Kobra Maleki, Benoit Lafleur, Brian Harvey, Marc Mazerolle, Nicole J. Fenton. Changes in Deadwood and Understory Vegetation
12 Years after Partial and Clearcut Harvesting in
Mixedwood Stands of Western Quebec, Canada. 2020. Forest Science 66(3):337-350
DOI : 10.1093/forsci/fxz087
Marc Mazerolle, Benoit Lafleur, Brian Harvey. Partial cutting in mixedwood stands: Effects of treatment configuration and intensity on stand structure, regeneration, and tree mortality. 2018. Journal of Sustainable Forestry 38(3):275-291
DOI : 10.1080/10549811.2018.1546597
In temperate and boreal mixedwood forests of eastern North America, partial disturbances such as insect outbreaks and gap dynamics result in the development of irregular forest structures. From a forest ecosystem management perspective, management of these forests should therefore include silvicultural regimes that incorporate medium- to high-retention harvesting. We present 12-year results of a field experiment undertaken to evaluate the effects of variable retention harvesting on stand structure, recruitment, and mortality. Treatments were gap harvesting (GAP), diameter-limit harvesting (DL), careful logging (CL), and careful logging followed by scarification (CL + SCAR), and an unharvested control. Although post-harvest basal area in the GAP treatment was significantly lower than that of controls, it maintained a diameter distribution profile and densities of balsam fir regeneration similar to those of pre-harvest conditions. Lower retention treatments (DL, CL, and CL + SCAR) tended to favor regeneration of pioneer, shade-intolerant species. Except for black spruce (for which mortality was highest in DL), stem mortality was similar among harvesting treatments. From an ecosystem management perspective, this study suggests that gap harvesting can maintain, in the short term, forest stand composition and structure similar to unharvested forests, and could be used where management objectives include the maintenance of late successional forest conditions.
Jessica Smith, Brian Harvey, Marc Mazerolle, Ahmed Koubaa. Sprucing up the mixedwoods: Growth response of white spruce (Picea glauca) to partial cutting in the eastern Canadian boreal forest. 2016. Can. J. For. Res. 46(10):1205-1215
DOI : 10.1139/cjfr-2015-0489
Mixed species stands present a number of opportunities and challenges to forest managers. Boreal mixedwood stands in eastern Canada are often characterized by a canopy of shade intolerant aspen (Populus tremuloides) with more shade tolerant conifers in the sub-canopy layers. Because the aspen and conifers often attain optimal merchantable sizes at different moments, there is an interest in developing silvicultural practices toremoval of aspen and favour accelerated growth of residual conifers. We tested three partial harvesting treatments in mixed aspen - white spruce (Picea glauca) stands in which different proportions of aspen (0, 50, 65 and 100% basal area) were removed. Ten years after treatments, 72 spruce stems destructively sampled for stem analysis. Using linear mixed effect models, we analyzed growth as a function of treatment intensity, time since treatment, social status, pre-treatment growth rate, and neighbourhood competition. Relative to control stands, radial and volume growth responses were detected only in the extreme treatment of 100% aspen removal. In relative terms, suppressed trees showed the greatest magnitude of cumulative growth increase. Growth response was proportional to pre-treatment growth rate and, among neighbouring trees, only coniferous neighbours had a negative effect on white spruce growth.
Arun Bose, Marilou Beaudet, Suzanne Brais, Brian Harvey. Cut with care! 2015. Silviculture Chartered Forester p 18.
