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欧州以针叶林为主,其中欧州松的比重较大,这种林分具有高度的易燃性,因松林含有易燃的树脂,挥发油等,助长了大火灾的发生。此外,松林的地被物,包括杂草、苔藓、芦丛和灌木丛,也极易燃烧。火灾的发生,在松林幼令至林令为40年的阶段中,蔓延特别快。在混交林中,火险级的高低与松树在林分中所占的比重和地被物类型有密切关系;在阔叶林中,与地被物的类型关系不大。瑞典、联邦德国、民主德国、白俄罗斯、俄罗斯联邦地区的森林,具有以下三个特点;①在林分的树种组成中,松树占有很大的百分比;②在林分中,幼令林比重大;③森林的火险级高。
The coniferous forest is the dominant species in Europe, with the greater proportion of Pinus massoniana, which has a high degree of flammability. The pine forests contain flammable resins and volatile oil, contributing to the occurrence of a major fire. In addition, the pine coverings, including weeds, moss, reeds and bushes, are also extremely flammable. The fire broke out especially rapidly during the 40-year period from the young pineling to the pine forest in Songlin. In the mixed forest, the level of fire danger is closely related to the proportion of pine trees in the forest stand and the types of ground cover; in the broad-leaved forest, it is not related to the type of ground cover. Sweden, the Federal Republic of Germany, the Democratic Republic of Germany, Belarus and the Russian Federation have the following three characteristics: (1) Pine trees account for a large percentage of the tree species in the stands; (2) ③ forest fire level high.