Nathan Egande, Victor Danneyrolles, Dominique Arseneault, Marie-Eve Sigouin, Yves Bergeron. Transformations de la composition forestière dans les forêts boréales mixtes soumises à une forte influence humaine : une analyse de la région de Rouyn-Noranda de 1910 à 2020 (Québec, Canada) 2024. Can. J. For. Res. 992
DOI : 10.1139/cjfr-2023-0244
Les caractéristiques des forêts préindustrielles permettent d?établir des états de référence pour l'aménagement durable des forêts. Cette approche historique est particulièrement pertinente pour les régions soumises à une forte influence humaine, dans lesquelles les forêts naturelles sont rares. C'est le cas de la région de Rouyn-Noranda, à l'ouest du Québec. Nous avons utilisé les archives d'arpentage disponibles pour reconstituer la composition préindustrielle des forêts boréales mixtes de cette région. ? partir d'une base de données comportant 3621 observations sur la composition historique des forêts (1909?1940), nous dressons un portrait des forêts préindustrielles et des changements survenus dans la région. ? l?époque préindustrielle, les épinettes représentaient les espèces les plus abondantes: elles étaient présentes dans 85,5 % des observations, et étaient identifiées comme dominantes (c.-à-d., les plus abondantes localement) dans 63,9 % des observations. Les épinettes tendaient à être abondantes sur l'ensemble du territoire et des types de dépôts de surface. Entre les époques préindustrielle et moderne (1980?2020), nos résultats montrent une augmentation de la fréquence des feuillus de début de succession, dont principalement le peuplier faux tremble (+28 %). Ces changements de composition semblent attribuables à la combinaison de perturbations (feux, coupes, agriculture, etc.). Nous discutons finalement des implications de ces résultats pour les stratégies d'aménagement écosystémique dans la région.
Victor Danneyrolles, Yan Boucher, Richard Fournier, Osvaldo Valeria. Positive effects of projected climate change on post-disturbance forest regrowth rates in northeastern North American boreal forests. 2023. Environnemental Research Letter 18:024041
DOI : 10.1088/1748-9326/acb72a
Forest anthropogenic and natural stand-replacing disturbances are increasing worldwide due to global change. Many uncertainties regarding the regeneration and growth of these young forests remain within the context of changing climate. In this study, we investigate the effects of climate, tree species composition, and other landscape-scale environmental variables upon boreal forest regrowth following clearcut logging in eastern Canada. Our main objective was to predict the effects of future climate changes upon post-logging forest height regrowth at a subcontinental scale using high spatial resolution remote sensing data. We modeled forest canopy height (estimated from airborne laser scanning [LiDAR] data over 20 m resolution virtual plots) as a function of time elapsed since the last clearcut along with climate (i.e. temperature and moisture), tree species composition, and other environmental variables (e.g. topography and soil hydrology). Once trained and validated with ∼240 000 plots, the model that was developed in this study was used to predict potential post-logging canopy height regrowth at 20 m resolution across a 240 000 km2 area following scenarios depicting a range of projected changes in temperature and moisture across the region for 2041–2070. Our results predict an overall beneficial, but limited effect of projected climate changes upon forest regrowth rates in our study area. Stimulatory effects of projected climate change were more pronounced for conifer forests, with growth rates increasing between +5% and +50% over the study area, while mixed and broadleaved forests recorded changes that mostly ranged from −5% to +35%. Predicted increased regrowth rates were mainly associated with increased temperature, while changes in climate moisture had a minor effect. We conclude that such growth gains could partially compensate for the inevitable increase in natural disturbances but should not allow any increase in harvested volumes.
Raphaël Chavardes, Victor Danneyrolles, Jeanne Portier, Martin-Philippe Girardin, Dorian Gaboriau, Sylvie Gauthier, Igor Drobyshev, Tuomo Wallenius, Dominic Cyr, Yves Bergeron. Converging and diverging burn rates in North American boreal forests from the Little Ice Age to the present 2022. International Journal of Wildland Fire 31(12):1184-1193
DOI : 10.1071/WF22090
Warning: This article contains terms, descriptions, and opinions used for historical context that may be culturally sensitive for some readers.Background: Understanding drivers of boreal forest dynamics supports adaptation strategies in the context of climate change.Aims: We aimed to understand how burn rates varied since the early 1700s in North American boreal forests.Methods: We used 16 fire-history study sites distributed across such forests and investigated variation in burn rates for the historical period spanning 1700-1990. These were benchmarked against recent burn rates estimated for the modern period spanning 1980-2020 using various data sources.Key results: Burn rates during the historical period for most sites showed a declining trend, particularly during the early to mid 1900s. Compared to the historical period, the modern period showed less variable and lower burn rates across sites. Mean burn rates during the modern period presented divergent trends among eastern versus northwestern sites, with increasing trends in mean burn rates in most northwestern North American sites.Conclusions: The synchronicity of trends suggests that large spatial patterns of atmospheric conditions drove burn rates in addition to regional changes in land use like fire exclusion and suppression.Implications: Low burn rates in eastern Canadian boreal forests may continue unless climate change overrides the capacity to suppress fire.
