Daniel Dumais - Academia.edu (original) (raw)

Papers by Daniel Dumais

The Forestry Chronicle

Since the mid 1990s, partial cuts have been widely used in yellow birch–conifer stands (BJR, bétu... more Since the mid 1990s, partial cuts have been widely used in yellow birch–conifer stands (BJR, bétulaies jaunes résineuses) in the temperate forests of Québec. We studied the impact of residual basal area on stand composition and on the time required to reconstitute enough merchantable basal area to allow for a second partial cut, according to the usual standards of forest management in Québec. To do so, we used a dataset from 9 experiments as well as simulations of the Artémis-2014 growth model and those of a new model, BJR, which we calibrated using the study data. Our results show that residual basal area influences stand periodic annual increment, which peaks 10 to 15 years after the cut. Residual basal area also influences the length of the cutting cycle and future stand composition. We estimated a mean cutting cycle of 24 years for a mean residual basal area of 18 m2·ha-1, and of 40 years for a mean residual basal area of 14 m2·ha-1. For the latter, our results also show that so...

Canadian Journal of Forest Research, May 1, 2010

We present the effects, 10 years after treatment, of different cutting intensities (removal of 0%... more We present the effects, 10 years after treatment, of different cutting intensities (removal of 0%, 35%, 50%, 65%, and 100% of basal area (BA)) on the response of residual trees in a 60-year-old mixed aspen–conifer stand in Quebec, Canada. While decennial mortality reached 170 stems·ha–1 under natural conditions (control, 24 m2·ha–1 BA), the removal of mature trembling aspen ( Populus tremuloides Michx.) trees reduced hardwood losses to 125, 105, and 0 stems·ha–1, respectively, in the 35%, 50%, and 65% cuttings, without affecting losses of coniferous species (≤25 stems·ha–1). The growth response of conifers was generally higher than that of broad-leaved species. For hardwoods, the decennial gains in merchantable BA decreased with respect to the control (3.2 m2·ha–1), to 1.2 m2·ha–1 in the 35% cut and to 0.9 m2·ha–1 in the 50% cut, but increased under the 65% cut (2.5 m2·ha–1). For conifers, gains were proportional to removal in partial cuts (2.6–4.9 m2·ha–1) and lower in the control (1.7 m2·ha–1). As a whole, our results suggest that partial cutting may be an effective means of increasing growth of the softwood proportion occupying the intermediate and suppressed strata in a mixed aspen-dominated stand.

Scandinavian Journal of Forest Research, Aug 18, 2019

Depletion of white spruce (Picea glauca) in mixedwood forest is a frequent problem, particularly ... more Depletion of white spruce (Picea glauca) in mixedwood forest is a frequent problem, particularly in stands that were high-graded as a result of inadequate silviculture and spruce budworm (Choristoneura fumiferana) epidemics. To provide information that will help guide restoration efforts, we assessed the effect of four seed-tree retention (STR: 0, 10, 40 and 60 trees/ha) levels and two scarification (SC: patch scarification and disk-trenching) types on white spruce reintroduced by planting in a high-graded yellow birch (Betula alleghaniensis)-conifer stand. We present the 9-year results from the seedling physiology, nutrition and morphology. Physiology and nutrition changed with years, but did not vary with STR levels and SC types. Significant increases in the number of internodal branches, height growth, and total height at the two lowest STR levels and after release suggest that the performance of white spruce in terms of morphology and growth is sensitive to small variations in available light. Because seedling morphology and growth were similar between SC types, a moderate disturbance of the forest floor by disk-trenching would be sufficient at a relatively low cost. Our findings highlight that the STR levels influenced the morphology and growth of planted white spruce seedlings more than the SC types.

Forest Ecology and Management, Dec 1, 2020

Multiparty Session Types (MPST) are a well-established typing discipline for messagepassing proce... more Multiparty Session Types (MPST) are a well-established typing discipline for messagepassing processes interacting on sessions involving two or more participants. Session typing can ensure desirable properties: absence of communication errors and deadlocks, and protocol conformance. We propose a novel MPST theory based on a rely/guarantee typing system, that checks (1) the guaranteed behaviour of the process being typed, and (2) the relied upon behaviour of other processes. Crucially, our theory achieves type safety by enforcing a typing context liveness invariant throughout typing derivations. Unlike "classic" MPST works, our typing system does not depend on global session types, and does not use syntactic duality checks. As a result, our new theory can prove type safety for processes that implement protocols with complex inter-role dependencies, thus sidestepping an intrinsic limitation of "classic" MPST.

Ecological Indicators, Dec 1, 2020

This management paradigm presumes that biodiversity and ecosystem functions will be maintained an... more This management paradigm presumes that biodiversity and ecosystem functions will be maintained and, hence, sustainability will be achieved by reducing gaps in the variability of key forest attributes (e.g., species composition, stand structure, dead wood, landscape age structure) between managed and natural forests (Gauthier et al., 2009; Urli et al., 2017). Yet, even if ecosystem management has already been widely implemented, there is still a need for the development of comprehensive and operational assessment approaches that validate its

New Forests, Sep 1, 2018

Advance regeneration of red spruce (Picea rubens Sarg.) is scarce in many forest stands, due to p... more Advance regeneration of red spruce (Picea rubens Sarg.) is scarce in many forest stands, due to past clearcuts and heavy harvesting of large seed trees in partial cuts. Understory enrichment planting has been proposed as a means to reintroduce the species in managed stands in which regeneration is deficient. Here, we present 5-year results regarding survival and growth dynamics of red spruce seedlings planted under hardwood, mixedwood, and coniferous forest covers following various cuts (each made on 0.5-1.2 ha square area): hybrid single-tree and group-selection, irregular shelterwood (two variants: continuous cover and extended irregular shelterwood), uniform regular shelterwood, harvesting with advance regeneration protection (HARP), and careful logging around advanced growth (hereafter referred to as 'patch clearcut'). Five-year seedling survival did not vary among cuts except under the coniferous cover, where it was better in the heavier cuts (HARP and patch clearcut; 67%) than under continuous cover shelterwood cuts (24%), in which browsing occurrence was high (around 80%). Under the hardwood cover, height, diameter and biomass growth were greater in the extended irregular shelterwood cut than in other treatments. Under the mixedwood and coniferous covers, seedling growth was greater in patch clearcut, likely because transmitted light (90-100% full sunlight) was higher than in other cuts (around 30%). Results suggest that red spruce could be reintroduced using enrichment planting under a partial forest cover, but that additional treatments could be necessary to manage light and to limit browsing pressure in order to optimize long-term survival and growth performance.

