Simulation of surface fire to study the spread rate of it's distribution in mixed hardwood forest

Wildfires as one of the natural events influence forest ecosystems. Global warming and it’s effect on lengthening of dry season along with accumulation of senesced litter may couple the effects of fire in forest ecosystems. Hyrcanian forests of Iran are often bothered from the natural and also manmade fires severely. The present study was conducted to investigate the spread rate of surface fire and the effective factors which influence on it in natural mixed forest of Chalmardi- Mazandaran، Northern Iran. The spread rate of fire was measured under different conditions which were simulated with different wind speed (1-16 m s-1)، slope classes (% 0-90)، species (Parrotia persica C. A. M.، Acer velutinum L.، Fagus orientalis L.، Carpinus betulus L.، Quercus castaneifolia L.) and thicknesses of leaf litter (1-8 cm). Results showed that the surface fire distributed intensively with increasing wind speed. This was also accelerated in greater slope degrees. Our findings revealed that the spread rate of fire increased with increasing litter thicknesses up to 4 cm and then decreased. The types of leaf litter influence the spread rate of fire، as leaves with small thickness (Fagus orientalis L.) and large width (Acer velutinum L.)، facilitate the fire transmission to neighbor litter by bending itself and increase the spread rate of fire، and leaves with greater (Quercus castaneifolia L.) and smaller (Carpinus betulus L.) thickness reduce the spread rate of fire due to the lack of rapid transmission of fire to the neighbor litter.