Batistin Bour, Victor Danneyrolles, Yan Boucher, Richard Fournier, Luc Guindon. Modeling post-logging height growth of black spruce-dominated boreal forests by combining airborne LiDAR and time since harvest maps 2021. For. Ecol. Manage. 119697
DOI : 10.1016/j.foreco.2021.119697
Increase in forest disturbance due to land use as well as climate change has led to an expansion of young forests worldwide, which drives global carbon dynamics and timber allocation. This study presents a method that combines a single airborne LiDAR acquisition and time since harvest maps to model height growth of post-logged black spruce-dominated forests in a 1700 km2 eastern Canadian boreal landscape. We developed a random forest model in which forest height at a 20 m × 20 m pixel resolution is a function of stand age, combined with environmental variables (e.g., slope, site moisture, surface deposit). Our results highlight the model's strong predictive power: least-square regression between predicted and observed height of our validation dataset was very close to the 1:1 relation and strongly supported by validation metrics (R2 = 0.74; relative RMSE = 19%). Environmental variables thus allowed to accurately predict forest productivity with a high spatial resolution (20 m × 20 m pixels) and predicted forest height growth in the first 50 years after logging ranged between 16 and 27 cm·year−1 across the whole study area, with a mean of 20.5 cm·year−1. The spatial patterns of potential height growth were strongly linked to the effect of topographical variables, with better growth rates on mesic slopes compared to poorly drained soils. Such models could have key implications in forest management, for example to maintain forest ecosystem services by adjusting the harvesting rates depending on forest productivity across the landscapes.
Victor Danneyrolles, Dominic Cyr, Yves Bergeron, Martin-Philippe Girardin, Sylvie Gauthier, Hugo Asselin. Influences of climate fluctuations on northeastern North America’s burned areas largely outweigh those of European settlement since AD 1850. 2021. Environmental Research Letters 6(11):114007
DOI : 10.1088/1748-9326/ac2ce7
There is a pressing need for a better understanding of changing forest fire regimes worldwide, especially to separate the relative effects of potential drivers that control burned areas. Here we present a meta-analysis of the impacts of climate fluctuation and Euro-Canadian settlement on burned areas from 1850 to 1990 in a large zone (>100 000 km2) in northern temperate and boreal forests of eastern Canada. Using Cox regression models, we tested for potential statistical relationships between historical burned areas in 12 large landscapes (reconstructed with dendrochronological data) with climate reconstructions, changes in the Euro-Canadian population, and active suppression (all reconstructed at the decadal scale). Our results revealed a dominant impact of climate fluctuations on forest burned areas, with the driest decades showing fire hazards between 5 to 15 times higher than the average decades. Comparatively, the Euro-Canadian settlement had a much weaker effect, having increased burned areas significantly only during less fire-prone climate conditions. During periods of fire-prone climate, burned areas were maximum independent of fluctuations in Euro-Canadian populations. Moreover, the development of active fire suppression did not appear to reduce burned areas. These results suggest that a potential increase in climate moisture deficit and drought may trigger unprecedented burned areas and extreme fire events no matter the effects of anthropogenic ignition or suppression.
Victor Danneyrolles, Mark Vellend, Sébastien Dupuis, Yan Boucher, Jason Laflamme, Yves Bergeron, Gabriel Fortin, Marie Leroyer, André de Römer, Raphaëlle Terrail, Dominique Arseneault. Scale-dependent changes in tree diversity over more than a century in eastern Canada: Landscape diversification and regional homogenization. 2021. Journal of Ecology 109(1):273-283
DOI : 10.1111/1365-2745.13474
- A better understanding of how disturbance impacts tree diversity at different scales is essential for our ability to conserve and manage forest ecosystems in the context of global changes. Here we test the impacts of land use?related disturbances on tree diversity since the 19th century across a broad region (>150,000 km2) of northern temperate forests in eastern Canada.
