Abstract: The nonlinear relationship between forest fuel moisture and meteorological factors is an important
theoretical basis for the occurrence of forest fire and the prevention of fire. The moisture content of surface dead
fuel in three typical stands in Harbin urban city forestry demonstration base is taken as the object of study.
During the fall from September 2014 to November, the fixed two days are selected every week. The results
showed that the moisture content and meteorological factors of the combustible species in the three forest types of
Quercus mongolica, Juglans mandshurica, Betula platyphylla were studied from 8:00 to 18:00, and the dead
leaves, the 10 hr dead branches and the 1hr dead branches were selected to analyze nonlinear relationship
between moisture content and meteorological factors of materials, EXCEL 2013 and SPSS19. 0 are used on the
data for follow-up processing and correlation analysis. The results showed that: it was found that moisture of fuel
in the three forest types ranged from 14% to 67%; In the nonlinear model It is found that the correlation between
one hour ago and the current time is the highest that reaches 0. 89. In the nonlinear exponential model, the
model accuracy of Quercus mongolica and White birch was less than 15%. The accuracy of the model is better.

Key words: timelag, fuel moisture content,  meteorological factors, index model