MICHAEL C. OHMAN
Invasion of grasslands by woody shrubs can alter existing fire regimes and give rise to problem fire behavior. Invaded areas are likely to burn less often but with more intensity. Abandoned pastures on Naushon Island, Massachusetts (USA) which have been invaded by the woody vine Smilax rotundifolia follow this pattern. I evaluated the usefulness of standard and custom fuel models for predicting fire behavior observed in a 0.5-acre (0.2-ha) experimental burn. Custom fuel model development required characterizing fuel load and fuel bed depth of the experimental burn plot – a task complicated a dense mat of vines with 100 % cover to a height of 3 to 6 ft (1 to 2 m). This was done by measuring the height of fuel beds, estimating 3-dimensional cover by modified point-intercept sampling, and harvesting live vines and leaves and dead woody and non-woody litter and vines from 1 m2 cubes. From these data, I developed regression equations to estimate fuel load using fuel bed depth.