Suppression of resprouting in pruned mesquite ( Prosopis glandulosa var glandulosa) saplings with chemical or physical barrier treatments

Chemical and light barrier methods were evaluated over a 2 year period as to their effects on suppression of resprouting in pruned mesquite saplings. Trees were thinned and pruned leaving one clear stem. A randomized complete block design with five blocks was used in both 1995 and 1996. From the 19 treatments examined in 1995, 10 treatments were selected for further study in 1996. The chemical treatments were applied to the pruned site with a paint brush in 1995 and a spray bottle in 1996. After each growing season the resprouts were harvested and weighed. The greatest mean reduction in resprouts was obtained with the 20% triclopyr concentration in diesel fuel in 1995 and 20% triclopyr in vegetable oil in 1996. When averaged over both years, the non-chemical, light-barrier, tree-wrap, had the lowest resprout along the main stem. However, this treatment did not control the profuse sprouting from stumps from multiple ground level stems of the same tree. The highest concentrations of triclopyr had the lowest tree growth rates. Additional long term experiments are needed, particularly with triclopyr, to find the techniques for resprout reduction that will not reduce tree growth rates.