- We used a large and unique dataset of early land surveys conducted during the 19th century (>130,000 species lists), along with modern forest inventories (>80,000 plots), to analyse long?term changes in taxonomic and functional tree diversity at several scales (grid cell resolutions ranging from 12.5 to 1,600 km2; we refer to one grid cell as a ‘landscape’).
- Our results show that land use?related disturbances have led simultaneously to (a) increased diversity within landscapes and a (b) homogenization at the regional scale (i.e. decreased composition dissimilarity among landscapes). These trends were found for both taxonomic diversity and functional diversity, with temporal changes more pronounced for taxonomic than functional diversity. We also found an increase over time in the strength of correlations between environmental variables and diversity both within and among landscapes.
- Synthesis. Our results support the idea that human?induced impacts on biodiversity are strongly scale?dependent and not necessarily associated with biodiversity loss. This highlights possible ways that human?driven changes in tree diversity might impact forest resistance and resilience to future global changes.
Ibrahim Djerboua, Yves Bergeron, Sylvie Gauthier, Victor Danneyrolles, Osvaldo Valeria. How Initial Forest Cover, Site Characteristics and Fire
Severity Drive the Dynamics of the Southern
Boreal Forest. 2020. Remote sensing 12(23):3957
DOI : 10.3390/rs12233957
Forest fires are a key driver of boreal landscape dynamics and are expected to increase with climate change in the coming decades. A profound understanding of the effects of fire upon boreal forest dynamics is thus critically needed for our ability to manage these ecosystems and conserve their services. In the present study, we investigate the long-term post-fire forest dynamics in the southern boreal forests of western Quebec using historical aerial photographs from the 1930s, alongside with modern aerial photographs from the 1990s. We quantify the changes in forest cover classes (i.e., conifers, mixed and broadleaved) for 16 study sites that were burned between 1940 and 1970. We then analyzed how interactions between pre-fire forest composition, site characteristics and a fire severity weather index (FSWI) affected the probability of changes in forest cover. In the 1930s, half of the cover of sampled sites were coniferous while the other half were broadleaved or mixed. Between the 1930s and the 1990s, 41% of the areas maintained their initial cover while 59% changed. The lowest probability of changes was found with initial coniferous cover and well drained till deposits. Moreover, an important proportion of 1930s broadleaved/mixed cover transitioned to conifers in the 1990s, which was mainly associated with high FSWI and well-drained deposits. Overall, our results highlight a relatively high resistance and resilience of southern boreal coniferous forests to fire, which suggest that future increase in fire frequency may not necessarily result in a drastic loss of conifers. View Full-Text
Sébastien Dupuis, Yan Boucher, Jason Laflamme, Gabriel Fortin, Victor Danneyrolles, Marie Leroyer, Raphaëlle Terrail, Yves Bergeron, Dominique Arseneault. Utilisation couplée des archives d’arpentage
et de la classification écologique pour affiner
les cibles de composition dans l’aménagement
écosystémique des forêts tempérées du Québec. 2020. Mémoire de recherche forestière, Direction de la recherche forestière no 183. 36 p.
Sébastien Dupuis, Gabriel Fortin, Marie Leroyer, André de Römer, Victor Danneyrolles, Raphaëlle Terrail, Mark Vellend, Yan Boucher, Jason Laflamme, Yves Bergeron, Dominique Arseneault. Stronger influence of anthropogenic disturbance than climate change on century-scale compositional changes in northern forests. 2019. Nature - Communications 10:1265
DOI : 10.1038/s41467-019-09265-z
Predicting future ecosystem dynamics depends critically on an improved understanding of how disturbances and climate change have driven long-term ecological changes in the past. Here we assembled a dataset of >100,000 tree species lists from the 19th century across a broad region (>130,000km2) in temperate eastern Canada, as well as recent forest inventories, to test the effects of changes in anthropogenic disturbance, temperature and moisture on forest dynamics. We evaluate changes in forest composition using four indices quantifying the affinities of co-occurring tree species with temperature, drought, light and disturbance. Land-use driven shifts favouring more disturbance-adapted tree species are far stronger than any effects ascribable to climate change, although the responses of species to disturbance are correlated with their expected responses to climate change. As such, anthropogenic and natural disturbances are expected to have large direct effects on forests and also indirect effects via altered responses to future climate change.
