Abstract: Sample plots were set up within the coniferous forests of Haizhai forestry, field surveys were conducted, surface litter was collected, and indoor combustion simulations and laboratory physical and chemical property analyses were performed, and SPSS 26.0 software was used to analyze the data to explore the characteristics of surface combustibles and potential fire behavior of the coniferous forests in Haizhai Forestry. Lanceolata had the worst combustibility as it had an absolute moisture content of (9.4±0.65)% and the lowest calorific value (19 878.9±48.63) kJ/kg, and also had the smallest fire intensity and rate of spread of (259.64±19.73) kW/m and (0.33±0.14) m/min, respectively. Pure forest of Pinus yunnanensis has a load of (0.27±0.12) kg/m2, a calorific value of (21 390.88±73.39) kJ/kg, a low fire intensity (307.26±15.83) kW/m, and an actual burn rate of only (55.32±15.02)%. Pure forest of Pinus yunnanensis has the highest calorific value and ignites easily, but the load is too low to sustain a normal burn. The calorific value of pure forest of Pinus huasanensis was lower than that of Pinus yunnanensis, and the fire intensity and burn rate were lower than those of mixed forest of Pinus yunnanensis-Pinus huasanensis. The spread rate and fire intensity of mixed forest of Pinus yunnanensis-Pinus huasanensis were (0.82±0.31) m/min and (564.14±13.53) kW/m, which were much higher than the other three species, and had the highest potential fire risk class. From the above potential fire behaviors, the risk level (from high to low) of the four types of coniferous forests in Haizhai Forestry to start a fire is mixed forest of Pinus yunnanensis-Pinus huasanensis, pure forest of Pinus huasanensis, pure forest of Pinus yunnanensis and lanceolata.

Key words: surface fuel, fire intensity, fire behavior, coniferous forest, Haizhai forestry