Summary
Published in Forest Ecology and Management 398(Suppl. C): 91-100. https://doi.org/10.1016/j.foreco.2017.04.042
Even-aged systems including clearcutting and its variants have been used for decades in North America for managing conifer-dominated stands with the goal to achieve sustainable wood production. Although clearcutting has been successfully applied in conifer-dominated stands of the boreal forest, it has proved maladapted in the temperate mixedwood forest where hardwood and shrub competition is more intense. Over time, regulated even-aged management has simplified the structure and composition of the temperate mixedwood forest which used to be dominated by late-successional stands with high conifer proportions. This study assesses alternative silvicultural systems inspired by natural dynamics for balsam fir (Abies balsamea [L.] Mill.) – yellow birch (Betula alleghaniensis Britton) stands growing in Québec, Eastern Canada. In absence of stand-replacing disturbances, spruce budworm outbreaks (Choristoneura fumiferana [Clem.]) and windthrow trigger regeneration phases through gap dynamics that result in multi-cohort, irregular stand structures. Here, we assess irregular shelterwood systems aiming at regenerating red spruce (Picea rubens Sarg.), balsam fir and yellow birch. In 2009, we established an experiment made of four randomized blocks comparing a gradient of treatments of increased cutting intensity: (i) uncut control (0% removal, 30m2/ha); (ii) continuous cover irregular shelterwood (19 m2/ha of residual basal area [RBA] at the first cut, 25–30 years intervals without final cut), (iii) extended irregular shelterwood (RBA 17 m2/ha, final cut at year 30), (iv) uniform regular shelterwood (RBA 15 m2/ha, final cut at year 10) and (v) clearcut (harvest of merchantable trees >9 cm DBH). We monitored light transmission, seedbed quality and lower vegetation (<3 m) during the first 5years postcut. Shelterwood treatments diversified both understory light and seedbed conditions, thereby increasing the array of available regeneration niches. Shade-tolerant red spruce and balsam fir established more successfully in the less intense irregular shelterwood treatment (continuous cover) and with a higher spruce: fir proportion. All cutting treatments increased seedling density >30 cm of mid-tolerant yellow birch. Interspecific competition dominated by pin cherry (Prunus pensylvanica L.f.) and red maple (Acer rubrum L.) was the main factor limiting conifer establishment and was more abundant in the clearcut. Maintaining a partial cover in shelterwood treatments successfully limited competition expansion while regenerating target species. Even if relatively short term, results show that irregular shelterwood systems could be a sound alternative to clearcutting for regenerating and maintaining the structure of late-successional balsam fir-yellow birch stands.
Sector(s):
Forests
Categorie(s):
Scientific Article
Theme(s):
Forestry Research, Forests, Silviculture
Departmental author(s):
Author(s)
RAYMOND, Patricia and Steve BÉDARD
Year of publication :
2017
Format :
PDF available upon request
How to get the publication :
ISSN
0378-1127
Keywords :
sylviculture et rendement deaménagement écosystémique, coupe progressive irrégulière, couvert permanent, peuplements mixtes, épinette rouge, sylviculture et rendement des forêts naturelles - peuplements mélangés, Article scientifique de recherche forestière, Picea rubens, silviculture and yield of natural forests - mixed stands, ecosystem-based management, irregular shelterwood, femelschlag, continuous cover forestry, mixedwoods, red spruces forêts naturelles - peuplements mélangés, Article scientifique de recherche forestière, Picea rubens, silviculture and yield of natural forests - mixed stands, ecosystem-based management, irregular shelterwood, femelschlag, continuous cover forestry, mixedwoods, red spruce
