大洋州各国/地区森林资源数据

联合国粮农组织(FAO)在“2005年世界森林资源评估”中,汇集了世界229个国家和地区的森林面积、森林蓄积以及森林覆盖率等数据,通过这些数据可以了解世界森林面积的变化情况。国家/地区2005(万年森hm林2)面积森林覆盖率(%)2面00积0年~2变00化5率年(森%林)森林蓄积(m3/hm2)美属萨

Advances in the Researches of Exterior Effect Factors on Tree Water Consumption

On summing up the present development of water consumption of trees,it showed that the exterior factors of water consumption consisted of two aspects.One was soil factors and the other was weather factors,including the intensity of the radiation,the temperature and relative atmosphere humidity.Commonly the rule of the two exterior factors of water consumption was obtained: first,when the water content of soil was more than the average content,stomata of leaves shut up within several hours,which led to the decrease of water consumption of trees.On the contrary,when the water content of soil was less than the average content,the result could lead to the decrease of water consumption of trees.Second,to some extents,with the increasing of the intensity of the radiation and the temperature,water consumption of trees increased.However,with the increasing of relative atmosphere humidity,water consumption of trees decreased.All this can provide evidence of following experiments about mechanisms of water consumption.Also,some problems of researching on exterior factors of water consumption of trees were pointed out.