Short- to medium-term effects of crown and surface fires on soil respiration in a Canadian boreal forest

• Main Authors: Ribeiro-Kumara, Caius, Santn, Cristina, Doerr, Stefan H., Pumpanen, Jukka, Baxter, Greg, Kster, Kajar
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: University of Toronto 2022
• Subjects: Canada; Northwest Territories
• Online Access: http://hdl.handle.net/1807/110934; http://www.nrcresearchpress.com/doi/abs/10.1139/cjfr-2021-0354

Fires are an important perturbation for the carbon (C) dynamics of boreal forests, especially when they are stand-replacing. In North American boreal forests, crown fires are predominant and, therefore, the most studied. However, surface fires can also lead to major tree mortality with substantial implications for the C balance. Here, we assess the short- (hours – days) to medium-term (1 – 3 years) effects of the different fire types (surface vs. crown) on the postfire soil C effluxes in jack pine and black spruce forest stands in the Northwest Territories, Canada. We found that while trees were instantly killed by the four crown fires studied, trees also died within one year after two of three surface fires studied. Associated with this tree mortality, soil autotrophic respiration decreased after both fire types, although at different timings. The soil heterotrophic respiration was either lower or unchanged when measured 1 – 3 years after either fire type, but was increased when measured immediately after a surface fire, possibly due to the interaction between ash generation and wetting performed to suppress the fire. Our results suggest that both fire types can thus substantially alter C fluxes in the short- to medium-term, both through changes in vegetation and the soil environment. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.