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Publication Information

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Title: An Old-Growth Definition for Southwestern Subtropical Upland Forests

Author: Diamond, David D.;

Date: 1998

Source: Gen. Tech. Rep. SRS-21. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 12 p.

Publication Series: General Technical Report (GTR)

Description: Mainly evergreen, broad-leaved forests in the Southwestern United States are restricted to the Lower Rio Grande Valley of Texas. The soils and long growing season make this region valuable cropland, and, thus, almost all of the area once occupied by this forest type has been converted to row crops. Remaining old-growth forests are usually dominated by some combination of the broad-leaved evergreen Texas ebony and a host of other species. Few quantitative studies have described the composition of this forest type, and, likewise, little is known of the dynamics. Droughts, flooding regime, and fire were large-scale disturbance factors. Now, the Rio Grande is used extensively for irrigation, and flooding is controlled. Therefore, the presettlement water regime has been greatly altered, and vegetation of the remaining forest fragments is also adjusting to the new moisture regime. Some areas are wetter and some drier than in historical times. Many of the fragments that remain have already been incorporated into public ownership by the U.S. Fish and Wildlife Service or the Texas Parks and Wildlife Department.

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Diamond, David D. 1998. An Old-Growth Definition for Southwestern Subtropical Upland Forests. Gen. Tech. Rep. SRS-21. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 12 p.


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