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| Water consumption of forests in project area of returning farmland to forests in Datong county, Qinhai province |
| Chang Guoliang 1, Zhao Wanqi 2, He Kangning 1, Shi Changqing 1 |
| 1.College of soil and Water Conservation,Beijing Forestry university, Key Laboratory of Soil and Water Conservation and Desertification Combating of MOE, 100083,Beijing; 2.Datong Forestry Tourism Bureau of Qinghai,810100,Datong, Qinghai:China |
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Abstract In order to provide proof for tree species selection in returning farmland to forest project, based on Penman-Monteith equation and oriented flux method, the paper has studied the seasonal changes of water consumption of forests in 2002 and 2003.The studied tree species are Picea crassifolia, Picea purpurea, Larix principis-rupprechtii, Betula platyphylla, Populus cathayana, Hippophae rhamnoides, which were planted for returning farmland into forests since early 1980s. It was concluded that: The month avenge relative error of two calculating stands evapotranspiration methods is 5.7%. The total evapotranspiration of middle stand of mixed forests composed of Populus cathayana with Hippophae rhamnoides,pure forest of Betula platyphylla, mixed forest of Populus cathayana with shrubs, mixed forest of Betula platyphylla with Picea crassifolia and Hippophae rhamnoides is 488～538mm, the total evaporation accounting for 74%～79% of total evapotranspiration, the total vaporation is 10%～12% of that and no surface runoff. However, the avenge total evapotranspiration of young aged stands of pure forest of Picea purpurea, Populus cathayana, Larix principis-rupprechtii, mixed forests composed of Picea crassifolia is 450～510mm, the total evaporation accounting for 45%～69% of total evapotranspiration, the total evaporation is 16%～44% of that and a surface runoff is 1%～6% of precipitation. The transpiration of the most stands in the period from June to August accounts for 80% of that in total year.
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Received: 09 April 2004
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