Study On The Impacts Of Climate Change On Forest Fires And The Evaluation Of The FWI System Application In The Zhejiang Province

After extensively collecting meteorological data and forest fire data of Zhejiang Province, the changes of weather index which are closely correlated with forest fires during 1956～2006, the changes of forest fire weather index and the changes of fire regime during 1991～2006 have been studied. The impacts of climate change on forest fires were studied from Forest Weather Index system. The fire danger classification method and evaluation of FWI system application in Zhejiang Province have been studied.The results show that the climate of Zhejiang forest region was more favorable to forest fire occurrence than before during 1956～2006. Annual temperature average has increased significantly during 1956～2006. Annual precipitation showed a tendency to rise during studied time period. The annual wind speed and the annual relative humidity average decreased markedly. It was inferred that the climate of Zhejiang forest region changed for warming and drying. The annual relative humidity average decreased slowly in the precipitation increased period, and decreased markedly in the precipitation decreased period.Because the climate of Zhejiang forest region has changed for drying and warming, the fire weather severity rose during 1956～2006. The fire weather index FFMC(Fine Fuel Moisture Code) which represents fire ignition, the fire weather indexes DMC(Duff Moisture Code), DC(Drought Code) and BUI(Build-up Index) which represent the fuel moisture, and the fire weather index FWI(Fire Weather Index)which represents intensity of the spreading fire increased significantly in working and non-working fire season during 1956-2006. It was indicated that the fire fuel in Zhejiang region had a tendency to become dryer and energy rate of the speeding fire had a tendency to increase. This could induce fire intensity and forest fire to increase, especially in the non-working fire season.The FWI classes of fire danger were reassessed for conditions found in Zhejiang Province based on the comparison of the values found on fires from 17 meteorological stations during 1956～2006. The FWI system was ranged for low, moderate, high, very high and extreme high. It was indicated that FWI system has good evaluation in Zhejiang Province.In a word, FWI system has good evaluation in Zhejiang Province. Under the global warming, the climate of Zhejiang forest region has evolved to warming and drying during 1956～2006, which was more favorable to forest fire occurrence than before. In the future the climate continues warming, so the forest fire weather severity in Zhejiang forest region will become severer.