Alaska’s changing fire regime — implications for the vulnerability of its boreal forestsThis article is one of a selection of papers from The Dynamics of Change in Alaska’s Boreal Forests: Resilience and Vulnerability in Response to Climate Warming.

Abstract

A synthesis was carried out to examine Alaska’s boreal forest fire regime. During the 2000s, an average of 767 000 ha·year–1 burned, 50% higher than in any previous decade since the 1940s. Over the past 60 years, there was a decrease in the number of lightning-ignited fires, an increase in extreme lightning-ignited fire events, an increase in human-ignited fires, and a decrease in the number of extreme human-ignited fire events. The fraction of area burned from human-ignited fires fell from 26% for the 1950s and 1960s to 5% for the 1990s and 2000s, a result from the change in fire policy that gave the highest suppression priorities to fire events that occurred near human settlements. The amount of area burned during late-season fires increased over the past two decades. Deeper burning of surface organic layers in black spruce ( Picea mariana (Mill.) BSP) forests occurred during late-growing-season fires and on more well-drained sites. These trends all point to black spruce forests becoming increasingly vulnerable to the combined changes of key characteristics of Alaska’s fire regime, except on poorly drained sites, which are resistant to deep burning. The implications of these fire regime changes to the vulnerability and resilience of Alaska’s boreal forests and land and fire management are discussed.

A refinement of models projecting future Canadian fire regimes using homogeneous fire regime zones

“…), is expected to change drastically over the forthcoming decades in Canada as a result of the more fire-conducive weather linked with climate change. Recent shifts observed in annual area burned (AAB) and fire seasonality in boreal North America (Gillett et al 2004;Kasischke et al 2010) are consistent with recent changes in climate patterns. Several authors project sharp increases in future AAB and in the number of fires (e.g., Flannigan et al 2005;Balshi et al 2009;Wotton et al 2010) as a result of warmer temperatures and more frequent extreme droughts due to frequent blocking high-pressure systems with climate change.…”

Generalizable principles for ecosystem stewardship-based management of social-ecological systems: lessons learned from Alaska

“…In interior Alaska, mean annual temperature, an important press, increased 3°C over the http://www.ecologyandsociety.org/vol19/iss4/art13/ last 60 years (Chapin et al 2014). As a result, wildfires, a key pulse in Alaska, have become more frequent and larger (Weber and Flannigan 1997, Flannigan et al 2009, Kasischke et al 2010. Interactions between these press-and pulse-ecosystem drivers may already be triggering regime shifts in Alaskan SESs, fundamentally altering postwildfire forest regeneration, species assemblages, and local food systems (Johnstone and Chapin 2006, Chapin et al 2008, Johnstone et al 2010, Kofinas et al 2010, Mann et al 2012.…”

Temperature and moisture effects on greenhouse gas emissions from deep active-layer boreal soils

“…High-latitude ecosystems are being subjected to rapid changes in climate (IPCC, 2013) and increases in fire frequency and intensity (Kasischke et al, 2010), notably in northwestern North America and Alaska (Hinzman et al, 2005;Ju and Masek, 2016). This will have a wide variety of ecosystem effects (Alexander and Mack, 2016): in particular, rising temperatures and increasing fire will likely result in changes in soil temperature and permafrost degradation (Pastick et al, 2015;Zhang et al, 2015;Genet et al, 2013;Helbig et al, 2016), with subsequent hydrology changes that will influence soil greenhouse gas (GHG) fluxes to the atmosphere (Schädel et al, 2014).…”