Valentina Buttò, Philippe Rozenberg, Annie Deslauriers, Sergio Rossi, Hubert Morin. Environmental and developmental factors driving xylem anatomy and micro-density in black spruce. 2022. New Phytologist 230(3):957-971
DOI : 10.1111/nph.17223
Wood density is the product of carbon allocation for structural growth and reflects the trade-off between mechanical support and water conductivity. We tested a conceptual framework based on the assumption that micro-density depends on direct and indirect relationships with endogenous and exogenous factors. The dynamics of wood formation, including timings and rates of cell division, cell enlargement, and secondary wall deposition, were assessed from microcores collected weekly between 2002 and 2016 from five black spruce stands located along a latitudinal gradient in Quebec, Canada. Cell anatomy and micro-density were recorded by anatomical analyses and X-ray measurements. Our structural equation model explained 80% of micro-density variation within the tree-ring with direct effects of wall thickness (σ = 0.61), cell diameter (σ = −0.51), and photoperiod (σ = −0.26). Wood formation dynamics had an indirect effect on micro-density. Micro-density increased under longer periods of cell-wall deposition and shorter durations of enlargement. Our results fill a critical gap in understanding the relationships underlying micro-density variation in conifers. We demonstrated that short-term responses to environmental variations could be overridden by plastic responses that modulate cell differentiation. Our results point to wood formation dynamics as a reliable predictor of carbon allocation in trees. © 2021 The Authors New Phytologist
Siddhartha Khare, Annie Deslauriers, Hubert Morin, Hooman Latifi, Sergio Rossi. Comparing Time-Lapse PhenoCams with Satellite Observations across the Boreal Forest of Quebec, Canada. 2022. Remote sensing 14(1):100
DOI : 10.3390/rs14010100
Intercomparison of satellite-derived vegetation phenology is scarce in remote locations because of the limited coverage area and low temporal resolution of field observations. By their reliable near-ground observations and high-frequency data collection, PhenoCams can be a robust tool for intercomparison of land surface phenology derived from satellites. This study aims to investigate the transition dates of black spruce (Picea mariana (Mill.) B.S.P.) phenology by comparing fortnightly the MODIS normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI) extracted using the Google Earth Engine (GEE) platform with the daily PhenoCam-based green chromatic coordinate (GCC) index. Data were collected from 2016 to 2019 by PhenoCams installed in six mature stands along a latitudinal gradient of the boreal forests of Quebec, Canada. All time series were fitted by double-logistic functions, and the estimated parameters were compared between NDVI, EVI, and GCC. The onset of GCC occurred in the second week of May, whereas the ending of GCC occurred in the last week of September. We demonstrated that GCC was more correlated with EVI (R2 from 0.66 to 0.85) than NDVI (R2 from 0.52 to 0.68). In addition, the onset and ending of phenology were shown to differ by 3.5 and 5.4 days between EVI and GCC, respectively. Larger differences were detected between NDVI and GCC, 17.05 and 26.89 days for the onset and ending, respectively. EVI showed better estimations of the phenological dates than NDVI. This better performance is explained by the higher spectral sensitivity of EVI for multiple canopy leaf layers due to the presence of an additional blue band and an optimized soil factor value. Our study demonstrates that the phenological observations derived from PhenoCam are comparable with the EVI index. We conclude that EVI is more suitable than NDVI to assess phenology in evergreen species of the northern boreal region, where PhenoCam data are not available. The EVI index could be used as a reliable proxy of GCC for monitoring evergreen species phenology in areas with reduced access, or where repeated data collection from remote areas are logistically difficult due to the extreme weather.
