Past and future wildfire risks and their impacts on the eastern Canadian boreal forest resilience

• Main Author: Chaste, Émeline
• Other Authors: Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres, Université du Québec à Montréal, Christelle Hély-Alleaume, Martin Girardin, Yves Bergeron
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2018
• Subjects: Forest productivity; LPJ-LMfire; Climate change; Forest management; Variability; Productivité forestière; Changements climatiques; Aménagement forestier; Variabilité; [SDE.MCG]Environmental Sciences/Global Changes; [SDV.EE.ECO]Life Sciences [q-bio]/Ecology; environment/Ecosystems; Newfoundland
• Online Access: https://theses.hal.science/tel-02174929; https://theses.hal.science/tel-02174929/document; https://theses.hal.science/tel-02174929/file/2018PSLEP047_archivage.pdf

Changes in forest composition and structure are projected in response to the future climate likely more conducive to fire and water stress. A decrease in carbon and biomass stocks could significantly affect the forest industry and global warming by high carbon emissions during fires. However, despite its ecological and socio-economic importance, the future of the forest is uncertain because the impacts of climate change on ecosystem processes and standing biomass are still poorly understood. The primary objective is therefore to assess the potential effects of climate change on vegetation dynamics and fires, and to characterize their joint effects on the resilience of eastern Canada's boreal forest on both sides of the northern limit of managed forests (NLMF). Simulations were carried out with the LPJ-LMfire dynamic global vegetation model and focused on three specific objectives: (1) to reconstruct fire activity during the 20th century and analyze changes in spatial and temporal fire trends related to vegetation and climate, (2) to analyze the forest response projection to climate change and to fire increase to assess if abrupt changes in biomass of dominant species could occur, (3) to simulate trajectories of past fires and vegetation in response to Holocene climatic variations to understand the relationship between climate, fire and vegetation. For the first time, simulations are performed on the eastern boreal forest with LPJ-LMfire over 6000 years and at high spatial resolution (100 km 2) over a study area stretching west to east, from Manitoba to Newfoundland. The plant functional types for the four dominant tree genera (Picea, Abies, Pinus, Populus) have been parameterized. The predictive capabilities of the model were tested over the 20th century by comparing simulated annual rates of combustion and biomass with independent observations. The same variables, simulated over the past 6,000 years, have been compared to paleoecological reconstructions from lacustrine records of microcharcoals and pollen. ...