Six year efficacy of silvicultural treatments to control American beech regeneration in stands affected by beech bark disease in Ontario, Canada

High beech regeneration density is a concern in northern shade tolerant hardwood forests. High densities of beech ( Fagus grandifolia Ehrh) regeneration can crowd out other desirable species, such as sugar maple ( Acer saccharum Marsh.), and jeopardize long-term sustainability since beech is under threat from beech bark disease ( Cryptococcus fagisuga/Neonectria spp. Complex). We examined the efficacy of three tending (no tending, brush saw, and basal bark herbicide) and two timing and harvesting (deferred 5 years post-single tree selection harvest, concurrent with uniform shelterwood harvest) treatments on reducing beech regeneration density and promoting sugar maple regeneration density over 6 years. Six years after tending, we found that large beech regeneration density was reduced, medium beech regeneration density had recovered to pre-tending levels in most treatments, and small beech regeneration density remained unaffected. Tending treatments had no effect on any size class of sugar maple regeneration density but the uniform shelterwood harvest promoted medium sugar maple density more than the single-tree selection harvest. Despite this increase, in all treatment combinations sugar maple regeneration densities remained below stocking targets. Our results suggest that while tending treatments can temporarily reduce beech regeneration densities, sugar maple is unable to take advantage of the increased growing space.