC studied a partial cutting operation in the Interior Cedar-Hemlock biogeoclimate zone, on a site west of Kitwanga, B.C. The operation used a Skylead C40 16000 skidder-mounted yarder and Mini-Maki II radio-controlled carriage in a standing skyline configuration and in single-and multi-span applications. The study provided information on productivity and costs for the harvesting system, impact on soil surface conditions, and damage to the residual stand. Productivity functions were derived to predict yarding productivity and costs over a range of operation conditions.
This report summarizes a pilot study that investigated how loads that are applied to skyline systems in second-growth thinning operations affect the line tensions and stress distribution in the backspar. The maximum tension in the skyline occurred when the turn was fully suspended under the carriage. In the backspar that was examined, compression was the critical stress. By recognizing how the critical loads produce stresses on backspars, procedures can be developed that will limit these stresses.
The survey objective was to describe and compare how common cable-yarding systems are currently being applied in Coastal British COlumbia with respect to access requirements. This Field Note summarizes the survey results.
FERIC conducted six case studies on long-distance skyline yarding systems operating near Terrace, British Columbia in 1995. The studies were conducted to investigate why skyline operators in B.C. are experiencing a wide range of productivities and costs. The study sites were located in the wet submaritime subzone of the Coastal Western Hemlock biogeoclimate zone (CWHws).
Estimates of fuel consumption were made for six harvesting systems used in typical coastal British Columbia forest operations. Five of the systems - grapple yarding, highlead yarding, skyline yarding, helicopter yarding, and loader forwarding - were in clearcuts. Another system consisted of loader forwarding in a partial cut. The proportion of wood harvested by each of these harvesting systems was also determined, based on a survey of coastal British Columbia forest companies. This study was part of a larger research effort on life-cycle analysis addressing the impact of forest operations on the environment.
Between December 1993 and March 1994, FERIC monitored hand-falling and skyline-yarding operations in a 9.6-ha second-growth stand of Douglas-fir, western hemlock, and western redcedar in Coastal British Columbia. The study measured falling and skyline yarding productivities, identified factors influencing productivity, recorded extracted volumes by timber grades, and conducted post-harvest site assessments. Simple productivity prediction models were developed for falling only, falling and processing, and skyline yarding.
In April 1999, the Western Division of FERIC held an implementation workshop for its advisory committee members. Twenty-four presentations were made by 26 speakers, including topics on planning, road construction and deactivation, harvesting and thinning operations and log hauling. This proceeding summarizes the material presented at the workshop.