Julien Moulinier, Suzanne Brais, Brian Harvey, Ahmed Koubaa. Response of boreal jack pine (Pinus banksiana lamb.) Stands to a gradient of commercial thinning intensities, with and without N fertilization. 2015. Forests 6(8):2678-2702
DOI : 10.3390/f6082678
This study examines tree and stand response to a gradient of commercial thinning intensities and nitrogen fertilization (200 kg N ha?1) in nine jack pine (Pinus banksiana) stands of Eastern Canada over a period of 14 years. Thinning intensity ranged from 0% basal area removal in control plots to 64% in thinned plots. Tree diameter increment, absolute and relative volume increment and mean volume increased with thinning intensity and were higher in fertilized plots. Individual tree response depended on tree diameter, with smallest trees exhibiting highest relative volume increment to thinning intensity. Stand basal area increment was positively associated to initial stand basal area and negatively to stand age. In thinned and fertilized plots, stand volume increment was higher and natural mortality lower than in fertilized only and unfertilized control plots over the 5–14 year period after thinning. However, the positive effect of fertilization on tree volume increment decreased with thinning intensity. Despite positive individual tree growth responses to thinning and fertilization, residual stand volume increment decreased with increased thinning intensity in both fertilized and unfertilized plots. While total cumulative stand volume (harvested + residual) also decreased with thinning intensity in unfertilized plots, comparable total volumes were observed in fertilized + thinned and unthinned control plots. Nitrogen fertilization in the years following commercial thinning enhanced the benefit of thinning on these relatively poor sites by increasing tree diameter growth, lowering mortality, and increasing total stand merchantable volume compared to unfertilized thinned stands.
Arun Bose, Suzanne Brais, Brian Harvey. Does partial harvesting promote old-growth attributes of boreal mixedwood trembling aspen (Populus tremuloides Michx.) stands? 2015. For. Ecol. Manage. 153:173-186
DOI : 10.1016/j.foreco.2015.05.024
In the current context of forest ecosystem management, partial harvesting has been proposed as a silvicultural tool to augment forest variability on managed landscapes and to accelerate the development of structural and compositional attributes of old-growth/late successional stands. The aims of this paper were to (1) identify and characterize, based on the literature, the structural attributes of old-growth aspen-dominated stands in the North American boreal mixedwood forest, and (2) examine the short-term potential of partial harvesting in aspen-dominated stands to accelerate stand development toward these old-growth characteristics. Two stand types – pure aspen (93% aspen basal area) and mixed aspen (81% aspen basal area) – were monitored over a 12-year post-treatment period. The scientific literature suggests that compared to pure, even-aged premature or mature stands, old-growth aspen stands have lower merchantable stem densities and basal area, more large aspen stems, higher stem size variability, more than one cohort of trees, greater percentage area occupied by gaps, higher expanded gap area, and more and larger snags and downed wood. In addition, old-growth aspen mixedwoods characteristically have more shade-tolerant conifers in understory and overstory layers than younger, mature stands. Results of this study indicate that light thinning from below (33% basal area removal) applied in pure aspen stands successfully retained most of the structural attributes of mature aspen stands, but did not generally “accelerate succession” toward old-growth traits in the 12-year time interval since treatment. A dispersed free thinning (45% basal area removal in all merchantable size classes) applied in mixed aspen stands showed its potential to “accelerate succession” by creating canopy gaps similar to old-growth aspen stands and by promoting recruitment of both tolerant and intolerant tree species. Two high intensity partial harvesting treatments, a thinning from above of 61% basal area in pure aspen stands and 400 m2 gap cuts (54% basal area removal) in mixed aspen stands may set back stand development by disproportionally favoring recruitment and growth of intolerant hardwood species.
Klaus Puettmann, Scott McG Wilson, Susan Baker, Pablo J Donoso, Lars Drössler, Girma Amente, Thomas Knoke, Yuanchang Lu, Susanna Nocentini, Francis E Putz, Toshiya Yoshida, Jürgen Bauhus, Brian Harvey. Silvicultural alternatives to conventional even-aged forest management - what limits global adoption? 2015. Forest Ecosystems online
DOI : 10.1186/s40663-015-0031-x
The development of forestry as a scientific and management discipline over the last two centuries has mainly emphasized intensive management operations focused on increased commodity production, mostly wood. This “conventional” forest management approach has typically favored production of even-aged, single-species stands. While alternative management regimes have generally received less attention, this has been changing over the last three decades, especially in countries with developed economies. Reasons for this change include a combination of new information and concerns about the ecological consequences of intensive forestry practices and a willingness on the part of many forest owners and society to embrace a wider set of management objectives. Alternative silvicultural approaches are characterized by a set of fundamental principles, including avoidance of clearcutting, an emphasis on structural diversity and small-scale variability, deployment of mixed species with natural regeneration, and avoidance of intensive site-preparation methods.