Tree Physiology, Aug 1, 2008

We investigated ecophysiological and growth responses of short (0.4 to 1.3 m in height) advance r... more We investigated ecophysiological and growth responses of short (0.4 to 1.3 m in height) advance regeneration of red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea L.) six years after removal of 0, 40, 50, 60 and 100% of the overstory basal area (BA) in two yellow birch-conifer stands. Partial cuts significantly increased stomatal conductance of red spruce only. Light-saturated photosynthesis (leafarea basis) of both species increased with BA removal, but unlike red spruce, specific leaf area (SLA) of balsam fir decreased with increased cutting intensity. Partial cuts appreciably increased the concentration of N and Ca in red spruce and balsam fir foliage, respectively, and resulted in decreased foliar concentrations of K in red spruce and Mg in balsam fir. The height and lateral growth of both species increased with BA removal, although partial cuts were more beneficial to balsam fir. The data suggest that short advance regeneration of red spruce and balsam fir can coexist under partial overstory conditions, but balsam fir has physiological characteristics and a capacity for morphological adjustment (SLA) that places it at an advantage when in competition with red spruce.

Tree Physiology, Jan 17, 2014

We examined the ecophysiology and growth of 0.3-1.3 m tall advance red spruce (Picea rubens Sarg.... more We examined the ecophysiology and growth of 0.3-1.3 m tall advance red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea [L.] Mill.) regeneration during a 5-year period following the application of different harvest types producing three sizes of canopy openings: (i) small gaps (<100 m 2 in area; SMA) created by partial uniform single-tree harvest; (ii) irregular gaps of intermediate size (100-300 m 2 ; INT) created by group-selection harvest (removal of groups of trees, mainly balsam fir, with uniform partial removal between groups); and (iii) large circular gaps (700 m 2 ; LAR) created by patch-selection harvest (removal of trees in 30-m diameter circular areas with uniform partial removal between gaps). An unharvested control (CON) was monitored for comparison. At the ecophysiological level, we mainly found differences in light-saturated photosynthesis of red spruce and specific leaf area of balsam fir among treatments. Consequently, we observed good height growth of both species in CON and INT, but fir surpassed spruce in SMA and LAR. Results suggest that intermediate 100-300 m 2 irregular openings create microenvironmental conditions that may promote short-term ecophysiology and growth of red spruce, allowing the species to compete with balsam fir advance regeneration. Finally, results observed for spruce in large 700-m 2 openings confirm its inability to grow as rapidly as fir in comparable open conditions.

Forestry Chronicle, Aug 1, 2005

Trees-structure and Function, May 9, 2016

Key messageAfter release, balsam fir has greater ability than red spruce to rapidly capture avail... more Key messageAfter release, balsam fir has greater ability than red spruce to rapidly capture available light and growing space in a wide range of canopy opening.AbstractA large proportion of yellow birch (Betula alleghaniensis Britt.)—conifer stands feature abundant advance growth of shade-tolerant balsam fir (Abies balsamea [L.] Mill.) and red spruce (Picea rubens Sarg.), on which ecosystem-based regeneration strategies should capitalize. However, the morphological response of advanced regeneration to higher light levels following harvesting has yet to be described. Preferential carbon allocation to apical vs. lateral meristems has a significant implication on post-cut forest dynamics. We assessed the morphological response of balsam fir and red spruce saplings (1.3–4.0 m in height) to different levels of canopy opening (removal of 0, 40, 50, 60 and 100 % of the basal area) in two sites located in the Québec City region, Canada. Five years after cutting, the height growth (HG), lateral shoot growth (LG) and HG/LG ratio of the two conifer species were highest in the 100 % cut, intermediate in the three partial cuts, and lowest in the control. However, balsam fir had a 40 % higher HG and a 60 % higher LG, resulting in an HG/LG ratio 30 % lower than red spruce. At that time, both species increased their LG in the upper part of the crown in cutting treatments, although this shift was less pronounced for spruce in partial cuts. The number of internodal branches increased following canopy opening, while the number of branches per whorl was less impacted. Relationships between light availability and morphological variables were strong (pseudo-R2 = 0.54–0.71) and comparable between the two conifer species. However, balsam fir had higher HG and LG, and produced more internodal branches at all light levels. Fir even responded to higher light levels (60–70 % of full light) than spruce (<60 %). Therefore, results from this study clearly demonstrate that balsam fir has greater ability than red spruce to capture available light and growing space in the short term and in a wide range of canopy opening.

Forest Ecology and Management, Dec 1, 2018

Traditional silvicultural systems such as clearcutting and single-tree selection cutting are crit... more Traditional silvicultural systems such as clearcutting and single-tree selection cutting are critiqued for their tendency to simplify forest complexity. By more closely emulating natural disturbance regimes and increasing the availability and heterogeneity in understory light levels, we pose that systems causing intermediate disturbances such as the single-tree and small group selection cutting system can promote tree regeneration, retain stand structural attributes, and maintain high understory plant diversity in temperate mixedwood stands. To assess this, we implemented a harvest intensity gradient experiment (residual basal area [BA], % removal) consisting of uncut control (26 m 2 /ha, 0%), light (21 m 2 /ha, 20%), moderate (18 m 2 /ha, 31%) and heavy (15 m 2 /ha, 42%) cutting with retention of legacy trees in uneven-aged yellow birch (Betula alleghaniensis Britton) conifer stands. We evaluated the effects on gap size, light transmittance, abundance of living and dead trees, plant diversity, and regeneration of target species (i.e. yellow birch, red spruce [Picea rubens Sarg.] and balsam fir [Abies balsamea L.]), during the 8 years postcut. Moderate and heavy single-tree and small group selection cutting treatments triggered changes in microenvironments and in understory plant community. Moderate and heavy selection had greater yellow birch seedling density > 30 cm in height compared to the control. Cutting treatments did not significantly improve red spruce and balsam fir regeneration, despite favorable micro-environmental conditions (e.g. gaps averaging 200-350 m 2 and 15-40% transmitted light). The vascular plant community rebounded quickly after disturbance and harvesting did not depress any diversity metric or alter community composition beyond control levels. Tree species richness increased in moderate and heavy selection cuts, while vascular species diversity (H′) was greatest in the heavy selection cut. Observed richness and diversity gains were driven by augmented yellow birch and mountain maple (Acer spicatum Lam.) recruitment into larger classes as well as greater forb, tree, and shrub cover in response to greater cutting intensities. Species richness and diversity were positively correlated with increased light availability, but not with light heterogeneity. Our results show that this hybrid selection cutting system benefits yellow birch recruitment without negatively impacting plant diversity. However, because increasing harvest intensity simultaneously enhanced interfering non-commercial species abundance (e.g. mountain maple), failed to improve red spruce regeneration, and decreased the abundance of large trees (diameter at breast height > 29 cm), we caution to opt for moderate cutting intensity in this forest type. Additional treatments such as enrichment planting in harvest gaps might be necessary to maintain red spruce over time.

