The Itcha-Ilgachuz Research Project was initiated in 1995 in the west Chilcotin region of central British Columbia to test variants of group selection and irregular group shelterwood silvicultural systems for managing lodgepole pine (Pinus contorta var. latifolia) forests for timber and northern caribou (Rangifer tarandus caribou Gmelin, northern ecotype) winter habitat. The density, distribution, and growth of naturally regenerated lodgepole pine was monitored in the small harvested openings and the forested matrix of the silvicultural systems treatments, in forested control units, and in adjacent clearcuts over the course of the mountain pine beetle epidemic (2003-2008) and 5 years after.
Natural regeneration in the very dry, cold Sub-Boreal Pine-Spruce (SBPSxc) biogeoclimatic subzone was sufficient to restock small harvested openings and produce a stocked stand in the understorey of a mature stand that was severely impacted by mountain pine beetle. In this subzone, advance regeneration will play an important role in future stand development, more so than ingress resulting from disturbance. In the higher elevation very dry, very cold Montane Spruce (MSxv) subzone, natural regeneration was not abundant enough to stock harvested openings or mountain pine beetle impacted stands. Post-disturbance ingress will be the predominant component of the understorey in this subzone. Our results suggest that recovery after the beetle outbreak will be a slower process in the MSxv than in the SBPSxc due to reliance on new recruits. Better seedling growth and condition in the MSxv, however, may help mitigate the slower recovery rate. The forest canopy, even with considerable mortality, had a significant impact on seedling growth and condition compared to clearcut conditions. The last assessment, completed 5 years after the outbreak, showed that seedlings in all locations, but particularly in the harvested openings, had improved growth and vigour, which suggests that they are responding to the increased site resources. This study shows that pathways of stand recovery after the mountain pine beetle epidemic in the west Chilcotin will differ depending on biogeoclimatic and pre-epidemic stand conditions.
Download Technical Report 88 (814 KB)
To view this document you need the current version of
Adobe Acrobat Reader, available free from the
Adobe Web Site.
Updated July 21, 2015