Redberry Juniper Response to Picloram and Top Removal in the Texas Rolling Plains

Abstract

Redberry juniper (Juniperus pinchotii Sudw.) mortality was evaluated following top removal, picloram application (1, 10, 20%, and 4 cc/3 ft of plant height), and cut-stump treatment with picloram (1, 10, 20%) on clay flat and shallow redland range sites in the Texas Rolling Plains. The objectives were to determine mortality of redberry juniper following different treatment regimes, and develop sound recommendations for redberry juniper management. Fifty trees were reandomly assigned to each treatment. Trees mechanically treated were cut to approximately a 4-inch stump height with a chain saw. Chemically treated trees were sprayed with a basal application of picloram. Trees that received a mechanical and chemical treatment were cut to a stump height of 4 inches and immediately treated with picloram. On the clay flat site, treatments of cut and spray 10 and 20% resulted in 100% mortality, whereas the cut only treatment had the lowest mortality at 7%. Trees in the cut only treatment had the highest number of resprouts, and the cut and spray 1% treatment was the only mechancial and chemical treatment combination that resprouted. The shallow redland site had similar results, with the cut and spray treatments having the highest mortality. Since labor is a major expense in individual plant treatments, spray only treatments are the least expensive treatments when evaluating cost per killed tree. Our results indicate that on both sites, the spray only 10% treatment optimized redberry juniper mortality while minimizing treatment cost. Based on these results, we recommend a basal application of a 10% picloram solution for managing redberry juniper in the Texas Rolling Plains. However, if the management objectives include removing the trees, then we recommend cutting the trees and immediately treating the stumps with a 10% picloram solution.