Regional drought synchronised historical fires in dry forests of the Montane Cordillera Ecozone, Canada

Abstract

Understanding climate as a driver of low- to moderate-severity fires in the Montane Cordillera Ecozone of Canada is a priority given predicted and observed increases in frequency and severity of large fires due to climate change. We characterised historical fire-climate associations using 14 crossdated fire-scar records and tree-ring proxy reconstructions of summer drought and annual precipitation from the region. We compared fire-climate associations among years when fires burned in multiple study areas. From 1746 to 1945, there were 32 years with moderate fire synchrony in which four to six study areas recorded fire. During four high fire synchrony years, 7 to 10 study areas recorded fire. Below-average annual precipitation and summer drought synchronised fires, whereas infrequent years of high fire synchrony were preceded by a wet summer. After 1945, decreased fire occurrence and synchrony reflects fire exclusion, suppression and climatic variation. Global climate change manifests as blocking high-pressure ridges that superimpose on longer fire-seasons and increased droughts. Combined, they make dry forests increasingly susceptible to synchronous fires, which are difficult to suppress as observed during the record-breaking 2017, 2018 and 2021 fire seasons in British Columbia.

Mathematical Simulation of Forest Fuel Pyrolysis and Crown Forest Fire Impact for Forest Fire Danger and Risk Assessment

“…The first three components describe the moisture content of forest fuel of different sizes [30]. Today, research is being actively carried out aimed at choosing the optimal criteria for use in predicting systems for forest fire danger for a specific area [31][32][33]. Thus, the main empirical drought indices were tested in the conditions of the European Mediterranean by the correlation with real data on fuel moisture [33].…”

“…Today, research is being actively carried out aimed at choosing the optimal criteria for use in predicting systems for forest fire danger for a specific area [31][32][33]. Thus, the main empirical drought indices were tested in the conditions of the European Mediterranean by the correlation with real data on fuel moisture [33]. The final statistical analysis of the collected data showed that the KBDI is the most appropriate one for the considered conditions.…”

A century of transformation: fire regime transitions from 1919 to 2019 in southeastern British Columbia, Canada

“…Furthermore, owing to improved data accuracy and availability, previous analyses focused on datasets beginning in the mid-to late-20 th century at regional (Burton et al 2008;Albert-Green et al 2013;Veraverbeke et al 2017;Campos-Ruiz 2018) and national scales (Coogan et al, 2020;Coops et al, 2018;Hanes et al, 2019). These studies generally investigated fire regime changes using a single trend line, despite multiple lines of evidence that fire regimes through the 20 th century have been spatially and temporally dynamic (Naficy et al 2015;Hessburg et al 2019;Chavardès et al 2021;Hagmann et al 2021). In British Columbia (BC), provincial fire records cover 94.4 million hectares (ha) and represent the greatest time depth of digitized fire events available in Canada (BC Wildfire Service 2021a; Skakun et al 2021).…”

“…Accompanying the rapidly declining effectiveness of fire suppression under extreme fire weather conditions (Wotton et al 2017), these severe fire seasons sharply contrast with 20 th century fire regimes (Hanes et al 2019;Coogan et al 2020). In the East Kootenay forest region of southeastern BC, contemporary wildfire risk (Kirchmeier-Young et al 2017;Johnston et al 2020) and disrupted low-and mixed-severity fire regimes shaped by Indigenous burning (Marcoux et al 2015;Chavardès et al 2021;Greene 2021) incentivize an improved understanding of fire regime transitions.…”

Incendios forestales en bosques de <i>Araucaria araucana</i>: susceptibilidad de los diferentes tipos forestales a quemarse y mecanismos de retroalimentación causales de la recurrencia de incendios en el contexto actual de cambio climático

“…La magnitud de estos efectos difiere según el tipo de vegetación, pudiendo reducirse la incidencia de incendios en regiones donde las condiciones más áridas limitan la producción de biomasa (Moritz et al 2012;McKenzie & Littell 2017). Sin embargo, en general se predice que la interacción entre las sequías y los incendios resulte en un incremento en la actividad del fuego (Littell et al 2009), como reflejan las reconstrucciones de historia de incendios en diversos bosques (Mundo et al 2013;Chavardès et al 2021). En consecuencia, se espera que la mayor magnitud y frecuencia de sequías, proyectadas en el contexto de calentamiento global, propicien la ocurrencia de incendios más severos y frecuentes e incluso extiendan la duración de la temporada de incendios (Lestienne et al 2022).…”