Drivers and Impacts of the Record-Breaking 2023 Wildfire Season in Canada

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Aug. 20, 2024

Abstract The 2023 wildfire season in Canada was unprecedented its scale and intensity, spanning from mid-April to late October across much of the forested regions Canada. Here, we summarize main causes impacts this exceptional season. record-breaking total area burned (~15 Mha) can be attributed several environmental factors that converged early season: snowmelt, multiannual drought conditions western Canada, rapid transition eastern Anthropogenic climate change enabled sustained extreme fire weather conditions, as mean May–October temperature over 2.2 °C warmer than 1991–2020 average. were profound with more 200 communities evacuated, millions exposed hazardous air quality smoke, unmatched demands on fire-fighting resources. not only set new records, but highlights increasing challenges posed by wildfires

Language: Английский

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Canada Under Fire – Drivers and Impacts of the Record-Breaking 2023 Wildfire Season

Authorea (Authorea), Journal Year: 2024, Volume and Issue: unknown

Published: Feb. 28, 2024

The 2023 wildfire season in Canada was unprecedented its scale and intensity. Spanning from late April to early November extending across much of the forested regions Canada, resulted a record-breaking total area burned approximately 15 million hectares, over seven times historic national annual average. impacts were profound with more than 200 communities evacuated (approximately 232,000 people), periods dense smoke that caused significant public health concerns, demands on fire-fighting resources. exceptional can be attributed several environmental factors converged enable extreme fire danger country. These included snowmelt, interannual drought conditions western rapid transition eastern Canada. Furthermore, mean May-October temperature staggering 2.2°C warmer normal (1991-2020), enabling sustained weather throughout season. led larger proportion very large fires (> 50,000 hectares), many having for months spring into fall. Fires started May or June accounted two-thirds burned. Overall, characterized by major societal impacts, setting new records highlighting increasing challenges posed wildfires

Language: Английский

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Boreal forest cover was reduced in the mid-Holocene with warming and recurring wildfires

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: April 3, 2024

Abstract The hemi-boreal zone, marking North America’s southern boreal forest boundary, has evolved post-glaciation, hosting diverse ecosystems including mixed forests with savannas, grasslands, and wetlands. While human, climate, fire interactions shape vegetation dynamics therein, specific influences remain unclear. Here we unveil 12,000 years of zone dynamics, exploring wildfire, vegetation, human population size at such long time scales. Postglacial biomass burning exhibited episodes persistent elevated activity, a pivotal shift around 7000 ago saw the transition to an oak-pine barren ecosystem for about 2000 before reverting. This mid-Holocene occurred during period more frequent sudden uptick in mean annual temperatures. Population Indigenous peoples mirrored wildfire fluctuations, decreasing burning. Anticipated increases activity climate change are expected echo transformations observed ago, reducing extent, impacting land use.

Language: Английский

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Flowering time responses to warming drive reproductive fitness in a changing Arctic

Annals of Botany, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 22, 2024

Abstract Background and Aims The Arctic is warming at an alarming rate, leading to earlier spring conditions plant phenology. It often unclear what degree changes in reproductive fitness (flower, fruit seed production) are a direct response versus indirect through shifting aim of this study was quantify the relative importance these pathways project net effects on phenology under current future climate scenarios. Methods We used two long-term datasets 12 tundra species Canadian as part International Tundra Experiment (ITEX). Phenology were recorded annually tagged individual plants both Daring Lake, Northwest Territories (64° 52' N, - 111° 35' W) Alexandra Fiord, Nunavut (78° 49' 75° 48' W). encompassed wide taxonomic diversity across range functional types with circumpolar/boreal distributions. hierarchical Bayesian structural equation models compare species, sites years. Key Results found that warming, experimental ambient, drove flowering which led higher numbers flowers fruits produced, reflecting directional phenotypic selection for Furthermore, effect mediated generally about three times stronger than fitness. Under predictions, showed ~2- 4.5-fold increase their (flower counts) advanced Conclusions Our results suggest that, average, benefits early flowering, such increased development time subsequent enhanced fitness, might outweigh its risks. Overall, work provides important insights into population-level consequences phenological shifts over multi-decadal scales.

Language: Английский

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A modest increase in fire weather overcomes resistance to fire spread in recently burned boreal forests

Global Change Biology, Journal Year: 2024, Volume and Issue: 30(6)

Published: June 1, 2024

Abstract Recently burned boreal forests have lower aboveground fuel loads, generating a negative feedback to subsequent wildfires. Despite this feedback, short‐interval reburns (≤20 years between fires) are possible under extreme weather conditions. Reburns consequences for ecosystem recovery, leading enduring vegetation change. In study, we characterize the strength of fire‐fuel in recently Canadian and conditions that overwhelm resistance fire spread areas. We used dataset daily thousands large fires, interpolated from remotely sensed thermal anomalies which associated local ERA5‐Land each day fire's duration. classified days with >3 ha growth as defined pixels overlapping perimeter ≤20 old reburns. Results logistic regression showed odds areas were ~50% than long‐interval fires; however, all ecozones experienced reburning (1981–2021), over 100,000 annually. As intensify, declines, allowing The was more during spread, but overall differences modest (e.g. relative humidity 2.6% lower). frequency conducive has significantly increased western forest due climate warming drying (1981–2021). Our results suggest an ongoing degradation feedbacks, is likely continue climatic drying.