Forest Ecology and Management, Oct 1, 2014

We used two-step shelterwood cutting to release conifer advance growth and limit development of t... more We used two-step shelterwood cutting to release conifer advance growth and limit development of trembling aspen (Populus tremuloïdes Michx.) suckers in a stratified mixed aspen-conifer stand, in Quebec, Canada. This study presents the 10-year response of residual trees to the establishment cutting. We examined growth and mortality of merchantable trees (diameter at breast height (DBH) P 9.1 cm) following the application of different cutting intensities (0%, 35%, 50%, 65%, and 100% basal area removal). Initial post-cut densities were 1100, 670, 640, 580 and 150 stems ha À1 , respectively. Mortality of aspen was highest in the uncut control and 35% cut due to senescence, while mortality of paper birch (Betula papyrifera Marsh.) was highest in the 65% cut due to post-logging decadence. In the species mixture under study, the 50% cut allowed for the harvest of declining aspen without excessively opening the canopy that would be detrimental for residual paper birch. Low mortality, high recruitment and a relatively high DBH growth in this moderate cut resulted in a higher 10-year net increment in total basal area (7.0 m 2 ha À1), compared to the 0%, 35%, 65%, and 100% cuts (2.6-3.7 m 2 ha À1). This result was mostly attributable to balsam fir (Abies balsamea (L.) Mill.) that generated two-thirds of the net increment. Therefore, our growth results support retention of small merchantable conifer stems (DBH 9.1-15.0 cm) as a basic strategy to limit hardwood invasion.

Canadian Journal of Forest Research, Apr 1, 2002

The effects of induced root freezing injury on 2+0 white spruce (Picea glauca (Moench) Voss), bla... more The effects of induced root freezing injury on 2+0 white spruce (Picea glauca (Moench) Voss), black spruce (Picea mariana (Mill.) BSP), and jack pine (Pinus banksiana Lamb.) seedlings were studied. Hardened seedlings were exposed to freezing during the fall and cold stored until planting. Seedlings were planted in spring on two field sites with different soil moisture levels (wet or dry). Seedling morphology and physiology were measured periodically during the first growing season, and mortality was evaluated at the end of the season. With the exception of June measurements on the wet site, where daytime water potential fell as low as-2.0 MPa, root damage did not seriously affect shoot water potential. Generally, stomatal conductance decreased with increasing root damage. Net photosynthesis on both sites decreased between 22 and 39% with increasing root damage. Root damage did not affect the ratio of intercellular to ambient CO 2 concentration. As well, reductions in the nitrogen concentration of current-year foliage with increasing root damage were observed, suggesting that the observed reductions in net photosynthesis were caused by nonstomatal factors. Root growth was greater on the wet site than on the dry site, particularly between August and October, when mean soil minimum temperatures were lower on the dry site. On both sites, aerial dry mass was only slightly affected by root damage in July and August, but the effect of damage became more pronounced in October on the wet site. Black spruce and white spruce seedling mortality began being affected when approximately 50% of the root systems were damaged, while jack pine mortality was affected starting at 40% damage. Root damage levels of 50% caused 2.0 and 1.5 cm reductions in annual height increment of white spruce and black spruce, respectively, and 40% damage caused a reduction of 1.0 cm in annual height increment of jack pine. Résumé : Les effets des dommages racinaires causés par le gel ont été étudiés chez des semis 2+0 d'épinette blanche (Picea glauca (Moench) Voss), d'épinette noire (Picea mariana (Mill.) BSP) et de pin gris (Pinus banksiana Lamb.). Des semis endurcis ont été exposés au gel durant l'automne avant d'être entreposés en chambre froide. Au printemps suivant, ces semis ont été plantés sur deux sites ayant des teneurs en eau du sol distinctes (mouilleux et sec). La morphologie et la physiologie des semis ont été mesurées périodiquement durant la première saison de croissance. La mortalité a été évaluée à la fin de la saison. À l'exception des mesures prises sur le site mouilleux en juin, où des valeurs de-2,0 MPa ont été observées, les dommages racinaires n'ont pas sérieusement affecté le potentiel hydrique du xylème. Généralement, la conductance stomatique a diminué avec l'augmentation des dommages. Des diminutions de 22 à 39% de la photosynthèse nette ont été observées sur les deux sites avec l'augmentation des dommages. Les dommages aux racines n'ont pas affecté le ratio de la concentration intercellulaire en CO 2 sur la concentration ambiante en CO 2 , mais des réductions de la teneur en azote du feuillage de l'année courante ont été observées, indiquant que les diminutions de la photosynthèse nette ont été causées par des facteurs non-stomatiques. La croissance racinaire a été plus élevée sur le site mouilleux, particulièrement entre août et octobre alors que les températures minimales moyennes du sol ont été plus basses sur le site sec. Sur les deux sites, l'effet des dommages racinaires sur la biomasse aérienne a été léger en juillet et en août, mais s'est accentué en octobre sur le site mouilleux. Pour l'épinette noire et l'épinette blanche, la mortalité a été perceptible lorsque environ 50% du système racinaire était endommagé. Pour le pin gris, la mortalité a été perceptible à partir de 40% de dommages. Des dommages racinaires de 50% ont causé des réductions de croissance en hauteur de 2,0 et 1,5 cm respectivement pour l'épinette blanche et l'épinette noire. Pour le pin gris, des dommages racinaires de 40% ont provoqué une réduction de croissance en hauteur de 1,0 cm. Dumais et al.

Canadian Journal of Forest Research, Nov 1, 2003

La coupe avec protection de la régénération et des sols (CPRS) et la plantation à la suite d'une ... more La coupe avec protection de la régénération et des sols (CPRS) et la plantation à la suite d'une préparation de terrain ou non (regarni) sont largement appliquées pour régénérer les peuplements d'épinette noire (Picea mariana (Mill.) BSP) de la forêt boréale du Québec, Canada. Toutefois, peu d'études à moyen terme ont comparé ces différents modes de régénération. Dans cette étude, nous avons suivi pendant 10 ans la croissance en hauteur et le statut nutritif de marcottes, de semis naturels et de semis plantés d'épinette noire, dans un dispositif expérimental combinant la CPRS, l'ensemencement naturel, la plantation et deux types de scarifiage (cônes et disques). En l'absence de scarifiage, la croissance des semis plantés (5,8 cm•an-1) a été légèrement supérieure à celle des marcottes (4,4 cm•an-1) et des semis naturels (4,1 cm•an-1). Le scarifiage a amélioré la croissance des trois types de régénération, mais le traitement a été plus profitable aux semis plantés (+7,1 cm•an-1) qu'aux semis naturels (+1,6 cm•an-1) et aux marcottes (+1,0 cm•an-1). Cinq ans après le traitement, le scarifiage avait augmenté la concentration en N des aiguilles de l'année courante chez les trois types de régénération, mais cet effet bénéfique n'était plus détectable que chez les marcottes après 10 ans. L'effet du traitement a été variable pour les teneurs en P et K, pour lesquelles la régénération naturelle semble avoir plus profité que les plants. Nos résultats indiquent que le scarifiage est un moyen d'améliorer la croissance initiale et le statut nutritif de la régénération naturelle et artificielle d'épinette noire, afin d'accélérer la remise en production des stations de la forêt boréale soumises à la coupe. De plus, le regarni effectué sans préparation de terrain est apparu nettement moins efficace que la plantation combinée au scarifiage.

