Abstract: In this study,the Yuying and Fendou forest farms of Tuqiang Forest Bureau in Daxing'an Mountains were chosen as test areas,and their vegetation type,altitude,slop,aspect,and settlement buffer were selected as the main forest fire factors.The circumstances of forest fire risk were quantified by the factor-weights union method with the support of GIS.Four classes of forest fire risk ranging from low to extreme were generated.The none,low, moderate, high,and extremely high fire risk zones accounted for 0.37%, 0.63%, 38.67%,58.63% and 1.70%,respectively,which was in corresponding with normal distribution.About 60.33% of the test areas were predicted to be upper moderate risk zones,indicating that the forest fire management task in these areas is super onerous.There was an obvious regional difference in the distribution of forest fire risk zones,being higher in the center and lower around the center,and the difference in fire factors was also obvious.The GIS-based forest fire risk model of test areas strongly cohered with the actual fire-affected sites in 1987,which suggested that the forest fire risk zone mapping had a higher reliability,and could be used as the reference and guidance of forest fire management.

Key words: Winter wheat, Potassium fertilizer, Grain filling stage, Photosynthetic characteristics