Poplar plantation has the potential to alter the water balance in semiarid Inner Mongolia.
Poplar plantation is the most dominant broadleaf forest type in northern China. Since the mid-1990s plantation was intensified to combat desertification along China's northwestern border, i.e., within Inner Mongolia (IM). This evoked much concern regarding the ecological and environmental effects on areas that naturally grow grass or shrub vegetation. To highlight potential consequences of large-scale poplar plantations on the water budget within semiarid IM, we compared the growing season water balance (evapotranspiration (ET) and precipitation (PPT)) of a 3-yr old poplar plantation (Kp(3)) and a natural shrubland (Ks) in the Kubuqi Desert in western IM, and a 6-yr old poplar plantation (Bp(6)) growing under sub-humid climate near Beijing. The results showed that, despite 33% lower PPT at Kp(3), ET was 2% higher at Kp(3) (228 mm) as compared with Ks (223 mm) in May-September 2006. The difference derived mainly from higher ET at the plantation during drier periods of the growing season, which also indicated that the poplars must have partly transpired groundwater. Estimated growing season ET at Bp(6) was about 550 mm and more than 100% higher than at Kp(3). It is estimated that increases in leaf area index and net radiation at Kp(3) provide future potential for the poplars in Kubuqi to exceed the present ET and ET of the natural shrubland by 100-200%. These increases in ET are only possible through the permanent use of groundwater either directly by the trees or through increased irrigation. This may significantly change the water balance in the area (e.g., high ET at the cost of a reduction in the water table), which renders large-scale plantations a questionable tool in sustainable arid-land management.
Department of Environmental Sciences, The University of Toledo, Toledo, OH 43606, USA. Burkhard.Wilske@utoledo.edu
Burkhard
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Wilske
Nan
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Lu
Long
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Wei
Shiping
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Chen
Tonggang
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Zha
Chenfeng
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Liu
Wenting
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Xu
Asko
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Noormets
Jianhui
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Huang
Yafen
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Wei
Jun
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Chen
Zhiqiang
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Zhang
Jian
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Ge
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Sun
Kirk
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Guo
Steve
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McNulty
Ranjeet
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John
Xingguo
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Han
Guanghui
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Lin
Jiquan
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Chen
D002681:China; D002980:Climate; D017753:Ecosystem; D018526:Plant Transpiration / Q000502:physiology; D032107:Populus / Q000378:metabolism*; D014872:Water Movements