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引言森林是一个具有正运转着的生物群体复杂“社会”机构的生物群落。树木在保持水土方面可发挥决定性的作用。它们从土地吸收水分,并通过蒸腾压把水释放到大气中,由于大气中水汽的冷凝再以降水形式回归大地,这种作用持续地循环着。在生态系标准上,低剂量污染条件下,生态系内的植被和土壤有明显减弱空气污染的功能。当受到中等程度污染剂量时,个别树种或特定树种的个别成员可能会敏感,由于营养恶化、新陈代谢减弱,易遭受害虫或病害的侵袭,或者
Introduction Forests are a biome that has a complex “social” institution with a functioning biological community. Trees can play a decisive role in maintaining soil and water. They absorb moisture from the land and release it into the atmosphere by transpiration, which circulates continuously as the water vapor in the atmosphere condenses and returns to the earth in the form of precipitation. In the ecosystem standards, low-dose pollution, vegetation and soil within the ecosystem significantly reduce the function of air pollution. Individual species, or individual members of a particular tree species, may be susceptible to moderate levels of pollution, deteriorate due to deterioration in nutrition, diminish metabolism, are susceptible to pests or disease, or