森林衰退与全球气候变化

FOREST DECLINE AND THE GLOBAL CLIMATE CHANGE

工业革命以来的人类活动，改变着大气的化学组成，从而改变着全球的气候。气候变率影响着森林的生长，甚至能导致森林衰退。全球气候变化引起森林衰退的机制可能有几种。全球变暖、降水模型的改变以及蒸散作用的提高，将给一些森林带来高温胁迫和水分胁迫，危害植物的生理过程。ＣＯ＿２的施肥作用及其与气温升高的协同效应，将促进植物的新陈代谢，加速树木的成熟和衰老。在全球气候变化条件下，植物种竞争和分异将加强，气候变率和极端气候干扰将增加，因而森林生态系统将更易发生涨落。

ince the industrial revolution,the anthropogenic activities have been changing thechemical compositions of the atmosphere,and hence have been changing the global climate.Many studies showed that climate change could influence the growth of forests,and evencould result in forest decline.There would be several possible mechanisms in forest declineinduced by the global climate change. The global warming,precipitation pattern change andevapotranspiration enhancement would bring heat stress and water stress to some forests,which might be detrimental to plant physiological processes.The CO_2 fertilization and its co-operation with the rising atmospheric temperature would promote the metabolism in plants,and accelerate the mature and senescence of trees.Under the condition of the global climatechange,the competition and differentiation between plant species would be strengthened,cli-matic variability and extreme climatic disturbance would be increased,and therefore forestecosvstems would be easier to fall into fluctuation.