Language: Английский

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PDO Dynamics Shape the Fire Regime of Boreal Subarctic Landscapes in the Northwest Territories, Canada

Journal of Geophysical Research Biogeosciences, Journal Year: 2025, Volume and Issue: 130(2)

Published: Feb. 1, 2025

Abstract Spatially explicit reconstructions of fire activity in northwestern boreal Canada are rare, despite their importance for modeling current and future disturbance regimes forest dynamics. We provide a dendrochronological reconstruction historical along Highway 3 the Northwest Territories (NWT), Canada, within subarctic zone. dated 129 fires that occurred between 1202 2015 CE, using samples from 479 fire‐scarred living dead jack pine trees ( Pinus banksiana Lamb.). Three distinct periods can be distinguished terms cycle (FC) occurrence. Initially (1340–1440 CE), was low (FC = 572 years; 1 fire/decade), before increasing notably 1460 1840 171 4.45 fires/decade), even more recent times (1860–2015 CE; FC 95 7.63 fires/decade). Climate has been an important factor controlling changes frequency NWT since 1300s. The 1440s 1850s correspond with increased synchronized shifts negative to positive Pacific Decadal Oscillation (PDO) phases. Since mid‐1800s, human activities may have contributed increase activity, but climate remained leading factor. During 20th century, years area burned corresponded drier‐than‐average conditions associated PDO, suggesting study region is still influenced by climate. Spatial teleconnection patterns among drought, large (LFYs) reveal persistent relationships ocean‐atmosphere circulation activity. PDO dynamics hold strong potential predicting regional hazards across North America.

Language: Английский

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No evidence of a northward biome shift of treeline in the Mackay Lake region, north-central Canada

Ecoscience, Journal Year: 2023, Volume and Issue: 30(2), P. 113 - 129

Published: April 3, 2023

Major changes in boreal and subarctic climates have occurred recent decades, but uncertainty exists as to how biota are responding, e.g., whether the forest-tundra ('treeline') will advance northward. Ground-based vegetation data from Mackay Lake region of Northwest Territories were used determine if there is evidence a northward biome shift. Near treeline, current plant communities similar those documented 40–67 years ago. There was little or no tree regeneration by seed, expansion stands, colonization trees adjacent tundra. Black spruce stems require ~75 reach 2.5 m height be discernible on photography satellite imagery. Branches 20–30 old preferred age for initiation an upright stem layering. Upright clonal within may far younger than their near-ground belowground stems. Whether migration occur depend interplay between climatic, landscape, soil factors, species capacities, wildfires, afforestation outpaces deforestation. In forest-tundra, climatic change not result significant shifts, rather relative abundance already present.

Language: Английский

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Analysis of Wildfire Danger Level Using Logistic Regression Model in Sichuan Province, China

Forests, Journal Year: 2023, Volume and Issue: 14(12), P. 2352 - 2352

Published: Nov. 29, 2023

Sichuan Province preserves numerous rare and ancient species of plants animals, making it an important bio-genetic repository in China even the world. However, this region is also vulnerable to fire disturbance due rich forest resources, complex topography, dry climate, thus has become one main regions needing wildfire prevention. Analyzing driving factors influencing incidence can provide data policy guidance for management Province. Here we analyzed spatial temporal distribution characteristics wildfires based on spot during 2010–2019. Based 14 input variables, including vegetation, human factors, applied Pearson correlation analysis Random Forest methods investigate most occurrence. Then, Logistic model was further predict occurrences. The results showed that: (1) southwestern a high-incidence area wildfires, fires occurred from January June. (2) factor affecting occurrence monthly average temperature, followed by elevation, precipitation, population density, Normalized Difference Vegetation Index (NDVI), NDVI previous month, Road kernel density. (3) prediction yielded good performance, with under curve (AUC) values higher than 0.94, overall accuracy (OA) 86%, true positive rate (TPR) 0.82, threat score (TS) 0.71. final selected AUC 0.944, OA 87.28%, TPR 0.829, TS 0.723. (4) indicate that extremely high danger (probability 0.8) concentrated southwest, which accounted about 1% study region, specifically Panzhihua Liangshan. These findings demonstrated effectiveness predicting Province, providing valuable insights regarding prevention efforts region.

Language: Английский

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Future carbon sequestration potential in a widespread transcontinental boreal tree species: Standing genetic variation matters!

Global Change Biology, Journal Year: 2024, Volume and Issue: 30(6)

Published: June 1, 2024

Climate change (CC) necessitates reforestation/afforestation programs to mitigate its impacts and maximize carbon sequestration. But comprehending how tree growth, a proxy for fitness resilience, responds CC is critical these programs' effectiveness. Variability in response across populations can notably be influenced by the standing genetic variation encompassing both neutral adaptive diversity. Here, framework proposed assess growth potential at population scale while accounting variation. We applied this black spruce (BS, Picea mariana [Mill] B.S.P.), with objectives (1) determine key climate variables having impacted BS from 1974 2019, (2) examine relative roles of local adaptation phylogeographic structure response, (3) project under two Shared Socioeconomic Pathways taking into account. modeled using machine learning algorithm trained dendroecological data obtained over 2600 trees (62 divided three clusters) four 48-year-old common gardens, simulated until year 2100 garden locations. Our study revealed that high summer autumn temperatures negatively growth. As consequence warming, species projected experience decline end century, suggesting maladaptation anticipated threat sequestration capacity. This being said, we observed clear difference within among clusters, western cluster more than central eastern clusters. results show intraspecific variation, associated structure, must considered when estimating widespread CC.

Language: Английский

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Reconstructing the interactions between climate, fire, and vegetation dynamics during the Holocene, North Slave Region, Northwest Territories, Canada

Quaternary Science Reviews, Journal Year: 2024, Volume and Issue: 350, P. 109158 - 109158

Published: Dec. 31, 2024

Language: Английский

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