First-year impacts of shelterwood logging on understory vegetation in an old-growth pine stand in central Ontario, Canada

There is evidence in the literature that a variety of logging practices may result in significant short and long-term changes to vegetation in the forest understory, however, these changes are still largely unknown for many forest types. The objective of this study was to determine the short-term effects of shelterwood logging on tree and non-arboreal plant species composition and diversity in both the understory and sapling strata within the Owain Lake Stand of old-growth red and eastern white pine located in Temagami, Ontario. The most significant changes were increases of white birch (800%), red maple (363%) and bracken fern (110%) in the understory. The most significant decreases within the understory occurred in mosses and liverworts (110%), Canada mayflower (49%) and starflower (28%). Bracken fern, red maple, and bush honeysuckle were the three most abundant species in the post-harvest understory plant community and will probably increase in their abundance under the present disturbed condition. A second shelterwood cut in 20 to 40 years may further facilitate an increase in these three species primarily by increasing light levels at the forest floor. All three species are very vigorous and are likely to dominate the forest understory until the upper canopy closes resulting in decreased light intensity at the forest floor.