Drought-induced increase in tree mortality and corresponding decrease in the carbon sink capacity of Canada's boreal forests from 1970 to 2020 |
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Authors: | Qiuyu Liu Changhui Peng Robert Schneider Dominic Cyr Nate G. McDowell Daniel Kneeshaw |
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Affiliation: | 1. Department of Biology Sciences, Institute of Environment Sciences, University of Quebec at Montreal, Montreal, Quebec, Canada;2. University of Quebec at Rimouski—UQAR, Rimouski, Quebec, Canada;3. Science and Technology Branch, Environment and Climate Change Canada, Gatineau, Quebec, Canada;4. Atmospheric Sciences and Global Change Division, Pacific Northwest National Lab, Richland, Washington, USA;5. Centre for Forest Research, University of Quebec at Montreal, Montreal, Quebec, Canada |
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Abstract: | Canada's boreal forests, which occupy approximately 30% of boreal forests worldwide, play an important role in the global carbon budget. However, there is little quantitative information available regarding the spatiotemporal changes in the drought-induced tree mortality of Canada's boreal forests overall and their associated impacts on biomass carbon dynamics. Here, we develop spatiotemporally explicit estimates of drought-induced tree mortality and corresponding biomass carbon sink capacity changes in Canada's boreal forests from 1970 to 2020. We show that the average annual tree mortality rate is approximately 2.7%. Approximately 43% of Canada's boreal forests have experienced significantly increasing tree mortality trends (71% of which are located in the western region of the country), and these trends have accelerated since 2002. This increase in tree mortality has resulted in significant biomass carbon losses at an approximate rate of 1.51 ± 0.29 MgC ha−1 year−1 (95% confidence interval) with an approximate total loss of 0.46 ± 0.09 PgC year−1 (95% confidence interval). Under the drought condition increases predicted for this century, the capacity of Canada's boreal forests to act as a carbon sink will be further reduced, potentially leading to a significant positive climate feedback effect. |
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Keywords: | carbon dynamics carbon starvation climate change drought index hydraulic failure positive feedback process-based model remote sensing |
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