A search for better competitiveness in mechanized early cleaning through product development: evaluation of two Naarva uprooters

Naturally regenerated broadleaf saplings are removed from planted spruce stands to enhance their productivity and quality. Early cleaning is typically carried out motor-manually with brush saws, but a shrinking labor force and economic pressures have spurred the development of machinery that can perform this task quickly, cheaply, and to a high standard. In Finland, Naarva uprooters are currently used in early cleaning. The uprooter devices are attached to harvester booms. They grip and lift a bunch of sprouts from the ground and break their roots, thereby preventing their regrowth. However, their efficiency has to be explored in terms of the quality of cleaning in various situations. We evaluated the productivity of two Naarva uprooter models (the P25 and the P55) in a work-study setting and found that an uprooter cleans at an average rate of one hectare per 6.3 productive work hours under average conditions. Productivity and quality of work decreased when the density and mean height of broadleaf sapling...