Managing Understory Vegetation for Maintaining Productivity in Black Spruce Forests: A Synthesis within a Multi-Scale Research Model

Abstract

Sustainable management of boreal ecosystems involves the establishment of vigorous tree regeneration after harvest. However, two groups of understory plants influence regeneration success in eastern boreal Canada. Ericaceous shrubs are recognized to rapidly dominate susceptible boreal sites after harvest. Such dominance reduces OPEN ACCESSForests 2013, 4 614 recruitment and causes stagnant conifer growth, lasting decades on some sites. Additionally, peat accumulation due to Sphagnum growth after harvest forces the roots of regenerating conifers out of the relatively nutrient rich and warm mineral soil into the relatively nutrient poor and cool organic layer, with drastic effects on growth. Shifts from once productive black spruce forests to ericaceous heaths or paludified forests affect forest productivity and biodiversity. Under natural disturbance dynamics, fires severe enough to substantially reduce the organic layer thickness and affect ground cover species are required to establish a productive regeneration layer on such sites. We succinctly review how understory vegetation influences black spruce ecosystem dynamics in eastern boreal Canada, and present a multi-scale research model to understand, limit the loss and restore productive and diverse ecosystems in this region. Our model integrates knowledge of plant-level mechanisms in the development of silvicultural tools to sustain productivity. Fundamental knowledge is integrated at stand, landscape, regional and provincial levels to understand the distribution and dynamics of ericaceous shrubs and paludification processes and to support tactical and strategic forest management. The model can be adapted and applied to other natural resource management problems, in other biomes.

The effect of biochar management on soil and plant community properties in a boreal forest

“…However, in support of our fourth hypothesis, P. sylvestris seedling growth and germination rates of four sown species ( P. sylvestris , P. contorta , P. abies , and B. pendula ) were strongly impaired in the plots where vegetation cover was the greatest (i.e., the unmixed plots). These results highlight the importance of ground layer vegetation in determining tree establishment success in boreal forests (Thiffault et al ., ).…”

Response diversity, functional redundancy, and post‐logging productivity in northern temperate and boreal forests

“…For instance, black‐spruce‐dominated stands are known to be at a considerably greater risk of decreased productivity due to paludification and invasion by ericaceous shrubs (Thiffault et al. ). Therefore, these negative effects on productivity associated with black spruce likely mediate the observed negative relationship between coniferous response diversity and post‐logging productivity.…”

Ecosystem management in paludified boreal forests: enhancing wood production, biodiversity, and carbon sequestration at the landscape level

“…Restricting circulation of logging machinery to evenly-spaced trails, such as during careful logging around advanced growth, leaves the understory vegetation and soils intact between the trails, which may induce rapid proliferation of ericaceous species such as R. groenlandicum and K. angustifolia (Lorente et al 2012). These species may compete directly with trees for nutrients, and indirectly by modifying humus quality and inducing allelopathic effects (Thiffault et al 2013). In contrast, by disturbing the organic layer in which the roots of ericaceous shrub proliferate (Mallik 1993;Hébert and Thiffault 2011), clearcutting can limit shrub proliferation and their negative effect on tree growth.…”