Spatio-temporal Dynamics Of Forest Fuel Moisture Monitoring Using MODIS Data In Zhejiang Province

The forest fire is not only a very important but also an inevitable interference factor in natural ecosystem process, which changes the growth and development of plant and community, controls and adjusts the interaction between plants, affects the succession, biomass , productivity and biogeochemistry circulation of forest. From 1991 to 2006, the total forest-fire area of Zhejiang Province reached 90310 hm~2, which approximately accounts 1.63% of the entire forest area in Zhejiang Province, and the forest-fire area was 5645 hm~2 each year. With the aggravation of global change, both the frequency and the area of forest-fire have showed increasing trends.The water content or humidity of combustible materials in forest is the main index for forecasting fire behavior, energy liberation and estimating fire risk, and is the basis for determine prescribed burning and implementation fire in forest management. The humidity of combustible materials affects difficulty degree directly and affects fire intensity, fire behavior, fire spread speed and effective radiation, which has been paid attention by researchers as a key parameter for forest fire warming.This paper investigated environmental factors of forest and determinate moisture content of dead&live combustible materials brought back to laboratory taking evergreen broad-leaved forest ,masson pine forest, Chinese fir forest and bamboo forest as study objects which are common forest types in Zhejiang province. The result demonstrated that temperature is the highest, but the air humidity and the soil moisture are the lowest in masson forest, whose environment was most advantageous to causing forest fire. Four kind regression models about moisture content of dead combustible materials to environmental factors were established by applying the multivariate statistical analysis, all true coefficient R were bigger than 0.7, and results showed the precision of models were above73% after being tested. The regression model about humidity of live combustible materials in forest to MODIS normalized difference water index (NDWI)were established, which was retrieved on the live combustible materials in forest in whole province.The result showed that the precision was above 60%,and it could reflect humidity of combustible materials well, so it could provide key parameters for forest fire warning-forecast system established soon in Zhejiang Province.