Study On The Dynamics Of Forest Fire Weather In Tahe County Of Great Xing'an Mountains Region, Heilongjiang Province

Based on the forest fire and meteorological data from 1974 to 2008 in Tahe County of Great Xing'an Mountains region, the dynamics of forest fire weather indices were analyzed quantitatively and qualitatively for the study region with the help of Canadian Forest Fire Weather Index System (CFFWIS). Our results indicated that:The average of annual fire occurrence showed an increasing pattern for the period 1974-2008 and the average of annual fire occurrence during the period 2000-2008 had increased by 72.2% compared to the period 1974-1999. By the impact of climate change, more forest fires occurred in the summer fire season around the study region. Especially since 2000, the annual forest fire numbers have a significant increase in the summer fire season, which increase by 5.9 times during the period 2000-2008 compared to that during the period 1974-1999. The trends of fuel moisture codes, fire behavior indices and fire severity indices were significantly increasing for the period 1974-2008, and these trends were also getting more evident as time goes by. For example, annual FFMC, DMC, DC, BUI, FWI and SSR values during the period 2000-2008 increased by 2.5%,35.0%,17.2%,34.6%,22.7% and 28.4% compared to the period 1990-1999, annual FFMC, DMC, DC, BUI, FWI and SSR values during the period 2005-2008 increased by 5.5%,38.7%,28.9%,40.4%,33.6% and 38.2% compared to the period 2000-2004. The probability of forest fire occurrence would increase significantly, fuels would get drier, fire intensity would increase, fire control would be more difficult and fire weather would be more serious. More efforts should be made in order to increase forest fire control ability in the future, especially in the extended summer fire season. Prescribed burning, as a fundamental technique, should be applied to reduce fuel load to reduce the probability of fire occurrence and fire potential intensity...