Forestry Chronicle, May 1, 2007

The physiological and ecological characteristics of red spruce (Picea rubens Sarg.) are reviewed ... more The physiological and ecological characteristics of red spruce (Picea rubens Sarg.) are reviewed and integrated into ecosystem management options. Red spruce is a shade-tolerant, late-successional conifer species found in the temperate forests of northeastern North America. Its wood, being of excellent quality, is prized by the forest industry. Unfortunately, this high-value species has been in decline throughout its entire range for the past 50 years. At high elevations, in northeastern United States, crown dieback caused by the combined effect of atmospheric pollution and climate is largely responsible of this decline. In other areas, such as Québec (Canada), the scarcity of red spruce is mainly caused by forest management practices that are poorly adapted to the species' ecophysiology. Many physiological studies have shown that the species is sensitive to full sunlight (at juvenile and advance growth stages), high temperatures and frost. It also has particular microsite requirements for seed germination and early seedling establishment, such as the presence of large decaying woody debris. Hence, a management strategy adapted for red spruce should favour the use of partial cutting, maintaining some overstory and dead wood. This will emulate the natural dynamics of small canopy gaps and minimize the physiological stresses to regeneration. The ecophysiological aspects of natural and artificial regeneration of red spruce should be examined with respect to the increased use of partial cutting techniques.

European Journal of Forest Research, Jun 6, 2022

Clear-cutting is one of the most widespread forestry practices used in boreal forests. Clear-cutt... more Clear-cutting is one of the most widespread forestry practices used in boreal forests. Clear-cutting of boreal forests in late successional stages could trigger reversion of successional trajectories back toward forests of earlier stages. Such successional setbacks could generate sustainability issues by prolonging the expected time to compositional recovery after clear-cutting. This could lead to overestimation of allowable cuts of economically important late-successional species if the occurrence of successional setbacks remains unassessed. Our objective was to assess whether clear-cutting without additional regeneration treatments has triggered successional setbacks. We studied postclearcut successional trajectories by using forest inventory data in post-clearcut stands, in light of conceptual successional dynamics models. These data covered the actively managed boreal forest region of Quebec, eastern Canada, which is classified into two ecological regions, themselves subdivided into eastern (cool-wet) and western (warmdry) sub regions. Clear-cutting triggered successional setbacks in half of these regions. Such setbacks could prolong, by at least an additional century, the expected time to compositional recovery after clear-cutting. To prevent the overestimation of allowable cuts of economically important late-successional species, foresters could monitor postclear-cut successional trajectories to assess if setbacks were triggered. Post-clear-cut successional setbacks occurred in the two western ecological regions where climatic conditions are warmer and drier than in their eastern counterpart where no setbacks occurred. Hence, sustainability issues brought on by successional setbacks may be exacerbated by climate change. Finally, furthering our understanding of the 3 transformation of successional dynamics by anthropogenic disturbances will be essential to insure sustainable forestry practices.

Scandinavian Journal of Forest Research, Feb 6, 2018

Careful logging around advance growth and tree planting following site preparation or not (fill p... more Careful logging around advance growth and tree planting following site preparation or not (fill planting) have been widely used to regenerate black spruce (Picea mariana) stands in the boreal forest of Canada. An experiment was established in 1990 to compare these regeneration modes and natural seeding over a 25-year period following two types of scarification (cone-or disktrenching) that were applied at two intensities (single-or double-pass). Without scarification, the three types of regeneration had slow height growth during the first 10 years (3.4-5.8 cm/year). Thereafter, planted seedlings (6.1-9.8 cm/year) and pre-established layers (5.8-8.5 cm/year) had 2-3 times higher growth than natural seedlings (2.6-3.1 cm/year). Scarification improved height growth of the three types of regeneration, but planted seedlings responded much earlier, and more strongly over the 25 years (+9.4 cm/year) than layers (+2.8 cm/year) and natural seedlings (+2.7 cm/year). A shift in the proportion of layers and natural seedlings was observed following treatment. Long-term monitoring revealed that double-pass scarification was beneficial to layer growth from years 15-20, while no positive effect was observed on natural or planted seedlings. Our results suggest that decades may be required for natural regeneration to respond to scarification in cold soils of the boreal forest.

Forestry Chronicle, Mar 30, 2023

Depuis le milieu des années 1990, des coupes partielles sont utilisées de manière généralisée dan... more Depuis le milieu des années 1990, des coupes partielles sont utilisées de manière généralisée dans les bétulaies jaunes résineuses (BJR) de la forêt tempérée du Québec. Nous avons étudié l'effet de la surface terrière résiduelle sur la composition du peuplement et sur le temps nécessaire pour reconstituer une surface terrière marchande permettant généralement de réaliser une seconde coupe partielle selon les standards habituels de l'aménagement forestier au Québec. Pour ce faire, nous avons utilisé un jeu de données rassemblant 9 dispositifs expérimentaux ainsi que les simulations du modèle de croissance Artémis-2014 et d'un nouveau modèle, le modèle BJR, que nous avons étalonné à l'aide des données de l'étude. Nos résultats montrent que la surface terrière résiduelle influence l'accroissement annuel périodique des peuplements, lequel est maximal de 10 à 15 ans après la coupe. La surface terrière résiduelle influence aussi le temps de rotation et la composition du peuplement futur. Nous avons estimé un temps de rotation moyen de 24 ans pour une surface terrière résiduelle moyenne de 18 m 2 •ha-1 , puis de 40 ans pour une surface terrière résiduelle moyenne de 14 m 2 •ha-1. Pour ce dernier, nos résultats indiquent également que des essences opportunistes de moindre valeur commerciale, comme l'érable rouge, pourraient devenir plus abondantes.

Forest Ecology and Management

The Forestry Chronicle

Depuis le milieu des années 1990, des coupes partielles sont utilisées de manière généralisée dan... more Depuis le milieu des années 1990, des coupes partielles sont utilisées de manière généralisée dans les bétulaies jaunes résineuses (BJR) de la forêt tempérée du Québec. Nous avons étudié l’effet de la surface terrière résiduelle sur la composition du peuplement et sur le temps nécessaire pour reconstituer une surface terrière marchande permettant généralement de réaliser une seconde coupe partielle selon les standards habituels de l’aménagement forestier au Québec. Pour ce faire, nous avons utilisé un jeu de données rassemblant 9 dispositifs expérimentaux ainsi que les simulations du modèle de croissance Artémis-2014 et d’un nouveau modèle, le modèle BJR, que nous avons étalonné à l’aide des données de l’étude. Nos résultats montrent que la surface terrière résiduelle influence l’accroissement annuel périodique des peuplements, lequel est maximal de 10 à 15 ans après la coupe. La surface terrière résiduelle influence aussi le temps de rotation et la composition du peuplement futur. ...

