ABSTRACT
A retrospective study was undertaken in an old Mountain Pine Beetle (MPB) attacked forest to gain insight in stand dynamics post-beetle attack. Extent of mortality, regeneration delay, release of advance regeneration and other surviving residual trees and post-beetle stand growth was determined. Five plots were established in each of 22 stands representing a range of MPB attack intensity. Pre-attack basal area varied between 29 and 58 m2 ha-1. The percent of basal area killed by beetles varied from 42 to 100% with most stands between 60 and 80%. Six stands exceeded 80% basal area mortality and 3 stands were below 60% mortality. In 2007, twenty-five to 30 years after attack basal area varied between 4 and 51 m2 ha-1. Five stands, ranging in mortality at time of attack from 51 to 79%, had fully recovered their pre-attack stand basal area. Four stands, ranging in mortality at time of attack from 68 to 100%, had poor basal area recovery. Growth release on surviving trees exhibited species and size variability. Release of surviving lodgepole pine trees was often dramatic. Recruitment of new regeneration post-beetle attack was often, but not always, delayed by 5-10 years. Densities of post-beetle regeneration were often high in 2007. Based on age of understory trees in 2007, there was little advance regeneration in these forests at the time of the beetle attack.