Our compilation of the authors’ experiences and perspectives from various parts of the world aims to initiate a larger discussion concerning the constraints to and the potential of adopting alternative silvicultural practices.
The results suggest that a wider adoption of alternative silvicultural practices is currently hindered by a suite of ecological, economic, logistical, informational, cultural, and historical constraints. Individual contexts display their own unique combinations and relative significance of these constraints, and accordingly, targeted efforts, such as regulations and incentives, may help to overcome specific challenges.
In a broader context, we propose that less emphases on strict applications of principles and on stand structures might provide additional flexibility and facilitate the adoption of alternative silvicultural regimes in a broader set of circumstances. At the same time, the acceptance of alternative silvicultural systems as the “preferred or default mode of management” will necessitate and benefit from the continued development of the scientific basis and valuation of a variety of ecosystem goods and services. This publication is aimed to further the discussion in this context.
Yves Bergeron, David Coates, Arun Bose, Suzanne Brais, Brian Harvey. Modelling stand development after partial harvesting in boreal mixedwoods of eastern Canada. 2015. Ecological Modelling 300:123-136
DOI : 10.1016/j.ecolmodel.2015.01.002
Multi-cohort-based forest management has been proposed as a strategy to conciliate wood supply and biodiversity conservation objectives. At the stand-level, the approach involves using partial harvesting to generate structurally complex stands, notably in terms of tree age, size and species mixtures, conditions that are not easily integrated into yield tables. Using SORTIE-ND, a spatially explicit stand dynamics model, we simulated 100-year development patterns following different partial harvesting treatments in two trembling aspen (Populus tremuloides Michx)-dominated stands in eastern Canada, one 76-year old (pure aspen) and the other 90 years old (mixed aspen). The two stand types differed primarily in the nature of their understory: pure aspen stands had little advance conifer growth and a dense understory of a woody shrub species whereas mixed aspen stands were characterized by a dense regeneration layer of shade-tolerant conifers. To do this, we first evaluated model performance using short (12 years) and long (168 years) term empirical data. We then modelled stand dynamics following a range of simulated partial harvesting treatments of different intensities (33, 61 and 80% basal area removal), and gap sizes (400, 900 and 1600 m2). Following mortality of the first cohort of aspen, simulations projected dominance of conifer species, white spruce in particular, in unharvested controls of pure aspen stands and balsam fir in mixed aspen stands. Aspen recruitment increased with intensity of partial harvesting. All gap treatments and the 80% dispersed harvesting favored recruitment of aspen over conifer species. After 100-year simulation runs, the 1600 m2 gap treatment resulted in highest stand basal areas, 38.0 and 34.1 m2 ha?1, of which 18% and 28% consisted of intermediate- to shade-tolerant conifer species in pure aspen stands and in mixed aspen stands, respectively. Concerns surrounding partial harvesting have tended to focus on absolute retention levels and standing residence times of trees; however, our results demonstrate that both stand structure and timber production rates are influenced not only by retention levels after partial harvesting but also by spatial configuration of the residual trees. We identified several model functions that are likely responsible for divergences between empirical conditions and those simulated by SORTIE-ND for the boreal mixedwood and suggest specific empirical studies to improve parameter functions of this modelling tool.
