Southern Annular Mode drives multicentury wildfire activity in southern South America

Holz, Andrés; Paritsis, Juan; Mundo, Ignacio A.; Veblen, Thomas T.; Kitzberger, Thomas; Williamson, Grant J.; Aráoz, Ezequiel; Bustos-Schindler, Carlos; González, Mauro E.; Grau, H. Ricardo; Quezada, Juan M.

doi:10.1073/pnas.1705168114

Cited by 73 publications

(68 citation statements)

References 45 publications

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“…The impacts of climate variability on both episodic fire events and longer‐term fire trends have received increased attention in recent years due to observed changes in fire activity (Andela et al, ; Turco et al, ; Westerling, ). Efforts to better understand how climate factors contributed to observed changes (Abatzoglou & Williams, ; Holz et al, ) and how fire activity will change in the coming decades in response to climatic and nonclimatic drivers (Knorr, Jiang, & Arneth, ; Moritz et al, ; Pechony & Shindell, ) are essential to refine estimates of changes in biogeochemical cycling, vegetation composition, and fire‐related hazards.…”

Section: Introductionmentioning

confidence: 99%

Global patterns of interannual climate–fire relationships

Abatzoglou

Williams

Boschetti

et al. 2018

Global Change Biology

253

180

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Climate shapes geographic and seasonal patterns in global fire activity by mediating vegetation composition, productivity, and desiccation in conjunction with land-use and anthropogenic factors. Yet, the degree to which climate variability affects interannual variability in burned area across Earth is less understood. Two decades of satellite-derived burned area records across forested and nonforested areas were used to examine global interannual climate-fire relationships at ecoregion scales. Measures of fuel aridity exhibited strong positive correlations with forested burned area, with weaker relationships in climatologically drier regions. By contrast, cumulative precipitation antecedent to the fire season exhibited positive correlations to nonforested burned area, with stronger relationships in climatologically drier regions. Climate variability explained roughly one-third of the interannual variability in burned area across global ecoregions. These results highlight the importance of climate variability in enabling fire activity globally, but also identify regions where anthropogenic and other influences may facilitate weaker relationships. Empirical fire modeling efforts can complement process-based global fire models to elucidate how fire activity is likely to change amidst complex interactions among climatic, vegetation, and human factors.

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Section: Introductionmentioning

confidence: 99%

Global patterns of interannual climate–fire relationships

Abatzoglou

Williams

Boschetti

et al. 2018

Global Change Biology

253

180

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“…The upward trend observed in the Southern Annular Mode (SAM), linked to current warming conditions, is tightlty coupled with fire activity in southern South American forests and woodlands, resulting in increased fire synchrony and activity [56]. Clearly, increased warming in Patagonia promotes low fuel moisture levels, favoring extreme fire danger conditions, such as the scenario described in this work, which in turn may allow more intense and severe fires.…”

Section: Discussionmentioning

confidence: 83%

“…Current climatic trends and forecasted warming scenarios for the southern hemisphere are associated with large and more severe fires [55,56]. The upward trend observed in the Southern Annular Mode (SAM), linked to current warming conditions, is tightlty coupled with fire activity in southern South American forests and woodlands, resulting in increased fire synchrony and activity [56].…”

Section: Discussionmentioning

confidence: 99%

Pine Plantations and Invasion Alter Fuel Structure and Potential Fire Behavior in a Patagonian Forest-Steppe Ecotone

Paritsis

Landesmann

Kitzberger

et al. 2018

Forests

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Abstract:Planted and invading non-native plant species can alter fire regimes through changes in fuel loads and in the structure and continuity of fuels, potentially modifying the flammability of native plant communities. Such changes are not easily predicted and deserve system-specific studies. In several regions of the southern hemisphere, exotic pines have been extensively planted in native treeless areas for forestry purposes and have subsequently invaded the native environments. However, studies evaluating alterations in flammability caused by pines in Patagonia are scarce. In the forest-steppe ecotone of northwestern Patagonia, we evaluated fine fuels structure and simulated fire behavior in the native shrubby steppe, pine plantations, pine invasions, and mechanically removed invasions to establish the relative ecological vulnerability of these forestry and invasion scenarios to fire. We found that pine plantations and their subsequent invasion in the Patagonian shrubby steppe produced sharp changes in fine fuel amount and its vertical and horizontal continuity. These changes in fuel properties have the potential to affect fire behavior, increasing fire intensity by almost 30 times. Pruning of basal branches in plantations may substantially reduce fire hazard by lowering the probability of fire crowning, and mechanical removal of invasion seems effective in restoring original fuel structure in the native community. The current expansion of pine plantations and subsequent invasions acting synergistically with climate warming and increased human ignitions warrant a highly vulnerable landscape in the near future for northwestern Patagonia if no management actions are undertaken.

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“…Fire is recognized to be a key disturbance shaping forests formed by Araucaria araucana and Nothofagus pumilio (hereafter referred to as Araucaria–Nothofagus forests) in the Andean region of southern South America (Burns, ; González, Veblen, & Sibold, ; Mundo, Kitzberger, Roig Junent, Villalba, & Barrera, ; Holz et al, ). Araucaria–Nothofagus forests are typically shaped by a mixed‐severity fire regime that includes surface and crown fires ignited by lightning and anthropogenic sources (González, ).…”

Section: Introductionmentioning

confidence: 99%

Initial response of understorey vegetation and tree regeneration to a mixed‐severity fire in old‐growth Araucaria–Nothofagus forests

Fuentes‐Ramírez

Salas‐Eljatib

González

et al. 2020

Applied Vegetation Science

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Questions Fire is a key factor influencing Araucaria araucana forests, but the impact of fire severity on the understorey vegetation is not well understood. In this study we seek to answer the following questions: (a) how do initial plant diversity, composition and spatial distribution of the understorey vegetation change in response to different levels of fire severity; and (b) does the abundance of dominant tree species exhibit different patterns across a fire severity gradient shortly after fire? Location Old‐growth Araucaria araucana–Nothofagus pumilio forests in the Andes of south‐central Chile (38° S, 71° W) burned in 2015. Methods We evaluated the post‐fire plant regeneration across a fire severity gradient ranging from unburned forests to areas of high fire severity. One year after fire (in February 2016), we measured woody and herbaceous species richness, abundance, height, origin (native vs exotic species), life forms and the spatial pattern of plant recovery. Results Plant species richness and abundance were significantly higher within the unburned forest and low fire severity areas one year after fire, compared to areas of high and moderate fire severity. Overall, nearly 50% of the species present in the unburned forest were not found in areas of high severity, including the tree Nothofagus pumilio. Rapid vegetative resprouting of pioneer species such as Chusquea culeou resulted in an aggregated spatial distribution of plants after fire. Conclusions Plant diversity and the abundance of Araucaria araucana and Nothofagus pumilio were reduced in areas of high fire severity one year after fire. Exotic species were more abundant within areas of low severity, being likely mediated by cattle browsing. Our research makes clear the potential changes in forest composition and structure if dominant tree species are not capable of recovering after fire. We recommend the exclusion of cattle within fire‐affected areas and planting Nothofagus pumilio in areas of high fire severity.

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Southern Annular Mode drives multicentury wildfire activity in southern South America

Cited by 73 publications

References 45 publications

Global patterns of interannual climate–fire relationships

Global patterns of interannual climate–fire relationships

Pine Plantations and Invasion Alter Fuel Structure and Potential Fire Behavior in a Patagonian Forest-Steppe Ecotone

Initial response of understorey vegetation and tree regeneration to a mixed‐severity fire in old‐growth Araucaria–Nothofagus forests

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