Yves Bergeron, Victor Danneyrolles, Dominique Arseneault. Anthropogenic disturbances strengthened tree communityenvironment
relationships at the temperate-boreal interface. 2017. Landscape Ecology 33(2):213-224
DOI : 10.1007/s10980-017-0591-y
Context
Knowledge of how environmental gradients generate changes in community composition across forest landscapes (β-diversity) represents a critical issue in the era of global change, which exerts especially powerful impacts by shifting disturbance regimes.
Objectives
We analyzed the response of tree communities to increased disturbance rates that were linked to European settlement at the temperate-boreal interface of eastern Canada. We tested whether disturbance has led to spatial homogenization or heterogenization, and to decoupling or strengthening of community-environment relationships.
Methods
We used a reconstruction of pre-industrial tree communities based on historical land survey records (1854–1935), together with modern data, to assess changes in tree β-diversity patterns. Then, β-diversity was partitioned into fractions explained by spatial (dbMEM) and environmental variables (latitude, elevation, slope, drainage and surface deposits) in order to assess changes in spatial structures and community-environment relationships.
Results
In pre-industrial times, environmental variables explained only a small proportion of β-diversity since dominant taxa were present across the range of environmental gradients, whereas habitat specialists were very rare. Between pre-industrial and modern times, our analysis highlights an increase in β-diversity and the proportion of β-diversity that was explained by environmental variables. Increased disturbance rates have favored early-successional habitat specialist taxa and reduced the habitat breadth of pre-industrial generalists, thereby increasing the strength of community-environment relationships.
Conclusions
Our results support that disturbance can alter the strength of community-environment relationships and also suggest that functional traits of species within the regional pool could predict whether or not disturbance alters such relationships.
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Yan Boucher, Victor Danneyrolles. Prévention des échecs de régénération en forêt boréale : détermination d'un seuil d'arbres semenciers à maintenir lors de la coupe forestière au Québec 17e colloque annuel du CEF, Université du Québec en Outaouais (2024-05-02)
Victor Danneyrolles, Raphaël Chavardes, Martin-Philippe Girardin, Dorian Gaboriau, Sylvie Gauthier, Yves Bergeron. Changements dans les taux de brûlage des forêts boréales Nord-Américaines de 1700 à aujourd’hui. 3e rencontre annuelle du Laboratoire International de Recherche sur les Forêts Froides. Station touristique Duchesnay, Québec. (2023-10-03)
Victor Danneyrolles Monitoring and Modelling the Structural Dynamics of Disturbed Forests with Airborne LiDAR Data Institut Forestier Canadien : E-LECTURES SERIES (2023-05-31)
Dorian Gaboriau, Raphaël Chavardes, Victor Danneyrolles, Jeanne Portier, Martin-Philippe Girardin, Sylvie Gauthier, Igor Drobyshev. Convergence et divergence des taux de brûlage dans les forêts boréales d'Amérique du Nord, du petit âge glaciaire à aujourd'hui 16e colloque annuel du CEF, Université de Montréal (2023-05-08)
Victor Danneyrolles, Yan Boucher, Richard Fournier, Osvaldo Valeria. Suivi et modélisation de la dynamique structurelle des forêts perturbées avec les données de LiDAR aéroporté 15e colloque annuel du CEF, Université de Sherbrooke, Québec (2022-09-29)
Victor Danneyrolles Quel impact des changements climatiques sur les changements de composition depuis l’époque préindustrielle au sud du Québec ? 13e colloque annuel du CEF, Université du Québec à Chicoutimi (2019-05-01)
Victor Danneyrolles Utilisation des archives d'arpentage pour affiner les cibles de composition pour l'aménagement écosystémique des forêts tempérées du Québec 12e colloque annuel du CEF, Université Laval (2018-04-30)
Victor Danneyrolles Reconstitution historique de la composition forestière au Témiscamingue 18e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2016-12-01)
Victor Danneyrolles Reconstitution de la composition des forêts préindustrielles du
Témiscamingue (Québec) à partir des archives de l’arpentage primitif Soutenance thèse (2016-10-17)
Victor Danneyrolles, Yves Bergeron, Dominique Arseneault. Les forêts des arpenteurs du XIXe siècle : un état de référence pour la composition forestière au Témiscamingue 17e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2015-12-02)
Victor Danneyrolles Les forêts des arpenteurs du XIXe siècle : un état de référence pour la composition forestière au Témiscamingue 16e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2014-11-27)
Victor Danneyrolles LES ÉCOSYSTÈMES FORESTIERS DU XXIe SIÈCLE
FACE AUX CHANGEMENTS GLOBAUX examen synthèse (2014-05-05)