The relationship between sap flow of intercropped young poplar trees (Populus×euramericana cv. N3016) and environmental factors in a semiarid region of northeastern China |
| |
Authors: | De‐Xin Guan Xiao‐Jing Zhang Feng‐Hui Yuan Ni‐Na Chen An‐Zhi Wang Jia‐Bing Wu Chang‐Jie Jin |
| |
Institution: | 1. State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, , Shenyang, 110016 PR China;2. Graduate University of Chinese Academy of Sciences, , Beijing, 100049 PR China |
| |
Abstract: | Estimating transpiration of the trees in agroforestry system is important in water management of the site. Sap flow of intercropped fast‐growing young poplar trees and microclimate factors in semiarid northeastern China was measured in two growing seasons (2008 and 2009). Sapwood growth and water storage of wood and leaf increment during the growing season were involved in the calculation of sap flow. The results showed that diurnal variation of sap flow followed to that of short wave solar radiation. Sap flows both in 10 min mean and daily gross values mainly depended on solar radiation and vapor pressure deficit, and the relations well fit hyperbolic function. The regression coefficients of monthly window data indicated that the seasonal variation of sap flow capacities decreased gradually from June to September. Moderate soil water stress of upper soil layer (0–50 cm) did not constrain the sap flow because the trees could use the water at deeper soil layer. The daily sap flow per tree ranged 0.8 to 18.1 and 3.7 to 23.8 kg d?1 tree?1, with averages of 8.7 and 14.3 kg d?1 tree?1 in 2008 and 2009 respectively. An empirical model was established to estimate the sap flow of the poplar trees by solar radiation, vapor pressure deficit, leaf area index and Julian days. Copyright © 2011 John Wiley & Sons, Ltd. |
| |
Keywords: | sap flow young poplar trees seasonal variation semiarid region |
|
|