Arun Bose, Suzanne Brais, Brian Harvey. Sapling recruitment and mortality dynamics following partial harvesting in aspen-dominated mixedwoods in eastern Canada. 2014. For. Ecol. Manage. 329:37-48
DOI : 10.1016/j.foreco.2014.06.004
Boreal mixedwood management has shifted from a relatively narrow focus on commercial wood supply to greater consideration of the natural dynamics and multiple ecological services. This recognition has generated interest in ecosystem management approaches that include diversifying and adapting silvicultural practices, including partial harvesting. The effects of partial harvesting on stand dynamics was assessed over a 12-year period in trembling aspen (Populus tremuloides Michx.) dominated stands in northwestern Quebec, Canada. Four treatments were tested: clearcuts (100% basal area (BA) removal); 1/3 partial cut (1/3 PC, 33% BA removal using low thin); 2/3 partial cut (2/3 PC, 61% BA removal using high thin) and controls (0% removal). Aspen sapling recruitment was directly affected by harvesting intensity with 1/3 and 2/3 partial cuts generating 5% and 56%, respectively, of aspen sapling densities in clearcuts. Aspen sapling recruitment increased continuously following clearcut and partial cut treatments with no significant mortality in the sapling layer over the 12-year period. Recruitment of conifer saplings also increased with time and was significantly higher in the two partial cuts than in the clearcut treatment. Twelve years after treatments, mortality of residual aspen stems (?10 cm DBH) reached 250 stems ha?1 12 yr?1 in controls, compared to 106, and 170 stems ha?1 12 yr?1 in 1/3 PC, and 2/3 PC stands, respectively. Initially (1–3 years after treatments), higher overstory aspen mortality was associated with the 2/3 PC treatment. Aspen mortality was strongly associated with small-sized merchantable stems (10–19.9 cm DBH) regardless of treatment. Both partial harvesting treatments had the effect of maintaining mountain maple (Acer spicatum Lamb.), a shade-tolerant, high woody shrub, at densities similar to those in control stands whereas recruitment of mountain maple saplings was negligible in clearcuts due to high aspen recruitment. Our results indicate that (i) heavy-high partial harvesting promotes sapling recruitment of both aspen and conifers when advance regeneration of the latter is present, (ii) because aspen sucker response can be controlled by varying harvesting intensities and stem selection, it is possible to create a range of mixedwood conditions, depending on whether mixed, structurally complex or more regular aspen-dominated stands are desired, and (iii) on rich mixedwood sites, tall woody shrubs could hinder desirable partial harvesting outcomes.
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Arun Bose, Suzanne Brais, Brian Harvey. Trembling aspen (Populus tremuloides Michx.) volume growth in the boreal mixedwood: Effect of partial harvesting, tree social status, and neighborhood competition. 2014. For. Ecol. Manage. 327-209-220
DOI : 10.1016/j.foreco.2014.05.003
Variable retention harvesting, with a focus on maintaining biological legacies on managed landscapes, has been practised in the trembling aspen (Populus tremuloides Michx.) dominated boreal mixedwood forests for about two decades. However, little attention has actually been given to the growth response of aspen to partial harvesting. This is the first study to report on tree-level volume growth response of aspen after partial or variable retention harvesting in the Canadian boreal forest. During the winter of 1998–1999, an uncut control, clearcut and two partial harvesting treatments – 1/3 partial cut (1/3PC, 33% BA removal using low thin); 2/3 partial cut (2/3PC, 61% BA removal using high thin) – were applied in 75 year old aspen-dominated mixedwood stands in a complete randomized block design. Twelve years after treatment application, 27 dominant and 27 co-dominant trees were collected from unharvested controls and the two partial cut treatments for stem analysis. Annual volume increment (AVI) of individual stems was analyzed as a function of treatment, tree social status, pre-treatment growth, time since treatment application (1–12 years) and neighborhood competition. The latter was estimated using a variety of neighborhood competition indices (NCI). There was no evidence of initial growth stagnation after partial harvesting applications. Only the most severe treatment of partial harvesting (2/3 PC) resulted in an increase in volume increment relative to trees in control stands. Annual increase in volume in the 2/3 partial cut was 25.6% higher than controls over 12 years. AVI of dominant trees was higher by 16.2 dm3 yr?1 than that of co-dominants and was proportional to pre-treatment volume growth. No interaction between treatment and social status or pre-treatment growth was observed. The overall results indicate that competition for resources in these stands is essentially size symmetrical. These results should contribute to the development of silviculture prescriptions that aim to maintain both stand productivity and biological legacies.
