Research shows trees are increasing spring flows
March 4, 2010

Recent research shows that large scale increases in spring flows are occurring as trees displace grasslands. In a report on physorg.com, Dr. Bradford Wilcox observes:

"...these landscapes are recovering, but they've also converted to woody plants," he (Wilcox) said. "We're also seeing large-scale increases in the amount of spring flows. This is opposite of what everybody is presuming - the trees are there and they are sucking up all of this water. The trees are actually allowing the water to infiltrate. There is a broad perception that the trees are making these natural springs disappear. This is definitely not the case."

He found that there is "more cedar than in the past". But in spite of cedar's proliferation, the report states that:

...contrary to widespread perceptions, springs in the Edwards Plateau, which provide much of the stream flows, have not been declining as a result of increased encroachment of woody plants. In fact, spring flows are twice as high as they were prior to 1950.

Wilcox is one of the preeminent scientists studying the relationship between trees and water availability and is a professor in the Department of Ecosystems Science and Management at Texas A&M University.

Scientists refute cedar "water hog" myth
August 13, 2008

New research by a Texas A&M scientist shows that Live oaks use more water than Ashe junipers and that juniper-forested sites use about the same amount of water as grasslands. Dr. Jim Heilman, Professor of Environmental Physics, believes that bulldozing the trees to save water is a case of "policy getting ahead of science".

In studies conducted at the Freeman Ranch near San Marcos, Heilman and his colleagues made measurements of 3 different landscapes: a grassland, a grassland with juniper and mesquite trees, and a dense forest of juniper and oak. He found that...

"juniper roots are actually shallower than oak roots, and the internal plumbing of juniper greatly restricts the amount of water that can be taken up".

In addition, Heilman noted that junipers sequester massive amounts of carbon.

"If we remove brush, we might have a marginal savings of water, but we're losing a heck of a lot of carbon", he said. "If we get into carbon trading markets, that carbon could be very valuable."

Programs to pay cattle ranchers for removing Ashe juniper have been popular because they were previously believed to increase water availability. These government subsidies enable ranchers to expand land available for grazing.

Dr. Heilman's findings were reported here by Blair Fannin of Texas AgriLife Extension Service.