Lori Daniels, Professor of Forest Ecology, UBC- Vancouver, lori.daniels@ubc.ca 

Lori Daniels is a Professor of Forest Ecology in the Forest and Conservation Sciences Department at UBC-Vancouver. Lori directs the Tree-Ring Lab at UBC where her research team reconstructs historical fire regimes, plus the impacts of climate and humans on forest change. With her research team at UBC, Lori is researching wildfires and forest resilience to climate change in the interior BC, Rocky Mountain National Parks and foothills of Alberta.  

ABSTRACT

Title: Disrupted Fire Regimes in the Canadian Montane Forests

Authors: Lori D. Daniels and Greg A. Greene, Forest and Conservation Sciences Department, Faculty of Forestry, University of British Columbia, Vancouver, BC; lori.daniels@ubc.ca; map.n.trowel@gmail.com

Tree-ring reconstructions of historical fire frequency, severity, spatial variability, and extent, corroborated by other lines of evidence, are key for understanding fire regime drivers and the differences between historical and contemporary regimes. Here we show how new approaches build on traditional analyses of fire scars and forest age structures provide a deeper understanding of the role of wildfire in montane forests of British Columbia and the Canadian Rocky Mountain National Parks. Our fire history reconstructions show that historical fire regimes in montane forests of southeastern British Columbia were dominated by frequent lower-severity surface fires, that burned and scarred trees every 5 to 40 years for several centuries up to the 1900s. Despite the historical frequency of fires and recent periods of suitable climate, these forests last burned causing fire scars 40 to 160 years ago – providing strong evidence of the effects of disrupted fire regimes during the 20th century. The lack of recent fires is reflected in changes in tree composition and tree density. In absence of surface fires, dense understories of fire-intolerant trees persist, altering forest composition, structure and fuels. We show how the exclusion of indigenous cultural burning, followed by the cumulative effects of land-use change, early 19th century logging, even-aged silviculture, and fire suppression during the 20th century have altered the fire regimes and reduced the resilience of Canada’s montane forests.