古炭屑与古森林火?

森林火普遍发生在地质历史时期中，它对自然植被系统的演替起着重要作用。不同强度和频率的森林火培育出不同类型的植被：频繁的森林火导致草甸的形成，而热带雨林形成的原因之一是森林火的缺乏。古炭屑作为古森林火的遗迹，具有分布广泛、细胞结构保存完好以及原地埋藏等特点，为研究古森林火发生的强度和频率提供了宝贵的材料。古炭屑的出现与当时的气候因素、植被类型和地理状况有密切关系：干旱、少雨的气候常常伴随高频率森林火的发生，表现出古炭屑的数量增多；易燃物种组成的植被易发生森林火，古炭屑的出现也会增多，而耐火树种会降低森林火的强度，古炭屑则出现少。因此，从古炭屑的数量和种类的变化，可探讨古森林火的发生规律，进而推断长期地质历史时期的气候、植被、地理状况的演变。

FOSSIL CHARCOAL AND ANCIENT FOREST FIRE

The forest-fire is a special composition in the natural ecosystem. It could be triggered by different factors repeatedly. The frequency and intensity of its occurrence depended on the behaviors of eco-factors, the forest-fire, however, affected the environmental events deeply on the contrary. It takes an important part in the development of vegetation system, i.e. a special kind of frequency and intensity of the forest fire are helpful to develop a special vegetation type, the higher frequency could lead to the formation of grass marshland and tropical rainforest could develop if without the influence of forest-fire. The forest fire happened universally in geology history and left a lot of remains. The fossil charcoal was one of the remains. The charcoal distributed widely and the cell structure was preserved very well when being covered by earth. Furthermore, the fossil charcoal provided more important information of the frequency and intensity of ancient forest-fire without any artificial interfering factor. The amount of fossil charcoal showed close relation to the climate factor, vegetation type and geographical features. The arid climate such as short of rainfall or the vegetation composed of combustible species of plants could raise the frequency of forest fire, the amount of fossil charcoal would increased; whereas wet climate and the vegetation with apyrous species led the amount decrease. Besides, terrestrial environment is favorable to induce the occurring of forest fire. The important rule of forest-fire is helpful to conjecture the development of climate, vegetation and geographical features in long historical period. The fossil charcoal, not only provided the important evidence of paleoflora, palaeobiotope and palaeogeography, but provided an important measure to use forest fire in improving the ecological environment also. The research on the fossil charcoal offers the chance to understand palaeoecology, palaeoclimatology and palaeogeography and lay the theory basis of using forest fire and improving nature environment, because under various conditions, presented or controlled burning is used to maintain or develop grassland, shrub-land or forest.