Multi-scale drivers of wildfire danger in temperate Europe

Little, Kerryn Elizabeth ORCID: 0000-0002-8303-5297 (2024). Multi-scale drivers of wildfire danger in temperate Europe. University of Birmingham. Ph.D.

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Abstract

Wildfire danger is increasing within temperate ecosystems that have not historically been prone to extreme wildfires. To date, assessments of wildfire danger have typically been constrained to coarse spatial scales using systems that were developed within traditionally fire prone regions. However, the processes controlling wildfire danger operate across spatiotemporal scales, supporting the need for a more holistic approach to assessing wildfire danger that recognises the multi-scale requirements of different decision-making needs. An understanding of the underlying controls on components of wildfire danger is especially needed in understudied, emerging fire prone landscapes like the peatlands and heathlands of temperate Europe, where fine-scale heterogeneity can be important for wildfire danger and fuels differ to those in traditionally fire prone landscapes.
This PhD thesis examined the multi-scale drivers of wildfire danger in temperate Europe at the synoptic, landscape, and plot scales through four research papers, finding: (1) Europe-wide, extreme fire weather and wildfires are more likely to occur during persistent, anomalous atmospheric blocking. (2) Fuel moisture content is highly variable at the landscape level, creating on/off thresholding of live fuel availability for wildfire spread and vulnerability of the organic layer to smouldering combustion associated with landscape controls. (3) This cross-landscape fuel moisture variability significantly impacts simulated wildfire behaviour. (4) Among-sampler variability is a relevant source of measurement error in fuel moisture campaigns that is important to consider and account for to isolate fuel moisture dynamics at broad spatial scales.
This PhD thesis contributes to our understanding of the multi-scale processes controlling wildfire danger in temperate ecosystems by demonstrating that weather patterns at large spatial extents have a key impact on wildfire occurrence and surface fire weather in the synoptic temporal range. However, there is a clear need to understand landscape-level fuel moisture dynamics that are masked using current regional estimates. This is shown to be relevant for improving fire behaviour predictions in the dominant fuel types in temperate fire prone ecosystems by indicating that fire behaviour models are sensitive to fine-scale landscape fuel moisture variability. Finally, in a drive to scale-up fuel moisture field campaigns using measurements collected from different samplers, it has been possible to isolate the likely measurement error within intensive fuel measurement campaigns that are essential for understanding spatiotemporal fuel moisture dynamics. The results of this thesis have implications for wildfire preparedness, land and fire management decision-making, embedding citizen science into wildfire research, and understanding future wildfire risk. A holistic approach to wildfire danger research will ultimately allow for the development of fuel models, fire behaviour models, and wildfire danger rating systems that meet the diversity of decision-making needs and spatial complexity of wildfire danger both in temperate emerging fire prone regions and beyond.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):