• Controlling Individual Junipers and Oaks with Pelleted Picloram

      Johnsen, T. N.; Dalen, R. S. (Society for Range Management, 1984-07-01)
      Applications of pelleted picloram to individual plants of alligator juniper, one-seed juniper, Utah juniper, gambel oak, and shrub live oak in north central Arizona showed that a high rate application, 3.6 g acid equivalent (a.e.) picloram (4-amino-3,5,6-trichloropicolinic acid) per meter of juniper height or meter2 of oak clump crown cover, controlled each of the species. However, only Utah and alligator junipers were consistently controlled by lower rates, 1.8 g a.e. or less per unit of plant height. Regression formulas were developed to determine estimates of the amount of herbicide needed for effective control. Large scale pilot trials were done to expand application of results.
    • Managing individual juniper and pinyon infestations with pelleted tebuthiuron or picloram

      Johnsen, T. N.; Dalen, R. S. (Society for Range Management, 1990-05-01)
      Junipers (Juniperus spp.) and pinyons (pinus edulis Engelm.) are reinfesting areas from which they have been removed and are encroaching into other areas. Controlling these trees while they are small would help maintain forage production and protect the soils. Individual trees can be controlled by applications of pelleted picloram (4amino-3,5,6-trichloro-2-pyridinecarboxylic acid) and tebuthiuron [N-[5-(1,l-dimethylethyl)-l,3,4thiadiazol-2-yl]N-N-dimethylurea), but little is known of the comparative effectiveness of these herbicides on junipers and pinyon. We compared pelleted picioram and tebuthiuron on individuai alligator juniper (J. deppeana Steud.), one-seed juniper [J. monosperma (Engelm.) Sarg.], Utah juniper [J. osteosperma (Torr.) Little], and pinyon. Pellets were applied at 0.7 and 1.4 g picloram acid equivalent (a.e.) or tehuthiuron active ingredient (a.i.)/m of tree height at 3 Arizona and 3 New Mexico locations. Utah juniper and pinyon trees up to 2 m tall were killed with 0.7 g picloram a.e. or tebuthiuron a.i./m of height. One-seed junipers up to 2-m tall were killed by 0.7 g tebuthiuron a.i./m of height, but were not by picloram. Neither herbicide killed alligator juniper consistently. Some understory grasses were damaged more by tebuthiuron than by picloram.