The contribution of Indigenous stewardship to an historical mixed‐severity fire regime in British Columbia, Canada

Abstract

Indigenous land stewardship and mixed‐severity fire regimes both promote landscape heterogeneity, and the relationship between them is an emerging area of research. In our study, we reconstructed the historical fire regime of Ne Sextsine, a 5900‐ha dry, Douglas fir–dominated forest in the traditional territory of the T'exelc (Williams Lake First Nation) in British Columbia, Canada. Between 1550 and 1982 CE, we found median fire intervals of 18 years at the plot level and 4 years at the study‐site level. Ne Sextsine was characterized by an historical mixed‐severity fire regime, dominated by frequent, low‐severity fires as indicated by fire scars, with infrequent, mixed‐severity fires indicated by cohorts. Differentiating low‐ from mixed‐severity plots over time was key to understanding the drivers of the fire regime at Ne Sextsine. Low‐severity plots were coincident with areas of highest use by the T'exelc, including winter village sites, summer fishing camps, and travel corridors. The high fire frequency in low‐severity plots ceased in the 1870s, following the smallpox epidemic, the forced relocation of Indigenous peoples into small reserves, and the prohibition of Indigenous burning. In contrast, the mixed‐severity plots were coincident with areas where forest resources, such as deer or certain berry species, were important. The high fire frequency in the mixed‐severity plots continued until the 1920s when industrial‐scale grazing and logging began, facilitated by the establishment of a nearby railway. T'exelc oral histories and archeological evidence at Ne Sextsine speak to varied land stewardship, reflected in the spatiotemporal complexity of low‐ and mixed‐severity fire plots. Across Ne Sextsine, 63% of cohorts established and persisted in the absence of fire after colonial impacts beginning in the 1860s, resulting in a dense, homogeneous landscape that no longer supports T'exelc values and is more likely to burn at uncharacteristic high severities. This nuanced understanding of the Indigenous contribution to a mixed‐severity fire regime is critical for advancing proactive fire mitigation that is ecoculturally relevant and guided by Indigenous expertise.

Fire severity drives understory community dynamics and the recovery of culturally significant plants

“…In high-elevation subalpine forests that lack fire scars, contemporary fire-free intervals range from 100 to 350 years (Marcoux et al, 2013(Marcoux et al, , 2015. Across this elevational gradient, multiple studies highlight the influence of low-and mixed-severity fire regimes throughout dry forest ecosystems and the important contribution of Indigenous cultural burning (Copes-Gerbitz et al, 2023;Hessburg et al, 2019). Since the early 20th century, a provincial government focus on fire suppression and managing forests for timber values has led to a disruption of these historical fire regimes (Copes-Gerbitz et al, 2022).…”

“…Many fire scientists and land managers are now advocating the need to “restore fire‐resilient landscapes” (Hessburg et al, 2015), including through the restoration of historical fire regimes (Hagmann et al, 2021). Simultaneously, western‐trained scientists are increasingly recognizing the role of Indigenous cultural burning in shaping historical fire regimes (Copes‐Gerbitz et al, 2023) and associated biodiversity and ecosystem structure (Fletcher et al, 2021; Hoffman et al, 2021; Mariani et al, 2022).…”

Diffusion of indigenous fire management and carbon-credit programs: Opportunities and challenges for “scaling-up” to temperate ecosystems

“…The Chilcotin region encompasses a broad range of pyrophytic ecosystems, but is predominantly comprised of savanna-like grasslands, woodlands, and dry forests within the Bunchgrass (BG), Interior Douglas Fir (IDF), Sub-Boreal Pine-Spruce (SBPS), and Montane Spruce (MS) biogeoclimatic zones (Meidinger and Pojar, 1991). Historical fire regimes were variable across these biogeoclimatic zones, with frequent low-and moderate-severity surface fires dominating in the BG and IDF zones (Gayton, 2013;Harvey et al, 2017;Copes-Gerbitz et al, 2022), and a less frequent mix of low-to moderate-severity surface fires and high-severity crown fires dominating in the remaining zones (Cochrane, 2007;Marcoux et al, 2015). Many of these fire regimes were influenced by Indigenous fires (Turner, 1999;Harvey et al, 2017), which amplified fire frequencies and reduced severities relative to the background lightning-ignited wildfires (Copes-Gerbitz et al, 2022).…”

“…Historical fire regimes were variable across these biogeoclimatic zones, with frequent low-and moderate-severity surface fires dominating in the BG and IDF zones (Gayton, 2013;Harvey et al, 2017;Copes-Gerbitz et al, 2022), and a less frequent mix of low-to moderate-severity surface fires and high-severity crown fires dominating in the remaining zones (Cochrane, 2007;Marcoux et al, 2015). Many of these fire regimes were influenced by Indigenous fires (Turner, 1999;Harvey et al, 2017), which amplified fire frequencies and reduced severities relative to the background lightning-ignited wildfires (Copes-Gerbitz et al, 2022). The dominant plant species in this region are adapted to these historical fire regimes.…”

“…However, colonial fire exclusion through the forced relocation of Indigenous peoples onto reserves, and the prohibition of Indigenous burning, fundamentally altered the historical fire regimes and forests (Greene, 2021;Copes-Gerbitz et al, 2022). Several fire history reconstructions in central BC have documented the absence of low-to moderate-severity fires following colonization in the mid-to late-1800s, which altered forest structure and composition, leaving the landscape vulnerable to high severity fires (Harvey et al, 2017;Brookes et al, 2021;Copes-Gerbitz et al, 2022). Hence, revitalizing Indigenous fire practices offers an important landscape stewardship tool missing for almost a century .…”