Skip to page content
USDA Forest Service
  
Treesearch

Research & Development Treesearch

 
Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Northern
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help
 

Science.gov - We Participate


USA.gov  Government Made Easy


Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.
20090-6090

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (3.5 MB)

Title: Hydraulic lift in a neotropical savanna: experimental manipulation and model simulations

Author: Scholz, Fabian G.; Bucci, Sandra J.; Hoffmann, William A.; Meinzer, Frederick C.; Goldstein, Guillermo;

Date: 2010

Source: Agricultural and Forest Meteorology. 150: 629-639

Publication Series: Scientific Journal (JRNL)

Description: The objective of this study was to assess the magnitude of hydraulic lift in Brazilian savannas (Cerrado) and to test the hypothesis that hydraulic lift by herbaceous plants contributes substantially to slowing the decline of water potential and water storage in the upper soil layers during the dry season. To this effect, field observations of soil water content and water potentials, an experimental manipulation, and model simulations, were used. Savannas of central Brazil exhibit consistent changes in tree density along shallow topographic gradients, from open savannas with relatively few trees in the lower portions of the topographic gradients to woodlands with a relatively high density of trees in the upper portions of the gradient. Herbaceous plant abundance follows the opposite trend. The diel recovery of soil water storage was higher in sites with more abundant herbaceous vegetation. Experimental removal of the above ground portion of herbaceous plants in a site with low tree density, during the dry season, substantially enhanced diel recovery of water potentials in the upper soil layers, consistent with the release of hydraulically lifted water from their shallow roots. In a site with high tree density, the release of hydraulically lifted water by woody plants contributed only 2% to the partial daily recovery of soil water storage, whereas the herbaceous layer contributed the remaining 98%. Non saturated water flow in the same savanna type contributed 8% to the partial daily recovery of soil water potential at the beginning of the dry season, decreasing to near 0% after 20 days of drought. During a 70-day rainless period the soil water potential dropped to -2.0 MPa near the soil surface. The simulation model predicted that without hydraulic lift, water potential in the upper soil layers in relatively dense savannas would have dropped to -3.8 MPa. The maximum contribution of hydraulic lift to the upper 100 cm of soil was 0.7 mm day-1 near the middle of the dry season. During the peak of the dry season, hydraulic lift can replace 23% of the ecosystem evapotranspiration in a site with high tree density and consequently greatly influences the water economy and other ecosystem processes in the Cerrado.

Keywords: Cerrado, leaf area index, non saturated flow, soil water model, soil water potential recovery

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

XML: View XML

Citation:


Scholz, Fabian G.; Bucci, Sandra J.; Hoffmann, William A.; Meinzer, Frederick C.; Goldstein, Guillermo. 2010. Hydraulic lift in a neotropical savanna: experimental manipulation and model simulations. Agricultural and Forest Meteorology. 150: 629-639.

 


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.