Quaking aspen (Populus tremuloides Michx.) is an early successional species that thrives after disturbance, but the natural disturbance regime of many western U.S. aspen forests (historically mixed- to high-severity fire) has been interrupted by human intervention, including fire suppression. Many western landscapes now have a disproportionate amount of late seral-stage mixed aspen-conifer forest. To regenerate aspen and reduce fuel loading, managers have recently applied a non-traditional treatment, called roller-felling, in late-seral stage aspen forests in Utah. We examined one- and two-year impacts of this stand-replacing mechanical treatment on aspen regeneration. Complete overstory removal from roller-felling generally resulted in high-density colonization of aspen suckers one year after treatment, occurring even where low proportions of overstory aspen were present prior to treatment. Lower slash retention, higher mineral soil exposure, and pre-treatment stand age were positively related to increased aspen stem density one-year post-treatment. Decreased machinery traffic was correlated with increased aspen stem density two years after treatment. Ungulate populations inflicted heavy damage on post-treatment regeneration in both years, highlighting the importance of site context, as browsing may impede stand development and diminish forest recovery. Our results suggest roller-felling largely emulated other stand-replacing disturbances (e.g., windthrow or fire) and can serve as an alternative treatment to regenerate aspen where site conditions are appropriate.
Trudgeon et al. (Mon,) studied this question.