The Forestry Chronicle

Since the mid 1990s, partial cuts have been widely used in yellow birch–conifer stands (BJR, bétu... more Since the mid 1990s, partial cuts have been widely used in yellow birch–conifer stands (BJR, bétulaies jaunes résineuses) in the temperate forests of Québec. We studied the impact of residual basal area on stand composition and on the time required to reconstitute enough merchantable basal area to allow for a second partial cut, according to the usual standards of forest management in Québec. To do so, we used a dataset from 9 experiments as well as simulations of the Artémis-2014 growth model and those of a new model, BJR, which we calibrated using the study data. Our results show that residual basal area influences stand periodic annual increment, which peaks 10 to 15 years after the cut. Residual basal area also influences the length of the cutting cycle and future stand composition. We estimated a mean cutting cycle of 24 years for a mean residual basal area of 18 m2·ha-1, and of 40 years for a mean residual basal area of 14 m2·ha-1. For the latter, our results also show that so...

Canadian Journal of Forest Research, May 1, 2010

We present the effects, 10 years after treatment, of different cutting intensities (removal of 0%... more We present the effects, 10 years after treatment, of different cutting intensities (removal of 0%, 35%, 50%, 65%, and 100% of basal area (BA)) on the response of residual trees in a 60-year-old mixed aspen–conifer stand in Quebec, Canada. While decennial mortality reached 170 stems·ha–1 under natural conditions (control, 24 m2·ha–1 BA), the removal of mature trembling aspen ( Populus tremuloides Michx.) trees reduced hardwood losses to 125, 105, and 0 stems·ha–1, respectively, in the 35%, 50%, and 65% cuttings, without affecting losses of coniferous species (≤25 stems·ha–1). The growth response of conifers was generally higher than that of broad-leaved species. For hardwoods, the decennial gains in merchantable BA decreased with respect to the control (3.2 m2·ha–1), to 1.2 m2·ha–1 in the 35% cut and to 0.9 m2·ha–1 in the 50% cut, but increased under the 65% cut (2.5 m2·ha–1). For conifers, gains were proportional to removal in partial cuts (2.6–4.9 m2·ha–1) and lower in the control (1.7 m2·ha–1). As a whole, our results suggest that partial cutting may be an effective means of increasing growth of the softwood proportion occupying the intermediate and suppressed strata in a mixed aspen-dominated stand.

Scandinavian Journal of Forest Research, Aug 18, 2019

Depletion of white spruce (Picea glauca) in mixedwood forest is a frequent problem, particularly ... more Depletion of white spruce (Picea glauca) in mixedwood forest is a frequent problem, particularly in stands that were high-graded as a result of inadequate silviculture and spruce budworm (Choristoneura fumiferana) epidemics. To provide information that will help guide restoration efforts, we assessed the effect of four seed-tree retention (STR: 0, 10, 40 and 60 trees/ha) levels and two scarification (SC: patch scarification and disk-trenching) types on white spruce reintroduced by planting in a high-graded yellow birch (Betula alleghaniensis)-conifer stand. We present the 9-year results from the seedling physiology, nutrition and morphology. Physiology and nutrition changed with years, but did not vary with STR levels and SC types. Significant increases in the number of internodal branches, height growth, and total height at the two lowest STR levels and after release suggest that the performance of white spruce in terms of morphology and growth is sensitive to small variations in available light. Because seedling morphology and growth were similar between SC types, a moderate disturbance of the forest floor by disk-trenching would be sufficient at a relatively low cost. Our findings highlight that the STR levels influenced the morphology and growth of planted white spruce seedlings more than the SC types.

Forest Ecology and Management, Dec 1, 2020

Multiparty Session Types (MPST) are a well-established typing discipline for messagepassing proce... more Multiparty Session Types (MPST) are a well-established typing discipline for messagepassing processes interacting on sessions involving two or more participants. Session typing can ensure desirable properties: absence of communication errors and deadlocks, and protocol conformance. We propose a novel MPST theory based on a rely/guarantee typing system, that checks (1) the guaranteed behaviour of the process being typed, and (2) the relied upon behaviour of other processes. Crucially, our theory achieves type safety by enforcing a typing context liveness invariant throughout typing derivations. Unlike "classic" MPST works, our typing system does not depend on global session types, and does not use syntactic duality checks. As a result, our new theory can prove type safety for processes that implement protocols with complex inter-role dependencies, thus sidestepping an intrinsic limitation of "classic" MPST.

Ecological Indicators, Dec 1, 2020

This management paradigm presumes that biodiversity and ecosystem functions will be maintained an... more This management paradigm presumes that biodiversity and ecosystem functions will be maintained and, hence, sustainability will be achieved by reducing gaps in the variability of key forest attributes (e.g., species composition, stand structure, dead wood, landscape age structure) between managed and natural forests (Gauthier et al., 2009; Urli et al., 2017). Yet, even if ecosystem management has already been widely implemented, there is still a need for the development of comprehensive and operational assessment approaches that validate its

New Forests, Sep 1, 2018

Advance regeneration of red spruce (Picea rubens Sarg.) is scarce in many forest stands, due to p... more Advance regeneration of red spruce (Picea rubens Sarg.) is scarce in many forest stands, due to past clearcuts and heavy harvesting of large seed trees in partial cuts. Understory enrichment planting has been proposed as a means to reintroduce the species in managed stands in which regeneration is deficient. Here, we present 5-year results regarding survival and growth dynamics of red spruce seedlings planted under hardwood, mixedwood, and coniferous forest covers following various cuts (each made on 0.5-1.2 ha square area): hybrid single-tree and group-selection, irregular shelterwood (two variants: continuous cover and extended irregular shelterwood), uniform regular shelterwood, harvesting with advance regeneration protection (HARP), and careful logging around advanced growth (hereafter referred to as 'patch clearcut'). Five-year seedling survival did not vary among cuts except under the coniferous cover, where it was better in the heavier cuts (HARP and patch clearcut; 67%) than under continuous cover shelterwood cuts (24%), in which browsing occurrence was high (around 80%). Under the hardwood cover, height, diameter and biomass growth were greater in the extended irregular shelterwood cut than in other treatments. Under the mixedwood and coniferous covers, seedling growth was greater in patch clearcut, likely because transmitted light (90-100% full sunlight) was higher than in other cuts (around 30%). Results suggest that red spruce could be reintroduced using enrichment planting under a partial forest cover, but that additional treatments could be necessary to manage light and to limit browsing pressure in order to optimize long-term survival and growth performance.