Yaling Zhang, Jian-Guo Huang, Minhuang Wang, Xiaohan Yu, Annie Deslauriers, Patrick Fonti, Eryuan Liang, Harri Mäkinen, Walter Oberhuber, Cyrille B. K. Rathgeber, Roberto Tognetti, Václav Treml, Bao Yang, Lihong Zhai, Jiao-Lin Zhang, Serena Antonucci, Yves Bergeron, Jesus Julio Camarero, Filipe Campelo, Katarina Cufar, Henri E. Cuny, Martin De Luis, Marek Fajstavr, Alessio Giovannelli, Jožica Gricar, Andreas Gruber, Vladimír Gryc, Aylin Güney, Tuula Jyske, Jakub Kašpar, Gregory King, Cornelia Krause, Audrey Lemay, Feng Liu, Fabio Lombardi, Edurne Martinez del Castillo, Hubert Morin, Cristina Nabais, Pekka Nöjd, Richard L. Peters, Peter Prislan, Antonio Saracino, Vladimir V. Shishov, Irene Swidrak, Hanuš Vavrcík, Joana Vieira, Qiao Zeng, Yu Liu, Sergio Rossi. A critical thermal transition driving spring phenology of
Northern Hemisphere conifers. 2022. Global Change Biology 29(6):1606-1617
DOI : 10.1111/gcb.16543
Despite growing interest in predicting plant phenological shifts,advanced spring phenology by global climate change remains debated. Evidence documenting either small or large advancement of spring phenology to rising temperature over the spatio-temporal scales implies a potential existence of a thermal threshold in the responses of forests to global warming. We collected a unique data set of xylem cell-wall-thickening onset dates in 20 coniferous species covering a broad mean annual temperature (MAT) gradient (?3.05 to 22.9°C) across the Northern Hemisphere (latitudes 23°?66°?N). Along the MAT gradient,we identified a threshold temperature (using segmented regression) of 4.9?±?1.1°C,above which the response of xylem phenology to rising temperatures significantly decline. This threshold separates the Northern Hemisphere conifers into cold and warm thermal niches,with MAT and spring forcing being the primary drivers for the onset dates (estimated by linear and Bayesian mixed-effect models),respectively. The identified thermal threshold should be integrated into the Earth-System-Models for a better understanding of spring phenology in response to global warming and an improved prediction of global climate-carbon feedbacks.
Janie Lavoie, Miguel Montoro Girona, Hubert Morin. Les impacts du type de coupe forestière sur la tordeuse des bougeons de l'épinette. 2022. Le Couvert Boréal 18(4):33
Raphaël Chavardes, Lorena Balducci, Yves Bergeron, Véronique Poirier, Pierre Grondin, Hubert Morin, Fabio Gennaretti. Greater tree species diversity and lower intraspecific
competition attenuate impacts from temperature
increases and insect epidemics in boreal forests of
western Quebec, Canada. 2022. Can. J. For. Res. 53(12):48-59
DOI : 10.1139/cjfr-2022-0114
We investigated how the surrounding environment influences the growth of dominant trees and their responses to temperature and insect epidemics in boreal forests of eastern Canada. We focused on 82 black spruce and jack pine focal trees in stands spanning a double gradient of species diversity and soil texture within a 36 km2 area of western Québec. For these trees, we compared their diameter at breast height, growth rates, temperature-growth relations, and growth during insect defoliator epidemics. We used linear models to study how surrounding tree attributes and soil properties affected the growth of focal trees. Models showed that tree growth responses and responses to temperature and insect epidemics were generally negative with higher intraspecific competition and positive with greater tree species diversity. Growth of both species benefitted from lower soil sand content. Our research offers novel insights on the potential role of the surrounding environment, notably tree competition and species diversity, in mitigating the vulnerability of eastern Canada’s boreal trees to anthropogenic climate change and insect epidemics.
