Influence of Fire on South Texas Chaparral Communities

Abstract

Experimental fall burning of South Texas chaparral communities significantly reduced canopy of all brush species in untreated areas and in areas previously treated by roller chopping, shredding, and scalping. There was a highly significant (P < .01) reduction in frequency of occurrence of lotebush (Condalia obtusifolia (Hook.) Weberb.), lycium (Lycium berlandieri Dunal.), and creeping mesquite (Prosopis reptans Benth. var. cinerascens (Gray) Burkart). Frequencies of occurrence of brasil (Condalia obovata Hook.) and Mexican persimmon (Diospyros texana Scheele) were significantly reduced (P < .05). There was no sgnificant difference in total amount of grass on burned and unburned areas 1 year following the fire. Filly panic (Panicum filipes Scribn.), buffalograss (Buchloe dactyloides (Nutt.) Engelm.), and meadow dropseed (Sporobolus asper var. hookeri (Trin.) Vasey) were more abundant on burned than on unburned areas. Plains bristlegrass (Setaria leucopila Scribn. and Merr.) was less abundant on burned areas than on unburned areas. Forb production was significantly (P <. 01) less on burned than on unburned areas, mostly because of reduction in western ragweed (Ambrosia psilostachya DC.) and Texas broomweed (Xanthocephlum texanum (DC.) Shinners). Fire could have been responsible for the creation of the brush mottes described by early explorers. The study substantiates the theory that fire suppressed brush on south Texas grasslands.