Mesquite increased from approximately 18% to 40% in unburned controls over the experimental period, which contributed to lower fine fuel amounts. The rate at which mesquite canopy increased with time was principally governed by soil type. The rate of increase of mesquite after fire was the same as that of the untreated control treatments for each soil respectively. Following burn treatments in 1996, prickly pear cactus cover (Opuntia spp.) increased faster on the burned than the control areas but, following burn treatments in 1998 and 2000, cactus grew at the same rate as the unburned control. The amount of reduction of mesquite following each of the burn treatments differed. This was largely due to the amount of fine fuel available and the weather conditions when each burn was conducted.
After an effective prescribed fire the aerial cover of mesquite takes 6 to 7 years to return to pre-treatment levels. This is a critical value that determines treatment longevity and hence the frequency that the treatment needs to be applied. It is critical to calculating the long-term economic benefits of using prescribed fire as outlined in detail in the section on “Economics of reducing mesquite brush with herbicides and fire”.
Figure 3. Mesquite canopy cover changes over time in the no-burn control and in paddocks in the rotational-grazed treatments (4:1F and 8:1F pooled) burned in 1996, 1998 and 2000 on 3 soil types. Vertical lines with percentage values in the top panel represent the percent reduction in mesquite cover by fire in each of the fire years compared to the unburned control.
Publications
Teague, W. R., S. L. Dowhower, R. J. Ansley, W. E. Pinchak, and J. A. Waggoner. 2010. Prescribed Fire and Rotational Grazing in a Mesquite Savanna: I. Vegetation Responses. Rangeland Ecology and Management (In press)
Ansley R.J., W.E. Pinchak, W.R. Teague, B.A. Kramp and K. Barnett. 2010. Prescribed Fire and Rotational Grazing in a Mesquite Savanna: II. Mesquite Landscape Cover Responses. Rangeland Ecology and Management (In press)
Ansley, R. J., X. B. Wu, and B. A. Kramp. 2001. Observation: Long-term increases in mesquite canopy cover in a north Texas savanna. Journal of Range Management 54: 171-176.