Woody plant regeneration after blowdown, salvage logging, and prescribed fire in a northern Minnesota forest

Salvage logging after natural disturbance has received increased scrutiny in recent years because of concerns over detrimental effects on tree regeneration and increased fine fuel levels. Most research on tree regeneration after salvage logging comes from fire-prone systems and is short-term in scope. Limited information is available on longer term responses to salvage logging after windstorms or from forests outside of fire-prone regions. We examined tree and shrub regeneration after a stand-replacing windstorm, with and without salvage logging and prescribed fire. Our study takes place in northern Minnesota, USA, a region where salvage logging impacts have received little attention. We asked the following questions: (i) does composition and abundance of woody species differ among post-disturbance treatments, including no salvage, salvage alone, and salvage with prescribed burning, 12 years after the windstorm?; (ii) is regeneration of Populus, the dominant pre-blowdown species, inhibited in unsalvaged treatments?; and (iii) how do early successional trajectories differ among post-blowdown treatments? Twelve years after the wind disturbance, the unsalvaged forest had distinctly different composition and abundance of trees and woody shrubs compared to the two salvage treatments, despite experiencing similar wind disturbance severities and having similar composition immediately after the blowdown. Unsalvaged forest had greater abundance of shade tolerant hardwoods and lower abundance of Populus, woody shrubs, and Betulapapyrifera, compared to salvage treatments. There was some evidence that adding prescribed fire after the blowdown and salvage logging further increased disturbance severity, since the highest abundances of shrubs and early successional tree species occurred in the burning treatment. These results suggest that salvage treatments (or a lack thereof) can be used to direct compositional development of a post-blowdown forest along different trajectories, specifically, towards initial dominance by early successional Populus and B.papyrifera with salvage logging or towards early dominance by shade tolerant hardwoods, with some Populus, if left unsalvaged.