Sugar maple and yellow birch regeneration in response to canopy opening, liming and vegetation control in a temperate deciduous forest of Quebec

Abstract

a b s t r a c tWe examined how the density, growth and survival of sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britton) regeneration are influenced by gap size, soil nutrient availability and understory vegetation. We used a factorial combination of (1) three gap sizes (small: <100 m 2 ; medium: 100-300 m 2 ; large: ∼1000 m 2 ); (2) presence/absence of liming (92% CaCO 3 at 500 kg ha −1 , 1st year postharvest); and (3) presence/absence of vegetation control (weeding twice a year; 1st to 3rd year postharvest). We monitored height increment and survival of 1500 seedlings and saplings of both species from the 3rd to the 6th year post-harvest, and assessed density 6 years post-harvest. Both species exhibited a complex set of density, growth and survival responses across the combination of treatments. Compared to sugar maple, yellow birch had an overall lower density, greater growth, and similar survival rate; the two species attained maximum values in different gap size for density, and similar gap size for growth and survival. Liming had very little or no effect on the species. The growth of yellow birch was slightly but significantly greater when understory vegetation was controlled, particularly in medium and large gaps. These results suggest that a variety of canopy gap sizes can provide the right combination of understory conditions for regenerating these two functionally different tree species.

Regeneration Responses to Management for Old-Growth Characteristics in Northern Hardwood-Conifer Forests

“…Sugar maple typically has faster growth rates than beech under higher light conditions in gaps (e.g., [64][65][66]). However, due to asexual reproduction through root sprouting and shared belowground nutritional supply, beech can often outcompete sugar maple in the understory, ultimately overtopping sexually reproduced maple [67][68][69]. In addition to outcompeting sugar maple, beech produces abundant beech leaf litter which contains leachate with phytotoxins that inhibit the development of sugar maple seedlings [70].…”

Forest vegetation management under debate: an introduction

“…Interestingly, in this study, Picea glauca seedlings responded to vegetation control on clearcuts by increasing seedling diameter but not height, whereas in shelterwood treatments, vegetation control increased both diameter and height growth. Gasser et al (2010) investigated the effect of vegetation control, liming and gap size on the growth Acer saccharum and Betula alleghaniensis. They concluded that, although vegetation control had a significant effect on light and nutrient availability, particularly in large gaps, and resulted in some gain in growth, the high survival rates meant vegetation control was not warranted.…”

Scarification and gap size have interacting effects on northern temperate seedling establishment

“…While limited to just two species (hemlock and paper birch), and only statistically significant for paper birch, this finding suggests that competition from non-tree vegetation can influence seeding layer composition even at the earliest stages of seedling development. In our opinion, the insignificant response of yellow birch, white pine, and hemlock to clipping was likely due to their greater shade tolerance and the short duration of this experiment, rather than an indicator of the potential influence of non-tree vegetation over seedling layer composition, as previous work has shown non-tree vegetation to have negative effects on each species' survival (George and Bazzaz, 1999;Saunders and Puettmann, 1999;Gasser et al, 2010;Kern et al, 2012).…”

“…This paradigm is based on the assumption that the lower light environments produced in smaller harvest gaps favor the establishment of shade tolerant species, while the higher light environments of larger harvest gaps promote the establishment of mid to shade intolerant species (Ricklefs, 1977;Denslow, 1980;McClure et al, 2000;Webster and Lorimer, 2005;Kneeshaw and Prèvost, 2007). Nevertheless, recent evidence from gap regeneration studies suggests that gap dynamics are far less predictable, and may be influenced by several factors in addition to gap size (Shields et al, 2007;Falk et al, 2010;Gasser et al, 2010;Bolton and D'Amato, 2011;Matonis et al, 2011;Kern et al, 2012Kern et al, , 2013Fahey and Lorimer, 2013;Klingsporn-Poznanovic et al, 2013). Consequently, management that manipulates gap size alone to regenerate a more diverse seedling cohort will likely fail.…”