Tree Physiology, Aug 1, 2008

We investigated ecophysiological and growth responses of short (0.4 to 1.3 m in height) advance r... more We investigated ecophysiological and growth responses of short (0.4 to 1.3 m in height) advance regeneration of red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea L.) six years after removal of 0, 40, 50, 60 and 100% of the overstory basal area (BA) in two yellow birch-conifer stands. Partial cuts significantly increased stomatal conductance of red spruce only. Light-saturated photosynthesis (leafarea basis) of both species increased with BA removal, but unlike red spruce, specific leaf area (SLA) of balsam fir decreased with increased cutting intensity. Partial cuts appreciably increased the concentration of N and Ca in red spruce and balsam fir foliage, respectively, and resulted in decreased foliar concentrations of K in red spruce and Mg in balsam fir. The height and lateral growth of both species increased with BA removal, although partial cuts were more beneficial to balsam fir. The data suggest that short advance regeneration of red spruce and balsam fir can coexist under partial overstory conditions, but balsam fir has physiological characteristics and a capacity for morphological adjustment (SLA) that places it at an advantage when in competition with red spruce.

Tree Physiology, Jan 17, 2014

We examined the ecophysiology and growth of 0.3-1.3 m tall advance red spruce (Picea rubens Sarg.... more We examined the ecophysiology and growth of 0.3-1.3 m tall advance red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea [L.] Mill.) regeneration during a 5-year period following the application of different harvest types producing three sizes of canopy openings: (i) small gaps (<100 m 2 in area; SMA) created by partial uniform single-tree harvest; (ii) irregular gaps of intermediate size (100-300 m 2 ; INT) created by group-selection harvest (removal of groups of trees, mainly balsam fir, with uniform partial removal between groups); and (iii) large circular gaps (700 m 2 ; LAR) created by patch-selection harvest (removal of trees in 30-m diameter circular areas with uniform partial removal between gaps). An unharvested control (CON) was monitored for comparison. At the ecophysiological level, we mainly found differences in light-saturated photosynthesis of red spruce and specific leaf area of balsam fir among treatments. Consequently, we observed good height growth of both species in CON and INT, but fir surpassed spruce in SMA and LAR. Results suggest that intermediate 100-300 m 2 irregular openings create microenvironmental conditions that may promote short-term ecophysiology and growth of red spruce, allowing the species to compete with balsam fir advance regeneration. Finally, results observed for spruce in large 700-m 2 openings confirm its inability to grow as rapidly as fir in comparable open conditions.

Forestry Chronicle, Aug 1, 2005

Trees-structure and Function, May 9, 2016

Key messageAfter release, balsam fir has greater ability than red spruce to rapidly capture avail... more Key messageAfter release, balsam fir has greater ability than red spruce to rapidly capture available light and growing space in a wide range of canopy opening.AbstractA large proportion of yellow birch (Betula alleghaniensis Britt.)—conifer stands feature abundant advance growth of shade-tolerant balsam fir (Abies balsamea [L.] Mill.) and red spruce (Picea rubens Sarg.), on which ecosystem-based regeneration strategies should capitalize. However, the morphological response of advanced regeneration to higher light levels following harvesting has yet to be described. Preferential carbon allocation to apical vs. lateral meristems has a significant implication on post-cut forest dynamics. We assessed the morphological response of balsam fir and red spruce saplings (1.3–4.0 m in height) to different levels of canopy opening (removal of 0, 40, 50, 60 and 100 % of the basal area) in two sites located in the Québec City region, Canada. Five years after cutting, the height growth (HG), lateral shoot growth (LG) and HG/LG ratio of the two conifer species were highest in the 100 % cut, intermediate in the three partial cuts, and lowest in the control. However, balsam fir had a 40 % higher HG and a 60 % higher LG, resulting in an HG/LG ratio 30 % lower than red spruce. At that time, both species increased their LG in the upper part of the crown in cutting treatments, although this shift was less pronounced for spruce in partial cuts. The number of internodal branches increased following canopy opening, while the number of branches per whorl was less impacted. Relationships between light availability and morphological variables were strong (pseudo-R2 = 0.54–0.71) and comparable between the two conifer species. However, balsam fir had higher HG and LG, and produced more internodal branches at all light levels. Fir even responded to higher light levels (60–70 % of full light) than spruce (<60 %). Therefore, results from this study clearly demonstrate that balsam fir has greater ability than red spruce to capture available light and growing space in the short term and in a wide range of canopy opening.

Forest Ecology and Management, Dec 1, 2018

Traditional silvicultural systems such as clearcutting and single-tree selection cutting are crit... more Traditional silvicultural systems such as clearcutting and single-tree selection cutting are critiqued for their tendency to simplify forest complexity. By more closely emulating natural disturbance regimes and increasing the availability and heterogeneity in understory light levels, we pose that systems causing intermediate disturbances such as the single-tree and small group selection cutting system can promote tree regeneration, retain stand structural attributes, and maintain high understory plant diversity in temperate mixedwood stands. To assess this, we implemented a harvest intensity gradient experiment (residual basal area [BA], % removal) consisting of uncut control (26 m 2 /ha, 0%), light (21 m 2 /ha, 20%), moderate (18 m 2 /ha, 31%) and heavy (15 m 2 /ha, 42%) cutting with retention of legacy trees in uneven-aged yellow birch (Betula alleghaniensis Britton) conifer stands. We evaluated the effects on gap size, light transmittance, abundance of living and dead trees, plant diversity, and regeneration of target species (i.e. yellow birch, red spruce [Picea rubens Sarg.] and balsam fir [Abies balsamea L.]), during the 8 years postcut. Moderate and heavy single-tree and small group selection cutting treatments triggered changes in microenvironments and in understory plant community. Moderate and heavy selection had greater yellow birch seedling density > 30 cm in height compared to the control. Cutting treatments did not significantly improve red spruce and balsam fir regeneration, despite favorable micro-environmental conditions (e.g. gaps averaging 200-350 m 2 and 15-40% transmitted light). The vascular plant community rebounded quickly after disturbance and harvesting did not depress any diversity metric or alter community composition beyond control levels. Tree species richness increased in moderate and heavy selection cuts, while vascular species diversity (H′) was greatest in the heavy selection cut. Observed richness and diversity gains were driven by augmented yellow birch and mountain maple (Acer spicatum Lam.) recruitment into larger classes as well as greater forb, tree, and shrub cover in response to greater cutting intensities. Species richness and diversity were positively correlated with increased light availability, but not with light heterogeneity. Our results show that this hybrid selection cutting system benefits yellow birch recruitment without negatively impacting plant diversity. However, because increasing harvest intensity simultaneously enhanced interfering non-commercial species abundance (e.g. mountain maple), failed to improve red spruce regeneration, and decreased the abundance of large trees (diameter at breast height > 29 cm), we caution to opt for moderate cutting intensity in this forest type. Additional treatments such as enrichment planting in harvest gaps might be necessary to maintain red spruce over time.

