Group Clearfell Harvest Can Promote Regeneration of Aspen Forests Affected by Sudden Aspen Decline in Western Colorado

An experimental assessment of the use of clearfell harvesting to initiate a regeneration response in commercially managed aspen forests affected by sudden aspen decline (SAD) was conducted in western Colorado in cooperation with the USDA Forest Service. Nine pure commercial quality aspen stands, with three levels of mortality attributed to SAD, were selected (three replicates per mortality level). Half of each stand was clearfelled, and half was left uncut. The aspen regeneration response was monitored for three growing seasons after harvest in the cut and uncut treatments. Cut treatments with low and moderate mortality had the best subsequent regeneration response, and those with the heaviest mortality exhibited the poorest regeneration response. Uncut treatments exhibited very little regeneration response, regardless of the initial overstory mortality level. Dead trees in the uncut overstory were projected to fall within 15 years. These results indicate that it is possible to successfully regenerate aspen forests affected by SAD, provided that treatment occurs before the majority of the aspen are dead.