Experimental Study On Flammability Of Ground Litter In 6 Major Forest Types In Changbai Mountain

For forests,fires are one of the major disasters.Forest combustibles,as the material basis for forest burning,constitute the main body of forest fire behavior and the primary condition for forest fires to occur.Among them,litter on the ground is an important part of forest combustibles.The plant species of Changbai Mountain in Jilin Province is very rich.Due to climate warming and other reasons,under the influence of long-term dry and early climate conditions,the fire hazards in Changbai Mountain have been increasing year by year.In this paper,the surface litter of 6 major forest types in Huangsongpu Forest Farm of Changbai Mountain is selected as the research object.Pyrolysis and combustion experiments are performed to comprehensively analyze the flammability of the forest.The aim is to provide a theoretical reference for the effective prevention and control of forest fires in Changbai Mountain and enrich the forest combustibility The research work on the combustibility of materials and the establishment of forest fire prediction models provide basic data.Pyrolysis experiments were performed on the main types of forest litter in Huangsongpu Forest Farm of Changbai Mountain.The pyrolysis characteristics were analyzed,and the effects of different experimental conditions on the pyrolysis performance of surface litters were studied.The experimental results show that the pyrolysis process of each sample includes 4 stages.The weightlessness rate of the main weightlessness phase is the largest,accounting for 45.31?61.81%of the entire pyrolysis process;,The greater the weight loss rate of the sample,the more adequate the pyrolysis;when the particle size is 178-250?m,the sample pyrolysis reaction is the best;the pyrolysis process of the sample in the air atmosphere has more weight loss rate,mixed coniferous forest,mixed coniferous and broad forest,larch forest,broad-leaved mixed forest,poplar forest.The Gorbatchev integral method was used to analyze the dynamics of the litter on the ground,establish a pyrolysis kinetic model and calculate the kinetic parameters.It can be obtained that the order of its activation energy is consistent with its flammability and flammability.Among them,the activation of the litter on the surface of the birch forest The maximum energy is 95.5kj·mol-1,and the smallest is 68.8kj·mol-1.The self-designed combustion experimental device was used to perform a combustion experiment on the litter on the ground.The experimental results show that the order of the fire intensity of the litter on the ground is consistent with its flammability and activation energy.The fire intensity of the birch forest is the largest,which is 460.23kW·m-1.The fire intensity of poplar forest is the smallest,which is 367.09kW·m-1;the greater the wind speed,the faster the fire spreads;the wind speed has the greatest impact on the surface litter of birch forest,and has the least impact on poplar forest;when the wind speed is too large or too high Hours,combustibles cannot be completely burned out.When the wind speed is 6m·s-1,the average temperature during the combustion process is the highest,and the burning rate is the highest.When going uphill,the greater the slope,the greater the fire spreading speed,and the lower the burning rate.In the case of a slope fire,the larger the slope,the greater the burning rate,and the lower the speed of fire spread.