Valentina Buttò, Siddhartha Khare, Guillaume Drolet, Jean-Daniel Sylvain, Fabio Gennaretti, Annie Deslauriers, Hubert Morin, Sergio Rossi. Regionwide temporal gradients of carbon allocation allow for shoot growth and latewood formation in boreal black spruce 2021. Global Ecology and Biogeography. 30(8):1657-1670
DOI : 10.1111/geb.13340
In boreal ecosystems, phenological events display seasonal patterns. These patterns allow for the development of tissues during the short time window available for growth in cold climates. Primary and secondary growth, two expensive processes for plants, are supposedly modulated in time to optimize allocation of carbon to bud and woody tissues. We aimed to assess the phenology of primary and secondary meristems, testing their relationship over the closed black spruce stands of the commercially exploited forest region in Quebec, Canada.
Location
Quebec, Canada.
Time period
2002–2016.
Major taxa studied
Gymnospermae.
Methods
We combined weekly scaled field observations with Moderate Resolution Imaging Spectroradiometer (MODIS) time series of the normalized difference vegetation index (NDVI) to extract timings of photosynthesis and meristem growth in five black spruce [Picea mariana (Mill.) B.S.P.] stands located along a latitudinal gradient and to assess their relationship. We then tested empirical models based on geographical position and seasonal temperatures to predict wood phenology (i.e., the onset and ending of earlywood and latewood formation), and compared its spatial patterns with existing predictions of bud phenology for the same study area.
Results
Photosynthesis started at the beginning of May, 3 weeks before bud reactivation and the onset of wood growth. Latewood formation started in mid-July, after shoot elongation was completed. For wood phenology models, the residual standard error ranged from 1 week to 12 days. Growth dynamics spatialized across the boreal forest of Quebec varied with the transition between the subarctic and humid continental climate.
Main conclusions
Shoot elongation and latewood formation were temporally separated, providing evidence of a trade-off in structural carbon allocation between primary and secondary growth in trees. Spatial patterns of wood phenology predicted for the black spruce polygons are consistent with spatial patterns of bud phenology, demonstrating synchronized temporal dynamics of meristems at the regional scale.
Maxence Martin, Junior A. Tremblay, Jacques Ibarzabal, Hubert Morin. An indicator species highlights continuous deadwood supply is a key ecological attribute of boreal old-growth forests. 2021. Ecosphere 12(5):e03507
DOI : 10.1002/ecs2.3507
Abstract Old-growth forests are optimal habitats for many woodpeckers, which are often themselves excellent indicators of deadwood-associated biodiversity. Old-growth forests are, however, heterogeneous ecosystems in terms of structure, composition, and deadwood characteristics, thus implying a varied use of these forests by woodpeckers. In boreal landscapes, old-growth stands are threatened by forest harvesting; however, there is little information in regard to the consequences for biodiversity with the loss of specific types of old-growth forests. This study aimed to assess how the black-backed woodpecker (Picoides arcticus), a biodiversity indicator species associated with old-growth forest attributes, uses different types of old-growth forests for its foraging needs. We identified woodpecker foraging marks in 24 boreal old-growth forest stands in eastern Canada that were dominated by black spruce (Picea mariana), located within the home range of eight black-backed woodpeckers. We identified the various old-growth forest types using a typology based on the structural attributes of old-growth stands. We classified the sampled stands into four old-growth forest types, corresponding to different successional stages (recent or old, relative to the onset of the old-growth stage), composition (pure black spruce or mixed black spruce–balsam fir [Abies balsamea]), and productivity (ongoing paludification or not). The black-backed woodpecker foraged in all types of old-growth forests, but favored dense old-growth forests that were not paludified and that showed a high temporal continuity (i.e., old-growth dynamics probably started more than a century ago). The temporal continuity of the old-growth state allows for the continuous supply of large, slightly decayed snags, the preferred foraging substrates of the black-backed woodpecker. The old-growth forest type most favored by this woodpecker is, however, also the forest type most often targeted first by logging operations. Protecting the biodiversity associated with recent deadwood in managed areas thus requires maintaining a sufficient area and density of dense, old-growth black spruce-dominated forests in managed areas.
