Fuel Characteristics and Fire Behavior in Highland Corn Farm and Mixed Deciduous Forest at Nan Province
Pairin Palasak, Kobsak Wanthongchai, and San Kaitpraneet
Several highland areas in the Nan province have long been intensively applying slash and burn techniques for land preparation. However, fuel and fire information for slash and burn techniques is very limited. This research aimed to study the fuel characteristics and fire behavior in a highland corn farm and mixed deciduous forest located in the Na Noi district, Nan province. Each site consisted of 3 replication plots of 40 m × 40 m size each. Fuel characteristics (type, loads, and fuel residues) and fire behavior descriptors (rate of fire spread, flame length, and fire intensity) were evaluated. Burning experiments were carefully conducted in April 2017 under the watchful eye of forest fire guard officers. The results showed that the total fuel load in the corn farm (3.86 t ha-1) was higher than in the mixed deciduous forest (3.57 t ha-1). The total residues (ash, charred, and unburned materials) left after burning in the corn farm and mixed deciduous forest were 0.25 and 0.35 t ha-1, respectively. The total fuel consumed by fire, therefore, was 3.61 and 3.22 t ha-1, for the corn farm and mixed deciduous forest, respectively. The rate of fire spread was 5.61 m min-1 in the corn farm, and 4.68 m min-1 in the mixed deciduous forest, though the numbers were not significantly different (p>0.05). Burning intensity was classified as medium in both the corn farm (562.06 kW m-1) and mixed deciduous forest (463.83 kW m-1) . The results could be applied in fire management during the selection of appropriate methodologies, tools, and the number of officers.