| The majority in forest fires reports during these years are mildly combusted and not be burned to the main trunks of trees.Therefore,researching in flammability of trees is currently basing on leaves and small branches.And few making concrete conclusion in the use of plant physicochemical properties and biological,ecological characteristics and other indicators to analyze the flammability of the tree species,and cone calorimeter has many test parameters,experimental results and samples in actual situation with many more similar performance.Four common conifers were chosen in this essay.Pinus tabuliformis,Platycladus orientalis,Cunninghamia lanceolata,and Pinus massniana in North China region have a diameter of 0.5 cm to 1.5 cm.Fresh branches were in experiments.The results tell that litters are more flammable than fresh leaves by comparing the weight loss curves from different combustibles in the same species.The heat releasing rate of Chinese fir leaves is 209 KW m-2 comparing the flammability of different species.-1,the total heat releasing is 11.1 MJ·m-2.which is the largest among these 4 leaves and the shortest ignition time.Therefore,the conifer trees of the Chinese fir are the most flammable with the worst fire resistance,like Thuja orientalis,Pinus massoniana and Pinus tabulaeformis.Comparatively,the heat releasing rate of masson pine was 229 KW m-2s-1,the total heat releasing was 74.9 MJ m-2,and the heat release rate of Chinese pine was 189 KW.·m-2s-1,total heat releasing is 76.8 MJ·m-2,indicating that the two kinds of conifers have poor fire resistance;comparing with the law of smoke release,the total amount of total smoke released from Pinus massoniana was found to be 449 MJ·m-2.The Masson pine branch was 540 MJ·m-2,with the largest peak of extinction area and more than 800 m2·kg-1 of branches and leaves,which also indicated the severity of its combustion reaction.The study also found that the content of CO released from the combustion of Chinese fir is the highest. |
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