Pine engraver (Ips pini) Colonization of Logging Residues Created Using Alternative Slash Management Systems in Western Montana

In this study, we observed effects of various slash treatments on pine engraver colonization. Fiveslash treatments (slash-free, chipped, small piles, large piles, scattered) were replicated five times at each oftwo sites, one consisting mainly of ponderosa pine and the other predominantly lodgepole pine. No pineengravers were found in slash-free or chipped slash treatments at either site. At the ponderosa pine site,significantly more pine engraver attacks and galleries were found in the scattered slash treatment than in smalland large pile treatments. A significantly greater number of invertebrate natural enemies were also found inthe scattered slash treatment, where they were approximately six to nine times as abundant as in the small pileand large pile treatments, respectively. No pine engravers were observed colonizing slash in the lodgepole pinetreatments where slash was in an advanced stage of drying. At both sites, the use of a feller buncher–delimberduring harvest increased the rate of drying of slash, reducing its suitability for pine engraver colonization. West.J. Appl. For. 17(2):96–100.Key Words: Slash management, natural enemies, bark beetles.