Long-Term Effects of a 1969 Fire and Three 2,4,5-T Treatments on Prosopis glandulosa in Mitchell Co., Texas

Abstract

Response of 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) treated mesquite (Prosopis glandulosa var. glandulosa Torr.) to prescribed fire was described by Britton and Wright (1971). Average mortality was 12% 1 year following spring burning and 26% after 5 years on this upland site (Wright et al., 1976). Honey mesquite is rarely killed by fires on bottomland sites in the Rolling Plains or on the High Plains (Wright and Bailey, 1982). Prescribed burns often are used to reduce live canopy cover of standing mesquite, burn down standing dead mesquite stems, and consume mesquite debris following mechanical treatment. Long-term effects of mesquite-control practices on stand structure are lacking in the literature. Our objective was to document mortality, basal area, and number of stems of marked mesquite plants over a 21-year period during which several brush-control treatments were applied. Earlier studies (Britton, 1970; Britton and Wright, 1971; Wright et al., 1976) focused on effects of fire on stand structure; the current study reports continued monitoring of individual mesquite trees. The study site was described by Britton (1970) and Britton and Wright (1971). It was located in the Texas Rolling Plains 33 km south of Colorado City, Texas (110*50'W, 32005'N) on Dalby (fine, mixed, thermic Typic Torrert) and Stamford (fine, montmorillonitic, thermic Typic Chromustert) clays (clay flats range site). Average annual precipitation was 50.3 cm with most resulting from late spring and late summer convection storms. Vegetation overstory is dominated by honey mesquite, with nearly pure stands of tobosagrass (Hilaria mutica [Buckl.] Benth.) in the understory. Common broomweed (Xanthocephalum dracunculoides DC. Shinners.) was common