Effect of harvest intensity on development of natural regeneration and shrubs in an Ontario boreal mixedwood stand

Modelling stand development after partial harvesting in boreal mixedwoods of eastern Canada

“…Besides the low initial densities of conifer regeneration in the pure aspen stands, the presence of mountain maple impaired the recruitment of shade tolerant conifers into larger tree layers and is likely at least partly responsible for lower stand basal area than the mixed aspen stands after 25 and 50 years of simulation. The adverse impact of high woody shrubs such as mountain maple on shade tolerant conifer recruitment and growth has been well documented for eastern Canadian boreal mixedwood (MacDonald et al, 2004;Kneeshaw and Prévost, 2007;Bose et al, 2014b). Moreover, the pure aspen stands in the study site had fewer conifer seed trees than the mixed aspen stands, which also would affect conifer recruitment over the long term.…”

Eleven-year responses of a boreal mixedwood stand to partial harvesting: Light, vegetation, and regeneration dynamics

“…An overstory canopy reduces temperature and moisture extremes (Childs and Flint, 1987;Groot et al, 1997;Man and Lieffers, 1999), which can cause poor or failed regeneration of some shade-tolerant conifers such as white spruce (Picea glauca (Moench) Voss) (Mullin, 1963;Grossnickle, 1988;Lieffers, 1997, 1999). Sufficient overstory canopy can be left to suppress development of www.elsevier.com/locate/foreco Available online at www.sciencedirect.com Forest Ecology and Management 255 (2008) [697][698][699][700][701][702][703][704][705][706] intolerant hardwoods, woody shrubs, grasses, and herbs and yet accommodate the regeneration and reasonable growth of shadetolerant crop trees (Lieffers et al, 1993Lieffers and Beck, 1994;Prévost and Pothier, 2003), effectively reducing herbicide use and reforestation cost (MacDonald et al, 2004). In northern Ontario, boreal mixedwood stands often develop an abundant advance regeneration (Popadiouk et al, 2004) that is sufficient for the next crop.…”

“…In northern Ontario, boreal mixedwood stands often develop an abundant advance regeneration (Popadiouk et al, 2004) that is sufficient for the next crop. Protecting this well-established advance growth shortens rotation time and reduces cost associated with regeneration and stand tending (Bergeron and Harvey, 1997;MacDonald et al, 2004).…”

“…To test the feasibility of enhancing conifers through partial cutting and protection of advance regeneration, a trial was set up in 1994 in northeastern Ontario (MacDonald et al, 2004). The 5-year responses of light conditions, understory shrubs, and hardwood and conifer regeneration were reported by MacDonald et al (2004).…”

Influence of Mature Overstory Trees on Adjacent 12-Year Regeneration and the Woody Understory: Aggregated Retention versus Intact Forest

“…Aggregates had a negative influence on seedling cover up to 5 m into regenerating harvest areas, but negative correlations between seedling cover and multiple measures of shrub abundance suggest this could have been an indirect effect resulting from the level of competition exerted by shrubs which were relatively high in density, biomass, and cover near the harvested side of those edges ( Figure 3). As observed in boreal aspen-mixed woods [35], retention did not appear to reduce competition from shrubs in nearby harvested areas. In fact, interpretation of the lesser difference between observed plots and reference (open, harvested) plots near aggregates along Axis 3 (positively correlated with small shrub abundance) suggests the possibility that aggregates had a lower negative influence on shrubs than intact forest.…”