Stand and landscape-level simulations of mountain pine beetle ( Dendroctonus ponderosae) and salvage logging effects on live tree and deadwood habitats in south-central British Columbia, Canada

Abstract

The effects of mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins) and salvage logging were modeled on live trees and deadwood habitats, including snags and coarse woody debris (CWD), in stands that varied by lodgepole pine ( Pinus contorta Dougl.) dominance, age and growing site quality. Results were projected on a lodgepole pine-dominated landscape in south-central British Columbia, Canada to examine differences in the density, distribution and type of live tree and deadwood habitats following the MPB outbreak and salvage logging. Tree mortality caused by MPB varied considerably with percent pine and factors that affect tree size, including tree age, size and growing site. Mortality ranged as much as 38–86% even in 100% pine stands, creating a range of residual live tree levels and a pulse of snags that contributes to the increased total and well-decayed CWD volumes over time. In contrast, salvage logging consistently reduces large live trees and snags and contributes to long-term declines in both total and well-decayed snag and CWD volume. Compared to the MPB outbreak, widespread salvage logging will leave a paucity of live trees, snags and CWD in cutover areas on the landscape. This becomes a concern if ongoing natural disturbances and timber harvest deplete remaining mature forests and few intermediate aged forests (40–100 yrs) exist to recruit new live tree and deadwood habitats in the future. Careful planning prior to salvage logging is required to maintain and recruit adequate live tree and deadwood habitats to support native wildlife in future landscapes.