The climate space of fire regimes in north‐western North America

Abstract

Aim Studies of fire activity along environmental gradients have been undertaken, but the results of such studies have yet to be integrated with fire-regime analysis. We characterize fire-regime components along climate gradients and a gradient of human influence.Location We focus on a climatically diverse region of north-western North America extending from northern British Columbia, Canada, to northern Utah and Colorado, USA.Methods We used a multivariate framework to collapse 12 climatic variables into two major climate gradients and binned them into 73 discrete climate domains. We examined variation in fire-regime components (frequency, size, severity, seasonality and cause) across climate domains. Fire-regime attributes were compiled from existing databases and Landsat imagery for 1897 large fires. Relationships among the fire-regime components, climate gradients and human influence were examined through bivariate regressions. The unique contribution of human influence was also assessed.Results A primary climate gradient of temperature and summer precipitation and a secondary gradient of continentality and winter precipitation in the study area were identified. Fire occupied a distinct central region of such climate space, within which fire-regime components varied considerably. We identified significant interrelations between fire-regime components of fire size, frequency, burn severity and cause. The influence of humans was apparent in patterns of burn severity and ignition cause.Main conclusions Wildfire activity is highest where thermal and moisture gradients converge to promote fuel production, flammability and ignitions. Having linked fire-regime components to large-scale climate gradients, we show that fire regimes -like the climate that controls them -are a part of a continuum, expanding on models of varying constraints on fire activity. The observed relationships between fire-regime components, together with the distinct role of climatic and human influences, generate variation in biotic communities. Thus, future changes to climate may lead to ecological changes through altered fire regimes.

Mean Composite Fire Severity Metrics Computed with Google Earth Engine Offer Improved Accuracy and Expanded Mapping Potential

“…The Monitoring Trends in Burn Severity (MTBS) program in the US, which produces and distributes Landsat-based fire severity datasets [19], has enabled scientists to conduct research involving hundreds to thousands of fires [2,24,40,41]. Outside of the US, where programs similar to MTBS do not exist, most fire severity research is limited to only a handful of fires, the exceptions being Fang et al [15] (n = 72 fires in China) and Whitman et al [42] (n = 56 fires in Canada). We suggest that the GEE methodology we developed will allow users in regions outside of the US to efficiently produce fire severity datasets for hundreds to thousands of fires in their geographic areas of interest, thereby providing enhanced opportunities for fire severity monitoring and research.…”

Seven hundred years of human-driven and climate-influenced fire activity in a British Columbia coastal temperate rainforest

“…Drivers of historic fire activity remain largely unknown in coastal temperate rainforests in the PNW of North America [1,4,59]. We present the first examination of the influences of and interrelationships between humans and climate on fire activity in a very wet coastal temperate rainforest using a ca 700-year record of fire scars and stand establishment.…”

Fire Regimes and Their Drivers in the Upper Guinean Region of West Africa

“…The complex interactions of ignition sources with vegetation, climate, and topography give rise to fire regimes, an ecological concept describing the range of fire characteristics occurring at a given geographic location and time period [1,2]. Fire regimes can be characterized by various metrics, including fire size, seasonality, frequency, intensity, and severity.…”