Forest Ecology and Management, Oct 1, 2014

We used two-step shelterwood cutting to release conifer advance growth and limit development of t... more We used two-step shelterwood cutting to release conifer advance growth and limit development of trembling aspen (Populus tremuloïdes Michx.) suckers in a stratified mixed aspen-conifer stand, in Quebec, Canada. This study presents the 10-year response of residual trees to the establishment cutting. We examined growth and mortality of merchantable trees (diameter at breast height (DBH) P 9.1 cm) following the application of different cutting intensities (0%, 35%, 50%, 65%, and 100% basal area removal). Initial post-cut densities were 1100, 670, 640, 580 and 150 stems ha À1 , respectively. Mortality of aspen was highest in the uncut control and 35% cut due to senescence, while mortality of paper birch (Betula papyrifera Marsh.) was highest in the 65% cut due to post-logging decadence. In the species mixture under study, the 50% cut allowed for the harvest of declining aspen without excessively opening the canopy that would be detrimental for residual paper birch. Low mortality, high recruitment and a relatively high DBH growth in this moderate cut resulted in a higher 10-year net increment in total basal area (7.0 m 2 ha À1), compared to the 0%, 35%, 65%, and 100% cuts (2.6-3.7 m 2 ha À1). This result was mostly attributable to balsam fir (Abies balsamea (L.) Mill.) that generated two-thirds of the net increment. Therefore, our growth results support retention of small merchantable conifer stems (DBH 9.1-15.0 cm) as a basic strategy to limit hardwood invasion.

Canadian Journal of Forest Research, Apr 1, 2002

The effects of induced root freezing injury on 2+0 white spruce (Picea glauca (Moench) Voss), bla... more The effects of induced root freezing injury on 2+0 white spruce (Picea glauca (Moench) Voss), black spruce (Picea mariana (Mill.) BSP), and jack pine (Pinus banksiana Lamb.) seedlings were studied. Hardened seedlings were exposed to freezing during the fall and cold stored until planting. Seedlings were planted in spring on two field sites with different soil moisture levels (wet or dry). Seedling morphology and physiology were measured periodically during the first growing season, and mortality was evaluated at the end of the season. With the exception of June measurements on the wet site, where daytime water potential fell as low as-2.0 MPa, root damage did not seriously affect shoot water potential. Generally, stomatal conductance decreased with increasing root damage. Net photosynthesis on both sites decreased between 22 and 39% with increasing root damage. Root damage did not affect the ratio of intercellular to ambient CO 2 concentration. As well, reductions in the nitrogen concentration of current-year foliage with increasing root damage were observed, suggesting that the observed reductions in net photosynthesis were caused by nonstomatal factors. Root growth was greater on the wet site than on the dry site, particularly between August and October, when mean soil minimum temperatures were lower on the dry site. On both sites, aerial dry mass was only slightly affected by root damage in July and August, but the effect of damage became more pronounced in October on the wet site. Black spruce and white spruce seedling mortality began being affected when approximately 50% of the root systems were damaged, while jack pine mortality was affected starting at 40% damage. Root damage levels of 50% caused 2.0 and 1.5 cm reductions in annual height increment of white spruce and black spruce, respectively, and 40% damage caused a reduction of 1.0 cm in annual height increment of jack pine. Résumé : Les effets des dommages racinaires causés par le gel ont été étudiés chez des semis 2+0 d'épinette blanche (Picea glauca (Moench) Voss), d'épinette noire (Picea mariana (Mill.) BSP) et de pin gris (Pinus banksiana Lamb.). Des semis endurcis ont été exposés au gel durant l'automne avant d'être entreposés en chambre froide. Au printemps suivant, ces semis ont été plantés sur deux sites ayant des teneurs en eau du sol distinctes (mouilleux et sec). La morphologie et la physiologie des semis ont été mesurées périodiquement durant la première saison de croissance. La mortalité a été évaluée à la fin de la saison. À l'exception des mesures prises sur le site mouilleux en juin, où des valeurs de-2,0 MPa ont été observées, les dommages racinaires n'ont pas sérieusement affecté le potentiel hydrique du xylème. Généralement, la conductance stomatique a diminué avec l'augmentation des dommages. Des diminutions de 22 à 39% de la photosynthèse nette ont été observées sur les deux sites avec l'augmentation des dommages. Les dommages aux racines n'ont pas affecté le ratio de la concentration intercellulaire en CO 2 sur la concentration ambiante en CO 2 , mais des réductions de la teneur en azote du feuillage de l'année courante ont été observées, indiquant que les diminutions de la photosynthèse nette ont été causées par des facteurs non-stomatiques. La croissance racinaire a été plus élevée sur le site mouilleux, particulièrement entre août et octobre alors que les températures minimales moyennes du sol ont été plus basses sur le site sec. Sur les deux sites, l'effet des dommages racinaires sur la biomasse aérienne a été léger en juillet et en août, mais s'est accentué en octobre sur le site mouilleux. Pour l'épinette noire et l'épinette blanche, la mortalité a été perceptible lorsque environ 50% du système racinaire était endommagé. Pour le pin gris, la mortalité a été perceptible à partir de 40% de dommages. Des dommages racinaires de 50% ont causé des réductions de croissance en hauteur de 2,0 et 1,5 cm respectivement pour l'épinette blanche et l'épinette noire. Pour le pin gris, des dommages racinaires de 40% ont provoqué une réduction de croissance en hauteur de 1,0 cm. Dumais et al.

Canadian Journal of Forest Research, Nov 1, 2003

La coupe avec protection de la régénération et des sols (CPRS) et la plantation à la suite d'une ... more La coupe avec protection de la régénération et des sols (CPRS) et la plantation à la suite d'une préparation de terrain ou non (regarni) sont largement appliquées pour régénérer les peuplements d'épinette noire (Picea mariana (Mill.) BSP) de la forêt boréale du Québec, Canada. Toutefois, peu d'études à moyen terme ont comparé ces différents modes de régénération. Dans cette étude, nous avons suivi pendant 10 ans la croissance en hauteur et le statut nutritif de marcottes, de semis naturels et de semis plantés d'épinette noire, dans un dispositif expérimental combinant la CPRS, l'ensemencement naturel, la plantation et deux types de scarifiage (cônes et disques). En l'absence de scarifiage, la croissance des semis plantés (5,8 cm•an-1) a été légèrement supérieure à celle des marcottes (4,4 cm•an-1) et des semis naturels (4,1 cm•an-1). Le scarifiage a amélioré la croissance des trois types de régénération, mais le traitement a été plus profitable aux semis plantés (+7,1 cm•an-1) qu'aux semis naturels (+1,6 cm•an-1) et aux marcottes (+1,0 cm•an-1). Cinq ans après le traitement, le scarifiage avait augmenté la concentration en N des aiguilles de l'année courante chez les trois types de régénération, mais cet effet bénéfique n'était plus détectable que chez les marcottes après 10 ans. L'effet du traitement a été variable pour les teneurs en P et K, pour lesquelles la régénération naturelle semble avoir plus profité que les plants. Nos résultats indiquent que le scarifiage est un moyen d'améliorer la croissance initiale et le statut nutritif de la régénération naturelle et artificielle d'épinette noire, afin d'accélérer la remise en production des stations de la forêt boréale soumises à la coupe. De plus, le regarni effectué sans préparation de terrain est apparu nettement moins efficace que la plantation combinée au scarifiage.

