Regeneration beneath lodgepole pine dominated stands attacked or threatened by the mountain pine beetle in the south central Interior, British Columbia

摘要

We assessed the species composition and abundance of germinants, seedlings, saplings, and larger trees in 167 stands of lodgepole pine (Pinus contorta var. latifolia Dougl ex. Loudon) in south central British Columbia. These stands had either been attacked or were threatened by the mountain pine beetle (Dendroctonus ponderosae Hopk.). The mean density of understory stems varied widely within and between biogeoclimatic ecological classification (BEC) subzones, but increased with increasing climatic moisture and elevation. Seedlings were the most abundant class of regeneration followed by saplings and poles. Subalpine fir (Abies lasiocarpa (Hooker) Nutt.) was the dominant regeneration species in seven of 11 subzones. A threshold density of 600stems/ha of acceptable stems was exceeded in almost half of all plots. Germinants were infrequent except in the moist and high elevation subzones. Species other than lodgepole pine were common in the canopy of sample stands, with the exception of the very dry cool Montane Spruce.The abundant advance regeneration and presence of non-pine species in the canopy of many stands provides forest managers with flexibility in planning mountain pine beetle salvage operations. These stand components contribute to achieving both timber and non-timber objectives but subalpine fir is not highly regarded as a future timber species and protection of this species in future stand operations is a controversial issue. The low level of both stand components in the extensive dry Montane Spruce subzones creates challenges in designing plans for timber salvage or forest renewal.