There's Life After Pine Beetles
Lodgepole pine stands heavily hit by mountain pine beetles then left unmanaged for 25 years have become forests comprising an array of tree ages interspersed with standing and fallen snags. With their complex structure, these forests now provide valuable wildlife habitat and in some cases are also growing harvestable volumes of timber.
Mountain pine beetles killed 70 percent of the mature pine in 1979 at sites studied near Quesnel, British Columbia, in the dry Sub-boreal Pine Spruce biogeoclimatic zone. Of the trees that survived, 60 percent were lost in 2005 when beetles revisited. Altogether, 85 percent of the pine overstory succumbed to beetles.
The proportion of dead trees left standing varies considerably among stands, ranging from 0 to 80 percent of the snags. With up to 166 m³/ha of decomposing logs lying on the ground, the debris is not considered a fire hazard. Most of the mature overstory pines that survived the beetles boosted their diameter growth rate by an average of 44 percent during the following 25 years.
The understory of pine saplings remaining after the beetle infestations were augmented with more vigorous pine regeneration once the canopy opened. Although the new trees sprouted in scattered clusters, one-third of the sites examined meet a forestry restocking standard of 1000 stems per ha. Regrowth is enough in 30 percent of the stands to provide harvestable volumes of wood for the mid-term.
Forest Practices Board. 2007. Lodgepole Pine Stand Structure 25 Years after Mountain Pine Beetle Attack. Forest Practices Board Special Report FPB/SR/32. Victoria, BC.