Interannual climate variability drives regional fires in west central British Columbia, Canada

Abstract

We investigated the influence of climate variability on forest fire occurrence at eight sites in west central British Columbia, Canada. Forty‐six local fire years affecting a single site and 16 moderate fire years affecting two or more sites were identified (1600–1900 A.D.). Existing fire history data were incorporated to identify 17 regionally synchronous fire years (fires that affected ≥3 sites). Interannual and multidecadal relationships between fire occurrence and the Palmer Drought Severity Index (PDSI), El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and the Pacific North American (PNA) pattern were examined, in addition to the effects of additive positive phases of ENSO and PDO. We examined multiple reconstructions of ENSO, PDO, and PNA and utilized three methodological approaches to characterize climate‐fire relationships. We found that the influence of interannual climate, expressed as PDSI, increasingly synchronized the occurrence of fires when examined from local to regional scales. An association between local fires and positive antecedent moisture conditions suggests moisture‐driven fine fuel development and the proximity of some sites to grasslands likely function as key determinants of local‐scale fire activity. The relationships between regional fires and ENSO, PDO, and PNA suggest that large‐scale patterns of climate variability exert a weak and/or inconsistent influence over fire activity in west central British Columbia between 1700 and 1900 A.D. Although inconsistent among reconstructions of climate patterns, we identified a significant relationship between regional fires and large‐scale climate patterns when ENSO and PDO were both in positive phases.

Disturbance–climate relationships between wildfire and western spruce budworm in interior British Columbia

“…). The number of samples collected, number of fire years, and mean return interval are presented by individual site, and details are reported in Harvey and Smith ().…”

“…Fire‐scarred trees were identified and sampled within 30–40 ha search areas to construct site‐level fire histories as described in Harvey and Smith (). At Black Dome, the grassland fire chronology reported in Harvey et al.…”

“…Regional fire histories were constructed for grassland sites and for non‐grassland sites by pooling all the years when fires were recorded between 1600 and 1900 AD. Fires occurring after 1900 AD were excluded from the analyses (Harvey and Smith ).…”

Drought-Modulated Boreal Forest Fire Occurrence and Linkage with La Nina Events in Altai Mountains, Northwest China

“…In contrast, the dry condition in association with warm ENSO (El Nino) and PDO phases have led to significantly increased forest fire intensity in most of China [40], southeast Asia [41], central to eastern America [24,42,43], southeast Australia [44,45], and tropical rain forests [46]. A warm ENSO-warm PDO combination has greatly increased the fire risk, frequency, and burned area in the boreal forests in North America and Northeast China [26,[47][48][49][50] as well as wildfire emissions in the northern high latitudes [51]. However, the impacts of ENSO and PDO on boreal forest fires in nonmonsoonal regions, especially in inland Asia, is still unclear.…”

Drought Modulated Boreal Forest Fire Occurrence and Linkage with La Nina Events in Altai Mountains, Northwest China

“…In contrast, the dry condition in association with warm ENSO (El Nino) and PDO phases have led to significantly increased forest fire intensity in most China [39], Southeast Asia [40], central to eastern America [23,41,42], southeast Australia [43,44], and tropical rain forests [45]. A warm ENSO-warm PDO combination has greatly increased fire risks, frequency and burned area in the boreal forests in North America and Northeast China [25,[46][47][48][49], and wildfire emissions in the northern high latitudes [50]. However, the impacts of ENSO and PDO on the boreal forest fire of none-monsoonal regions, especially in inland Asia is still unclear.…”