Maxence Martin, Hubert Morin, Nicole J. Fenton. Tree-related microhabitats and deadwood dynamics form a diverse and constantly changing mosaic of habitats in boreal old-growth forests 2021. Ecological Indicator 128:107813
DOI : 10.1016/j.ecolind.2021.107813
Tree-related microhabitats (TreM) and deadwood are two forest attributes providing essential resources for biodiversity conservation and ecosystem services. Old-growth forests are generally defined by a high abundance and diversity of TreM and deadwood, but little is known about TreM and deadwood dynamics once the old-growth stage is reached, in particular in the boreal biome. In this context, knowledge on TreM and deadwood dynamics in old-growth forest stands is necessary to better understand how these forests contribute to biodiversity and ecosystem services. The aim of this study is thus to determine how TreM, and deadwood abundance and diversity vary within boreal old-growth forests. To reach this objective, we surveyed TreM and deadwood attributes, as well as structural and abiotic attributes, in 71 boreal old-growth forests situated in Quebec, Canada. We used hierarchical clustering analysis to identify TreM and deadwood abundance and diversity patterns in the studied stands. We identified five clusters of TreM and deadwood characteristics, which corresponded to three stages of old-growth forest succession: canopy break-up (beginning of the old-growth stage), transition old-growth stage (replacement of the first cohort by old-growth cohorts) and true old-growth stage (first cohort all or almost all gone). The peak in TreM richness and diversity was reached at the transition old-growth stage, whereas the peak for deadwood richness and diversity was reached at the true old-growth stage. Overall, true old-growth forests were defined by a combination of moderate to high TreM density and high deadwood volume, but these values significantly varied among stands depending on past secondary disturbances, stand structure and its composition (black spruce [Picea mariana Mill.] dominated vs mixed black spruce – balsam fir [Abies balsamea (L.) Mill.]). These results therefore underscore the importance of considering old-growth forests as dynamic rather than static ecosystems, as the composition of tree- and deadwood-related microhabitats in the same old-growth stand may markedly change over time. At landscape scale, these results also imply that the mosaic of habitats present in old-growth forests can vary greatly from one location to another, highlighting the importance of maintaining a diversity of old-growth forest structure and composition.
Janie Lavoie, Miguel Montoro Girona, Guillaume Grosbois, Hubert Morin. Does the type of silvicultural practice influence spruce budworm defoliation of seedlings? 2021. Ecosphere 12(4):e03506
DOI : 10.1002/ecs2.3506
Spruce budworm (Choristoneura fumiferana (Clem)) is the main defoliator in the boreal forest of North America, and its outbreaks have major ecological and economic consequences and represent a challenge for forest management. Numerous studies have addressed the effects of this defoliator on mature trees, whereas the effects of spruce budworm on regeneration remain elusive. Furthermore, intensive exploitation practices during the last decades have left a large area of the Canadian boreal forest in an early development stage. In this context, it becomes vital to understand those factors affecting the severity of spruce budworm‐related defoliation on regeneration. Here, we determine the defoliation severity of black spruce and balsam fir seedlings in both mature pure black spruce and black spruce–balsam fir stands subjected to two different silvicultural treatments (clear‐cutting and partial cutting). Defoliation intensity varied between stand types, silvicultural treatments, species, and height classes. Seedlings in black spruce–balsam fir stands experienced twice the defoliation of those in pure black spruce stands (black spruce seedlings 10% vs. 23%; balsam fir seedlings 29% vs. 47%, respectively). Harvesting methods also influenced seedling defoliation. Under clear‐cutting, black spruce seedlings (24%) were three times as defoliated as black spruce seedlings in partial cutting stands (8%), whereas balsam fir seedlings in clear‐cutting plots experienced twice the defoliation (42%) of balsam fir seedlings in partial cutting plots (20%). The level of defoliation also increased with seedling height. This study will help silvicultural strategies adapt to the effects of natural disturbance regimes. As the intensity and severity of defoliator outbreaks are expected to increase under climate change, these results will help guide forest management strategies to select harvesting methods that will limit the effects of defoliation on conifer regeneration.
