Effect of Ground Slope, Stump Diameter,and Species on Stump Height for Feller-Buncher and Chainsaw Felling
Authors
Han-Sup Han
University of Idaho
Chad Renzie
University of Northern British Colombia
Abstract
Stump heights were measured on six clear-cut blocks in the central interior of British Columbia using a systematic sampling method. Felling method, ground slope, species and stump diameter were analyzed to determine their effect on stump height. Mechanized felling with a feller-buncher resulted in lower stumps by 5.5 cm on average than those from manual felling with a chainsaw. The wide range (9.6 cm to 23.4 cm) of the average stump heights sampled from six clear-cut units indicates that other factors such as slope, species and stump diameter may influence stump height. When considering tree species, the feller-buncher left lower stump heights for subalpine fir and white spruce, while chainsaw felling resulted in lower stumps for Douglas-fir. Average stump and feller-buncher stump heights tended to increase as percent slope increased up to 45%, but the opposite trend was found in chainsaw felled sites with slopes greater than 45%. Both feller-buncher and chainsaw felling methods resulted in lower stumps as the average stump diameter increased. On ground slopes less than 30% and stump diameters between 30 and 70 cm, our analysis suggested that feller-buncher felling resulted in lower stump heights than chainsaw felling. Chainsaw felling can cause stump-pulls, slabs, and unevenness at the bottom of the tree being felled, requiring a further reduction of wood that could potentially be used for solid wood products. Feller-buncher felling, however, results in greater wood volume waste as the result of a thicker saw blade kerf than does chainsaw felling.
