Open Collections

Baron, Jennifer Nicole

University of British Columbia

Prior to North American colonization, landscapes were governed by system-level feedbacks that maintained ecological resilience to disturbance. Increasingly frequent and extreme wildfire seasons in British Columbia (BC), Canada, are a symptom of the landscape-level disruption of historical fire regimes. Through three interrelated research questions, this dissertation characterizes the landscape-level disruption of fire regimes in southeastern BC and the ability of existing research and management systems to address these changes. Chapter 3 identifies transitions in historical fire regimes, describes the factors that drove them, and quantifies the resulting departures in fire frequency. I find that fire exclusion has significantly disrupted pre-colonial fire regimes, which transitioned through three phases from 1919 to 2019 to create fire deficits of 1–10 fires missed across forest types. Chapter 4 quantifies the accuracy and applicability of fuel type maps, explores the consequences of fuel misclassification, and identifies pathways to improve fuel representations. I find that fuel type maps do not accurately represent extant fuelbeds, particularly in dry interior ecosystems, mixedwood and deciduous stands, and post-harvesting conditions. Fuel typing mismatches stemmed from the low accuracy and availability of forest inventory data and the low applicability of existing fuel types. Chapter 5 assesses the state of landscape-fire-succession simulation modelling in North America and characterizes approaches on the frontier of this domain. I find that while succession is frequently represented as a complex mechanistic process, fire is often represented as a simplified hybrid process, leading to five common challenges and related priorities for next-generation development. Through this dissertation, three collective insights emerge: (1) The disruption of historical fire regimes has altered landscapes and degraded ecological resilience, exposing social-ecological systems to the threat of severe wildfires. (2) Adaptive management interventions that restore ecological resilience by reintroducing the role of fire as a process are justified to restabilize landscape dynamics. (3) Managing altered fire regime will require data and modelling systems evolve in their ability to represent fuels and fire-vegetation dynamics. Ultimately, transformative changes to systems and management are warranted to address the extent of fire regime departures and alter the current trajectory of landscapes as the climate steadily warms.

Text

2025-01-27

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/90212

Forestry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/