Abstract:

Abstract： Fire behavior and fuel loading changes were investigated in plots of two burned, occurred in spring of 2007, slashes in Daxingan Mountains. We used Canadian fire weather index (FWI) system to analysis fire danger changes in that period. A linear intersect method was used for assessing ground fuel loadings and the MODIS satellite data were used for burn classification. The results indicated that the indexes of FWI system were a good indicator for fire danger rating in Daxing'an Mountains. Most fine fuel moisture codes (FFMC) were more than 90 during April and May of 2007, and duff moisture code (DMC) and drought code (DC) were rising continually in April. The two fires occurred in high fire danger period. In Danxing'an Mountains most fires were surface fire, and some areas had torching fire. For broadleaf forests ground diameter fuels didnt increase significantly after fire, but all diameter fuels increased in coniferous and broadleaf mixed forests except 50～699 cm diameter fuels. Fire intensity had an influence on ground fuel loadings. After the fire with modest and high fire intensity the grass coverage decreased significantly and had a high mortality rate of understory. The areas with high fire intensity of the two fires were accounted for 332% and 464% of the burnedarea respectively.

Key words: Key words： consumed fuel, forest fire danger rating, fire behavior, Daxing'an Mountains