The scientists' findings reveal the impressive adaptive engineering of deep-rooted trees in adjusting the size and structure of their piping, or xylem, to maximize water uptake, maintain their integrity and avoid flow-blocking embolisms. In particular, the findings reveal how the deepest roots develop the largest conduits in order to draw deep water most efficiently.

The scientists' technique of studying tree roots in place offers a far more realistic look at how trees manage their water circulation than researchers have had before. The approach is like studying the plumbing of a house by carefully tracing its pipes, valves and faucets. In contrast, the usual approach -- drilling core samples and separating tree root samples for study -- is like taking a wrecking ball to the house and sifting through the debris to understand the plumbing system.

The researchers, led by biologist Robert Jackson, published their findings in the September 2004 issue of the journal "New Phytologist." Lead author on the paper was Andrew McElrone, formerly of Duke and now at St. Joseph's University in Philadelphia. Other co-authors on the paper were William Pockman of the University of New Mexico and Jordi Martnez Vilalta of the University of Edinburgh in the United Kingdom. Jackson is a professor of environmental sciences and biology in the Nicholas School of the Environment and Earth Sciences and a professor in the Department of Biology at Duke. The scientists' work was supported by the National Science Foundation, the Mellon Foundation and the U. S. Department of Agriculture.

In their study, the researchers took advantage of the fact that a well-mapped system of limestone caves runs beneath the Edwards Plateau in central Texas. Thrusting into t
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Contact: Dennis Meredith
dennis.meredith@duke.edu
919- 681-8054
Duke University
19-Aug-2004