Lethal soil heating during burning of masticated fuels: effects of soil moisture and texture

We developed a predictive model of soil temperature maxima during burning of masticated fuels. The model was well explained by three factors: soil moisture, soil depth, and fuel heat load. Soil texture, in contrast, was unrelated to the temperature profiles, suggesting a single model is applicable for all tested soils (pumice sand, loam, clay). Soil moisture as low as 20% by volume was sufficient to quench soil heating and inhibit the progression of lethal soil temperatures below the surface inch. Thus, burning of masticated fuels when soils are moist is recommended to avoid damaging roots and soil organisms.