Article
Interactions of pinyon and juniper trees tebuthiuron applications at 2 matched vaded sites in Utah
Journal of Range Management
(1993)
Abstract
Tebuthiuron{N-[5-(l,l-dimethylethyl)-1,3,4-thiPdiazol-2-yl~N, N’-dimethylurer} controls small trees in regrown pinyon-juniper woodland chainings. Precise applications by hand minimize cost and damage to forage plants. Little information exists on the applicability of local trials to varying Intermountain sites slated for reinvestment. We conducted 2 balanced factorial experiments at well-separated sites in the Great Basin and Colorado Plateau. Four rates (0.12,0.25,0.50, and 0.75 gm a.i. per 130 dmz crown volume) of tebuthiuron boluses were applied to tree stembase, mid-crown, or dripline placements. Four size classes (12~99,100-299,300-599, and 600-1099 dm3 crown volume) of Utah juniper [Jun$erus osteospermu (Torr.) Little] and single needle (Pinus monophylla Torr. and Frem.), and Rocky Mountain (P. edufis Engelm.) pinyon trees were treated in September 1985. Defoliation and mortality levels were estimated 24 and 36 months following treatments. Both sites received highly similar amounts of herbicide and cumulative precipitation. Analysis of variance showed that the presence and strength of main effects and first order interactions was largely site-specific. Pinyon was more susceptible than juniper at either site. Medium-sized and large saplings were apparently more readily defoliated than seedlings and small saplings. Dosage effects were generally nonlinear for both species. The highest, most rapid and most uniform defoliation and mortality of trees resulted from application of tebuthiuron at the stem bases. This placement option has strong operational advantages and minimizes damage to forage plants beneath trees.
Disciplines
Publication Date
1993
Citation Information
Neil E. West. "Interactions of pinyon and juniper trees tebuthiuron applications at 2 matched vaded sites in Utah" Journal of Range Management Vol. 46 (1993) p. 76 - 81 Available at: http://works.bepress.com/neil_west/147/