Effects of controlled burning on soil erosion rates, survival and growth of Pinus kesiya and Alnus japonica in Itogon, Benguet Province, Philippines

The effects of controlled burning on survival and growth of newly planted seedlings of Pinus insularis and Alnus japonica and soil erosion rates of the burned and unburned plots were quantified in Itogon, Benguet Province, Philippines. The results showed that survival of the two species in the burned and unburned plots was not significantly different. The overall mean survival rate of trees in the burned plot was 93.8% compared to 93.1% in the unburned. In terms of growth diameter as affected by fire, A. japonica diameter increment was higher in the low fire intensity, while for P insularis the diameter increment was higher in the unburned treatment compared to the two fire intensity levels. The same responses were also observed in the growth height of the two species. Soil erosion rate in 2008 was high in the burned plot at 2.73 tha(-1) and 0.73 tha(-1) for the unburned, while for 2009, the burned plot had 3.91 tha(-1) and 3.69 tha(-1) in the unburned. In terms of surface runoff, the unburned had higher value at 69.9 m(3)ha(-1) compared to 63.6 m(3)ha(-1) for the burned plot in 2008, but in 2009, the burned plot had higher surface runoff at 534.4 m(3)ha(-1) as against 529 m(3)ha(-1) in the unburned. While the cost of reforestation using controlled burning is much higher than the conventional reforestation approach, the use of fire to eradicate fire hazard is promising for ecosystems where fire is part of their natural development processes.