Abstract: [Objective] The assessment for forest combustion is a base of fire management. Simulation of the fire regime under different climate change scenarios with the burn probability model is an important way to understand the effects of climate change on fire activities. In this study, burning probability model (BURN-P3) was used to simulate the fire occurrence and spread on the landscape scale. The fire regime changes in Daxing'anling under four climate scenarios were described quantitatively based on the simulations with the burn probability model, which would facilitate understandings of the impacts of climate change and provide the scientific basis for fire management. [Method] The climate data simulated from the climate model for climate scenarios RCP2.6, RCP4.5, RCP6.0, and RCP8.5 were calibrated by using historical ground observations for temperature and precipitation. This paper simulated daily fire occurrence and spread in the Daxing'anling in 1971-2050 for four climate scenarios with the climate model data, fire weather index system and combustion probability model (BURN-P3). It was analyzed for the burn probability and fire behavior with the data of fuel type, fire occurence and terrain in the study area. [Result] The average burn probability for the whole study area in 1991-2010 (except 2003) was 0.010 8, and the average for fire scars 0.011 3. The average burn probability for the locations of fire occurrence was 0.012 45, which showed significant difference with the average for whole study area by t-test. In 2003, the average burn probability for the study area was 0.014 2, which 31.5% higher than that of 1991-2010. BURN-P3 model can be used in the study area for simulating fire regimes through comparative analysis for the simulation results and actually burned areas in history. Compared with the baseline period (1971-2000), the average combustion probability in 2021-2050 under climate scenarios RCP2.6, RCP4.5, RCP6.0, and RCP8.5 would increase -6.21%, 7.71%, 7.80%, and 19.48%, respectively. The increased areas were mainly distributed in the central and southern parts. Fire intensity would increase -13.0%, 4.4%, 1.5%, and 8.0% respectively. Meanwhile, the crown fraction burned would have an increase by -12.7%, 4.2%, 5.0%, and 4.7%, respectively. The central and western parts would have a significant increase.[Conclusion] The simulation results of BURN-P3 can reflect the status of forest burn probability in Daxing'anling. Compared to the baseline period (1971-2000), the average combustion probability in 2021-2050 under climate scenario RCP 2.6 would decrease, but it would increase under RCP4.5, RCP6.0 and RCP8.5. The average fire intensity, rate of spread and combustion probability would show a slight increase. The fire regime in central and western parts would have a significant increase.

Key words: climate change, burn probability, fire behavior