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. Five slash treatments (slash-free, chipped, small piles, large piles, scattered) were replicated five times at each of two sites, one consisting mainly of ponderosa pine and the other predominantly lodgepole pine. No pine engravers 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 small and large pile treatments. A significantly greater number of invertebrate natural enemies were also found in the scattered slash treatment, where they were approximately six to nine times as abundant as in the small pile and large pile treatments, respectively. No pine engravers were observed colonizing slash in the lodgepole pine treatments where slash was in an advanced stage of drying. At both sites, the use of a feller buncher-delimber during harvest increased the rate of drying of slash, reducing its suitability for pine engraver colonization. West. J. Appl. For.