ALBERT

Description: Residual stand damage was evaluated following partial cutting with a mechanical and a conventional harvesting system in a northern hardwood stand in Maine. Damage from harvesting using a swing to bunch feller–buncher and grapple skidder was compared with damage from a chainsaw and cable skidder operation. Harvesting resulted in actual residual basal areas of 10 and 16.5 m2/ha in a heavy and light conventional treatment, respectively, and in 9 and 6.9 m2/ha in two mechanized treatments. The proportion of stems wounded averaged 22–44% in the conventional, and 20–31% in the mechanized operation. Wounds were significantly (p 〈 0.05) longer in the heavy conventional [Formula: see text] treatment than in light conventional [Formula: see text] and mechanized ([Formula: see text] and 60.2 cm) treatments. Wounds were located higher on the stems in the 9 m/ha mechanized [Formula: see text] than in the 10 m2/ha conventional treatment [Formula: see text]. A separate survey of the mechanized harvest showed that season of harvest (winter vs. summer) significantly affected wound location and the wound width to tree circumference ratio. A model was developed that relates harvesting treatment (light and heavy conventional and two heavy mechanical), species, distance of a stem from the edge a skid trail or access corridor, and initial stand basal area to the probability of injuring an individual stem. Mechanized harvesting using equipment with long-reach swing to bunch felling capability appears to be better than some other mechanical systems, and no worse than conventional harvesting systems, but the need to further reduce damage levels is evident.