Canadian Forest Service Publications
Management legacy in the understory of North American mixed boreal regenerating stands. 2014. Aubin, I.; Deshaies, O.; Cardou, F.; Sirois, L. Forest Ecology and Management 320:129-137.
Issued by: Great Lakes Forestry Centre
Catalog ID: 35414
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In the global context of planted forest expansion, the ability of artificially regenerated forests to stand-in for natural forests has become a central question for forest managers. Although few studies have examined their conservation potential, extensive planted forests cover a significant portion of North-American mixed boreal forests. We study the composition, functional assemblage, and vertical structure of understory communities in even-aged, mid-rotation, planted and naturally regenerated mixed boreal stands typical of extensive management (Québec, Canada). Our results show that more than 20 years after harvest, species composition and functional assemblage still differ between stand types while understory structure does not. Planted stands exhibit a higher prevalence of traits and species typically associated with younger stands. Sensitive species such as Oxalis acetosella ssp. montana and_ Monotropa uniflora_ occurred less often in planted stands while the reverse was true for a portion of species with the potential to form a recalcitrant layer. This suggests that the understory of planted sites may require more time before reaching compositional and functional attributes comparable to those of naturally regenerated stands. This delayed maturation has implications for forest management, particularly under increased management intensity scenarios.
Plain Language Summary
The functional trait approach has been developed to better understand plant communities by simplifying each species into a suite of characteristics that matter for ecosystem processes. We use this approach in combination with traditional taxonomic and structural diversity metrics to look at the effect of management intensity on the understory plants of the mixed-boreal forest (Quebec). We compare the understory plant communities of naturally regenerated stands with planted stands, both in Yellow birch- and White birch-dominated stands, twenty years after harvest (Bas Saint-Laurent Region, Quebec). We find that there is no significant difference in the list of species present at these sites. We find differences in the relative importance of species between naturally regenerated and planted sites, with planted stands showing higher proportions of understory species typical of younger-aged stands. Overall, we conclude that disturbances associated with planting might delay maturation of the understory community, and suggest potential implications for the development of recalcitrant understory layers.