Legacy effects of precommercial thinning on the natural regeneration of next rotation balsam fir stands in eastern Canada

Abstract

The Green River precommercial thinning (PCT) trial was established between 1959–1961 in New Brunswick (Canada) within natural balsam fir ( (L.) Mill.)-dominated stands. Three silviculture scenarios differing only by the increasing nominal spacings of PCT treatments (1.2 m, 1.8 m, 2.4 m) were compared to an unthinned control within randomized replicates that were clearcut harvested in 2008 and treated with herbicide in 2011. During the fourth post-harvest growing season, we assessed regeneration, competing vegetation and coarse woody debris (CWD; differentiated between large woody debris and slash) to assess the legacy effects of PCT on regeneration of next rotation stands. Our results confirmed that silviculture scenarios including PCT significantly increased conifer stocking in treated plots compared to control conditions, but only in the 1.8 m nominal spacing. Considering that treated and untreated stands were fully stocked, we conclude that PCT using the spacing gradient tested has no legacy effect on the regeneration of next rotation natural balsam fir stands. Given the known sensitivity of balsam fir to future climate conditions in this region, we suggest that future treatments should promote tree species diversity to support ecosystem resilience to climate change by favouring more warm-adapted species, such as some hardwoods.Abies balsamea

Legacy of thinning on woody species composition and structure in southern Appalachian Mountain hardwood forests: restoration implications

“…Legacy effects associated with past forest management practices may persist for decades and can affect structure, composition, and function of ecological attributes, including understory vegetation (Perring et al 2018), tree regeneration (Canuel et al 2019), growth and productivity (Devine & Harrington 2009), dead and downed wood (Muurinen et al 2019), and soil properties (James et al 2018). These legacy effects, in turn, influence how forests respond to disturbance (Mausolf et al 2018), including restoration activities, and could possibly constrain future ecological processes and conditions (Royo & Carson 2006; Garbarino & Weisberg 2020).…”

The introduction, the link between applied research and a successful publication

“…Several examples illustrate this point. The recent article by Canuel et al (2019) in Silva Fennica examined the legacy effects of pre-commercial thinning of balsam fir (Abies balsamea) on the regeneration of the subsequent stands in southeastern Canada. While this may seem a very narrow topic, the way it is presented highlights its potential interest for forestry professionals and researchers in general.…”