Comparing modeled soil temperature and moisture dynamics during prescribed fires, slash-pile burns and wildfires

Background Wildfires, prescribed fires and slash-pile burns are disturbances that occur in many terrestrial ecosystems. Such fires produce variable surface heat fluxes causing a spectrum of effects on soil, such as seed mortality, nutrient loss, changes in microbial activity and water repellency. Accurately modeling soil heating is vital to predicting these second-order fire effects. The process-based Massman HMV (Heat–Moisture–Vapor) model incorporates soil water evaporation, heat transport and water vapor movement, and captures the observed rapid evaporation of soil moisture. Aims Improve the Massman HMV model and compare it with Campbell soil heating model using four independent soil temperature datasets collected during burning. Methods The models were evaluated using similar BFD curves against observed temperature and soil moisture using standard statistical methods. Key results Results suggest reasonable agreement between the Massman HMV model and field soil temperature data under various burn scenarios and it was consistently more accurate than the Campbell model. Conclusions The Massman HMV model improved soil heating predictions and provided soil moisture predictions. Implications The Massman HMV model was incorporated in the First Order Fire Effects Model (FOFEM ver. 6.7) with a user-friendly interface that allows managers to assess the heating impacts of fire on soil temperature and moisture.