Raphaël Chavardes, Fabio Gennaretti, Xavier Cavard, Pierre Grondin, Hubert Morin, Yves Bergeron. Role of Mixed-Species Stands in Attenuating the Vulnerability of Boreal Forests to Climate Change and Insect Epidemics. 2021. Frontiers in Plant Science 12:658880
DOI : 10.3389/fpls.2021.658880
We investigated whether stand species mixture can attenuate the vulnerability of eastern Canada’s boreal forests to climate change and insect epidemics. For this, we focused on two dominant boreal species, black spruce [Picea mariana (Mill.) BSP] and trembling aspen (Populus tremuloides Michx.), in stands dominated by black spruce or trembling aspen (“pure stands”), and mixed stands (M) composed of both species within a 36 km2 study area in the Nord-du-Québec region. For each species in each stand composition type, we tested climate-growth relations and assessed the impacts on growth by recorded insect epidemics of a black spruce defoliator, the spruce budworm (SBW) [Choristoneura fumiferana (Clem.)], and a trembling aspen defoliator, the forest tent caterpillar (FTC; Malacosoma disstria Hübn.). We implemented linear models in a Bayesian framework to explain baseline and long-term trends in tree growth for each species according to stand composition type and to differentiate the influences of climate and insect epidemics on tree growth. Overall, we found climate vulnerability was lower for black spruce in mixed stands than in pure stands, while trembling aspen was less sensitive to climate than spruce, and aspen did not present differences in responses based on stand mixture. We did not find any reduction of vulnerability for mixed stands to insect epidemics in the host species, but the non-host species in mixed stands could respond positively to epidemics affecting the host species, thus contributing to stabilize ecosystem-scale growth over time. Our findings partially support boreal forest management strategies including stand species mixture to foster forests that are resilient to climate change and insect epidemics.
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Sanghyun Kim, Miguel Montoro Girona, Patricia Raymond, Annie DesRochers, Hubert Morin, Yves Bergeron. Effects of Partial Harvest and Stand Structure on Conifer Regeneration in Black Spruce Stands: The MISA Project 15e colloque annuel du CEF, Université de Sherbrooke, Québec (2022-09-29)
Anoj Subedi, Philippe Marchand, Yves Bergeron, Hubert Morin, Miguel Montoro Girona. Climate warming reduces black spruce growth during an outbreak period 15e colloque annuel du CEF, Université de Sherbrooke, Québec (2022-09-28)
Maxence Martin, Hubert Morin, Osvaldo Valeria. "Old" is not precise enough: a finer knowledge of old-growth boreal forests is critical to successful conservation and management strategies Conférence annuelle de l’Association Botanique Canadienne. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2022-06-08)
Inès Diamant, Maxence Martin, Junior Tremblay, Hubert Morin, Jacques Ibarzabal. Boreal birds and all you've ever wanted to know about their favorite structural attributes in mixed old-growth forest Conférence annuelle de l’Association Botanique Canadienne. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2022-06-06)
Hubert Morin Huit mille ans d’histoire des épidémies de la TBE Colloques du SCF-CFL (2022-01-27)
Sanghyun Kim, Miguel Montoro Girona, Patricia Raymond, Annie DesRochers, Hubert Morin, Christine Martineau, Yves Bergeron. Can partial harvest promote conifer regeneration and soil ecosystem in black spruce stands? 23e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue (2021-12-07)
Anoj Subedi, Miguel Montoro Girona, Philippe Marchand, Yves Bergeron, Hubert Morin. Comment la tordeuse des bourgeons de l'épinette affecte la croissance des arbres ? une approche dendrochronologique et climatique 23e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue (2021-12-07)