Forestry Chronicle, May 1, 2007

The physiological and ecological characteristics of red spruce (Picea rubens Sarg.) are reviewed ... more The physiological and ecological characteristics of red spruce (Picea rubens Sarg.) are reviewed and integrated into ecosystem management options. Red spruce is a shade-tolerant, late-successional conifer species found in the temperate forests of northeastern North America. Its wood, being of excellent quality, is prized by the forest industry. Unfortunately, this high-value species has been in decline throughout its entire range for the past 50 years. At high elevations, in northeastern United States, crown dieback caused by the combined effect of atmospheric pollution and climate is largely responsible of this decline. In other areas, such as Québec (Canada), the scarcity of red spruce is mainly caused by forest management practices that are poorly adapted to the species' ecophysiology. Many physiological studies have shown that the species is sensitive to full sunlight (at juvenile and advance growth stages), high temperatures and frost. It also has particular microsite requirements for seed germination and early seedling establishment, such as the presence of large decaying woody debris. Hence, a management strategy adapted for red spruce should favour the use of partial cutting, maintaining some overstory and dead wood. This will emulate the natural dynamics of small canopy gaps and minimize the physiological stresses to regeneration. The ecophysiological aspects of natural and artificial regeneration of red spruce should be examined with respect to the increased use of partial cutting techniques.

European Journal of Forest Research, Jun 6, 2022

Clear-cutting is one of the most widespread forestry practices used in boreal forests. Clear-cutt... more Clear-cutting is one of the most widespread forestry practices used in boreal forests. Clear-cutting of boreal forests in late successional stages could trigger reversion of successional trajectories back toward forests of earlier stages. Such successional setbacks could generate sustainability issues by prolonging the expected time to compositional recovery after clear-cutting. This could lead to overestimation of allowable cuts of economically important late-successional species if the occurrence of successional setbacks remains unassessed. Our objective was to assess whether clear-cutting without additional regeneration treatments has triggered successional setbacks. We studied postclearcut successional trajectories by using forest inventory data in post-clearcut stands, in light of conceptual successional dynamics models. These data covered the actively managed boreal forest region of Quebec, eastern Canada, which is classified into two ecological regions, themselves subdivided into eastern (cool-wet) and western (warmdry) sub regions. Clear-cutting triggered successional setbacks in half of these regions. Such setbacks could prolong, by at least an additional century, the expected time to compositional recovery after clear-cutting. To prevent the overestimation of allowable cuts of economically important late-successional species, foresters could monitor postclear-cut successional trajectories to assess if setbacks were triggered. Post-clear-cut successional setbacks occurred in the two western ecological regions where climatic conditions are warmer and drier than in their eastern counterpart where no setbacks occurred. Hence, sustainability issues brought on by successional setbacks may be exacerbated by climate change. Finally, furthering our understanding of the 3 transformation of successional dynamics by anthropogenic disturbances will be essential to insure sustainable forestry practices.

Scandinavian Journal of Forest Research, Feb 6, 2018

Careful logging around advance growth and tree planting following site preparation or not (fill p... more Careful logging around advance growth and tree planting following site preparation or not (fill planting) have been widely used to regenerate black spruce (Picea mariana) stands in the boreal forest of Canada. An experiment was established in 1990 to compare these regeneration modes and natural seeding over a 25-year period following two types of scarification (cone-or disktrenching) that were applied at two intensities (single-or double-pass). Without scarification, the three types of regeneration had slow height growth during the first 10 years (3.4-5.8 cm/year). Thereafter, planted seedlings (6.1-9.8 cm/year) and pre-established layers (5.8-8.5 cm/year) had 2-3 times higher growth than natural seedlings (2.6-3.1 cm/year). Scarification improved height growth of the three types of regeneration, but planted seedlings responded much earlier, and more strongly over the 25 years (+9.4 cm/year) than layers (+2.8 cm/year) and natural seedlings (+2.7 cm/year). A shift in the proportion of layers and natural seedlings was observed following treatment. Long-term monitoring revealed that double-pass scarification was beneficial to layer growth from years 15-20, while no positive effect was observed on natural or planted seedlings. Our results suggest that decades may be required for natural regeneration to respond to scarification in cold soils of the boreal forest.

Forestry Chronicle, Mar 30, 2023

Depuis le milieu des années 1990, des coupes partielles sont utilisées de manière généralisée dan... more Depuis le milieu des années 1990, des coupes partielles sont utilisées de manière généralisée dans les bétulaies jaunes résineuses (BJR) de la forêt tempérée du Québec. Nous avons étudié l'effet de la surface terrière résiduelle sur la composition du peuplement et sur le temps nécessaire pour reconstituer une surface terrière marchande permettant généralement de réaliser une seconde coupe partielle selon les standards habituels de l'aménagement forestier au Québec. Pour ce faire, nous avons utilisé un jeu de données rassemblant 9 dispositifs expérimentaux ainsi que les simulations du modèle de croissance Artémis-2014 et d'un nouveau modèle, le modèle BJR, que nous avons étalonné à l'aide des données de l'étude. Nos résultats montrent que la surface terrière résiduelle influence l'accroissement annuel périodique des peuplements, lequel est maximal de 10 à 15 ans après la coupe. La surface terrière résiduelle influence aussi le temps de rotation et la composition du peuplement futur. Nous avons estimé un temps de rotation moyen de 24 ans pour une surface terrière résiduelle moyenne de 18 m 2 •ha-1 , puis de 40 ans pour une surface terrière résiduelle moyenne de 14 m 2 •ha-1. Pour ce dernier, nos résultats indiquent également que des essences opportunistes de moindre valeur commerciale, comme l'érable rouge, pourraient devenir plus abondantes.

Forest Ecology and Management

The Forestry Chronicle

Depuis le milieu des années 1990, des coupes partielles sont utilisées de manière généralisée dan... more Depuis le milieu des années 1990, des coupes partielles sont utilisées de manière généralisée dans les bétulaies jaunes résineuses (BJR) de la forêt tempérée du Québec. Nous avons étudié l’effet de la surface terrière résiduelle sur la composition du peuplement et sur le temps nécessaire pour reconstituer une surface terrière marchande permettant généralement de réaliser une seconde coupe partielle selon les standards habituels de l’aménagement forestier au Québec. Pour ce faire, nous avons utilisé un jeu de données rassemblant 9 dispositifs expérimentaux ainsi que les simulations du modèle de croissance Artémis-2014 et d’un nouveau modèle, le modèle BJR, que nous avons étalonné à l’aide des données de l’étude. Nos résultats montrent que la surface terrière résiduelle influence l’accroissement annuel périodique des peuplements, lequel est maximal de 10 à 15 ans après la coupe. La surface terrière résiduelle influence aussi le temps de rotation et la composition du peuplement futur. ...