Shrub and Perennial Outplanting Study

Though successful deployment in reclamation areas is required for stakeholder and regulatory expectations to achieve locally common boreal forest ecosystems, there are uncertainties around outplanting success for many understory species. For some, there is insufficient experience to gauge success, and for others, survival rates are poor or inconsistent; overall, there is a lack of information about the problem’s magnitude and causes of poor establishment success. This project explored feasibility of restoring forest understories through seedling planting in two stages: (1) quality of nursery grown boreal shrub seedlings was examined by testing whether seedling quality attributes that are commonly used to evaluate tree seedlings and their outplanting performance can be applied to shrubs, and (2) field trial monitoring of survival and growth of nine shrub species outplanted onto seven different sites that varied in age since reclamation, canopy tree species, and edaphic conditions.

Conclusions: (1) in the nursery, attributes selected to evaluate shrub seedling quality did not correlate with performance when seedlings were grown under no stress conditions; survival was very high, except in two species which showed evidence of poor seedling quality, suggesting that for some species, nursery protocols need to change to produce better planting stock; (2) in the outplanting experiment, larger seedlings performed better, but site conditions rather than size had greatest influence on seedling performance; and (3) understory shrub seedlings survived and grew best on young reclamation sites with no tree canopy or competitive vegetation; this is encouraging, but might not reflect ability to maintain themselves as competitive conditions develop – seedlings planted on older (11-16 years), more competitive reclamation sites experienced highest mortality, while in seedlings planted on older reclamation sites (> 30 years) where a closed tree canopy had grown, survival was high, though growth was slightly reduced compared to young, open sites.