Milva Druguet Dayras, Damien Rius, Hubert Morin, Eve Afonso, Hugues Terreaux de felice, Miguel Montoro Girona. Voyage dans le passé pour reconstruire les régimes de perturbations naturelles dans les forêts boréales : une approche multiple 23e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue (2021-12-07)
Pierre Grondin, Maxence Martin, Hubert Morin, Yan Boucher. La tordeuse des bourgeons de l’épinette : moteur de la dynamique des vieilles forêts boréales et source d’inspiration pour l’aménagement écosystémique? Les Rendez-vous de la connaissance en aménagement forestier durable MFFP - Les ravageurs forestiers (2021-05-18)
Janie Lavoie, Maxence Martin, Annie Deslauriers, Mathieu Bouchard, Joshua Jarry, Anne-Sophie Caron, Hubert Morin. Rendez-vous de la connaissance en aménagement forestier durable - Ravageurs forestiers Rendez-vous de la connaissance en aménagement forestier durable (2021-05-18)
Maxence Martin, Osvaldo Valeria, Hubert Morin, Nicole J. Fenton. Quand on voit flou, il est temps de changer de lunettes : les atouts du LiDAR pour notre regard sur la forêt boréale 22e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, complètement virtuel (2020-12-02)
Anoj Subedi, Miguel Montoro Girona, Philippe Marchand, Hubert Morin, Marie-Josée Fortin. Understanding complex interactions in forest ecosystems : Impact of climate on the defoliation of black spruce by the spruce budworm 22e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, complètement virtuel (2020-12-02)
Raphaël Chavardes, Fabio Gennaretti, Xavier Cavard, Pierre Grondin, Lorena Balducci, Hubert Morin, Alain Leduc, Ari Kainelainen, Danielle Charron, T. Châtellier, Yves Bergeron. Le mélange des espèces dans le peuplement peut-il atténuer la vulnérabilité des forêts boréales aux changements climatiques et aux épidémies d’insectes ? 22e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, complètement virtuel (2020-12-02)
Philippe Marchand, Miguel Montoro Girona, Mathieu Bouchard, Élise Filotas, Hubert Morin, Louis De Grandpré, Yves Bergeron, Pierre Therrien, Anouschka R. Hof, Matthew Duveneck. Projections de l’activité de la tordeuse des bourgeons de l’épinette dans un contexte de changement climatique 21e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2019-11-30)
Janie Lavoie, Hubert Morin, Miguel Montoro Girona. Impacts de la TBE sur la régénération d’épinettes
noires selon différentes coupes forestières 21e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2019-11-30)
Hubert Morin La dynamique spatiale et temporelle des épidémies de la Tordeuse des bourgeons de l’épinette en Amérique du Nord : Une analyse multi-proxy. La dynamique spatiale et temporelle des épidémies (2009-11-17)
Olivier Desjardins, Hubert Morin, Yves Bergeron. Influence de la proportion des deux espèces hôtes de la tordeuse, au niveau du peuplement et du paysage, sur l'impact et le synchronisme des épidémies 69ième congrès annuel de l’ACFAS. Université Sherbrooke, Sherbrooke, Québec, Canada.
Olivier Desjardins, Hubert Morin, Yves Bergeron. Impact of the last spruce budworm outbreak in Quebec and Ontario in relation to the balsam fir relative proportion in a stand 85th Annual Meeting of the Ecological Society of America, Snowbird, Utah, USA.
Olivier Desjardins, Hubert Morin, Yves Bergeron. Influence of balsam fir content, at the stand level, on the impact of the last spruce budworm outbreak in the boreal forest of eastern Canada 3rd International Workshop on 3rd International Workshop on Disturbance dynamics in boreal forests. Kuhmo, Finland.
Sylvain Parent, Hubert Morin, Christian Messier. Cernes manquants au collet chez le sapin baumier 3e colloque annuel du GREFi, Montréal, Québec, Canada.