ESR2 Project

Fuel (vegetation) moisture content varies across a range of spatial scales and is affected by different environmental factors across these scales. Understanding and capturing this variability is important for predicting wildfire behaviour, including ignition probability and rate of spread, and is an important component of fire danger rating systems. Differences in canopy coverage, elevation, aspect and soil properties all modify the micrometeorological drivers of fuel moisture content. This spatial complexity has meant that fuel moisture, and therefore fire danger rating systems, have generally been considered at a large spatial scale, where climate and fuel type are the main drivers of variation, and regional danger ratings are then interpreted locally by experienced fire personnel. However, given the complexity of landscapes in England, fuel moisture content could be expected to vary significantly over local landscapes and be affected by landscape variables that are masked by sampling at a national level. There is a need to develop our understanding of plot-scale fuel moisture dynamics, particularly for temperate fuels in traditionally ‘low-fire’ countries.

In this research, I ask if it is important to account for local landscape fuel moisture content variability, to inform ongoing efforts to develop fire danger rating systems for the UK and north western Europe. Live and dead Calluna vulgaris fine fuel moisture content will be measured across landscape variables hypothesised to be important controls on fuel moisture content in order to answer the following research questions: (1) what is the nature of wildfire in England? (2) What is the magnitude of variability in local landscape fuel moisture content, and is it important? (3) What controls local landscape differences in fuel moisture content? (4) Can we develop a fire weather index that accounts for local landscape fuel moisture content variability? This also opens opportunities to validate fire behaviour models to better capture these relationships between local landscape controls and plot-scale fuel moisture content variation. Ultimately, the outputs from this research will facilitate improvements in the predictability of fuel moisture and wildfire behaviour and the development of a fire weather index and danger rating system specific to temperate fuels, to inform fire service resourcing and managed burn decisions.