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The junipers that establish in overgrazed lands are young and vigorous, dense and multi-trunked, and shallow rooted.
This makes it difficult for remaining grasses to compete for water, especially if they are still being grazed and the soils are impoverished.
The presence of these dense, shallow-rooted shrubs also means less water reaches the soil, subsurface flows and deep drainage.
However, their dense canopies and thick litter do reduce overland flows compared to grazed grasses.
Old-growth Ashe junipers are different in that they have true trunks, use less water, are slow growing, less foliated and have very deep roots.
Wilcox ( Texas A & M University ) and Keith Owens ( Texas Ag.
researcher at Uvalde ) are currently studying how these deeper roots may facilitate the deep drainage of water down trunk stemflows.
Dr. Owens reports that for every one inch of rain, about 6 gallons of previously undocumented water is funneled down the trunks.

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