Lightning as a major driver of recent large fire years in North American boreal forests

Abstract

General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

Negligent and intentional fires in Portugal: Spatial distribution characterization

“…In fact, on a global scale, humans cause most of the wildfires, except in the boreal areas of North America and Eurasia, where a significant number of natural wildfires occurs and are responsible for a large part of the TBA (Le Page et al, 2015;Rowe and Scotter, 1973;Stocks et al, 2002;Veraverbeke et al, 2017). In Mediterranean-type ecosystems, wildfires are mostly caused (intentionally or negligently) by human activities which vary spatially and temporally in ways that could affect their size and destructiveness (Curt et al, 2016;Pereira et al, 2017;Syphard and Keeley, 2015).…”

Differences in Human versus Lightning Fires between Urban and Rural Areas of the Boreal Forest in Interior Alaska

“…This is especially pronounced in the intensely suppressed Full fire management zone, which constitutes 37% of the subregion, experiences 82% of all human fires in this subregion, and is home to sprawling exurban developments in the WUI. Veraverbeke [29] reported a 4.82% year −1 increase in lightning ignitions since 1975 which is higher than the 2.3% year −1 increase in lightning ignitions we calculated in rural interior Alaska since 1943. Kasischke et al [5] attributed decreasing decadal lightning ignitions since a peak in the 1970s to the following causes: lack of detection of new fires because either fire services were focused on existing fires or smoke from big fires obscured new small fires; another explanation is that in remote areas, several small fires can merge resulting in a reduction in total fire counts despite increased area burned.…”

“…The occurrence of lightning strikes in Alaska seems to be a function of forest cover, intermediate elevation, and weather conducive to lightning development [29,43,61]. Lightning fires are mostly observed in June and July with some fires in August [26] which correspond to recorded lightning strike peaks in June and especially July and a rapid drop in August [45].…”

“…It can be modulated by vegetation [22][23][24], land use [25], and suppression [26][27][28] after being ignited by either lightning strikes [29] or people [30][31][32]. These complex interactions between humans, environmental conditions, and fire are currently not well Human influence on fire in boreal forests diminishes with distance from human settlements, roads, and to some extent railroads [26,27,30,31,46].…”

Were Western European Neandertals Able to Make Fire?

“…3;Montoya et al 2011). Similarly, recent data (Veraverbeke et al 2017) and modelling (Romps et al 2014) also suggest that lightning frequency and lightning-caused wildfires are associated with current global warming. Furthermore, we know that the major cold (glacial) and warm (interglacial) oscillations (and the shorter-term variations within these) that occurred in the Pleistocene clearly resulted in changes in temperature, humidity, and plant biomass and moisture: this has been abundantly documented in the paleontological, palynological, and geological record of Western Europe (e.g., de Beaulieu and Reille 1989;Discamps 2014;Discamps et al 2011;Goni et al 2008;Genty 2008;Guiot et al 1993; Laville 1975; Reille and De Beaulieu 1990;Tzedakis 1994;Woillard 1978).…”