Freddy Nguema Allogo, Benoit Lafleur, Brian Harvey. Affiche 3
Influence des facteurs biophysiques sur la régénération naturelle après coupe partielle en forêt boréale mixte 19e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Ste-Germaine-Boulé, Québec. (2017-11-30)
Benoit Lafleur, Brian Harvey. Coupe partielle en forêt boréale mixte : Effets sur les débris ligneux et réponse des communautés végétales de sous-bois à un gradient d’intensité de récolte 18e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2016-12-01)
Brian Harvey Coupe partielle dans les peuplements boréaux à dominance de tremble : vers une perspective pancanadienne Midi-foresterie (2015-12-15)
Carine Côté-Germain, Pierre Drapeau, Brian Harvey. La structure du bois mort dans les habitats résiduels de la forêt boréale mixte et résineuse 17e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2015-12-02)
Zahia Ait-Si-Said, Wassim Kharrat, Ahmed Koubaa, Brian Harvey. Variation intra-arbres des propriétés physiques et anatomiques de l’épinette blanche (Picea glauca [MOENCH] VOSS) 17e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2015-12-02)
Osvaldo Valeria, Brian Harvey. Évolution de la composition et de la structure des peuplements issus de feux et de coupe de la forêt boréale mixte du nord-ouest québécois 14e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2012-11-29)
Brian Harvey, Philippe Duval, Suzanne Brais, Annie DesRochers. Éclaircies précommerciales dans le tremble : effets initiaux des traitements conventionnel et à diamètre limite 14e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2012-11-29)
Julie Fradette, Daniel Kneeshaw, Brian Harvey. Effets des conditions microenvironnementales sur la dynamique de régénération de peuplements mixtes 12e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2010-11-13)
Ugo Ouelet-Lapointe, Pierre Drapeau, Brian Harvey. Pic-bois cherchent domicile dans forêt aménagée 11e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2009-12-09)
Benoît Gendreau-Berthiaume, Daniel Kneeshaw, Brian Harvey. Coupes partielles et perturbations naturelles en forêt boréale mixte: Similitudes et différences. Affiche scientifique 11e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2009-12-09)
Brian Harvey Effets à moyen terme de la CPRS sur la régénération naturelle et la végétation compétitrice dans la forêt boréale méridionale. Effets à moyen terme de la CPRS sur la régénératio (2001-11-09)
Brian Harvey SAFE: Sylviculture et aménagement forestier écosystémique dans la Forêt du lac Duparquet. SAFE: Sylviculture et aménagement forestier écosys (2000-03-22)
Brian Harvey Pratiques sylvicoles adaptées : un pas dans la bonne direction. (33 diapos.) 5e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec.
Brian Harvey SAFE-SORTIE: Rencontre du troisième type. (19 diapos.) 4e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec.
Brian Harvey Les sapinières de l’ouest : nouvelles connaissances, nouveau modèle d’aménagement? Colloque sur les nouvelles connaissances de la sapinière 69ième congrès annuel de l’ACFAS. Université Sherbrooke, Sherbrooke, Québec, Canada.
Brian Harvey L’aménagement écosystémique de la pessière abitibienne : Enjeux et avenues de solution. (30 diapos.) 8e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec.
Brian Harvey he Lake Duparquet Research Forest: adapting natural dynamics-based management to the need for increased wood supply in the southern boreal forest of Quebec 3rd International Workshop on 3rd International Workshop on Disturbance dynamics in boreal forests. Kuhmo, Finland.
Brian Harvey Introduction au plan d’aménagement de la Forêt du Lac Duparquet. (20 diapos.) 6e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec.
Suzanne Brais, Brian Harvey. Dynamique après CPRS dans le sud de la forêt boréale 69ième congrès annuel de l’ACFAS. Université Sherbrooke, Sherbrooke, Québec, Canada.
Yvon Grenier, Brian Harvey. Conception et présentation des diagrammes régionaux de gestion de la densité des peuplements de pin gris et d'épinette noire en Abitibi 68ième congrès annuel de l’ACFAS. Université de Montréal, Québec, Canada.