Herbicide effectiveness for Redcedar control in Oklahoma and Missouri

TitleHerbicide effectiveness for Redcedar control in Oklahoma and Missouri
Publication TypeJournal Article
Year of Publication2018
AuthorsLourencon, RV, Hart, SP, Gipson, TA
JournalJournal of Animal Science
AbstractIn a research study using goats to control redcedar (Juniperus virgiana), herbicide was used as a treatment. The objective of the study was to measure the degree of control of redcedar provided by herbicide in the South-Central U.S. There were three research plots in Oklahoma: Langston, Oklahoma City and Mannford, and one in Neosho, Missouri, all 0.81 hectares. The redcedar population was inventoried, quantified as to height, width and GPS coordinates. Trees over 0.61m in height were individually treated in November 2016 with Velpar® herbicide, in accordance with recommendations of the manufacturer, a syringe was used to administer (3 mL per 0.91m of basal diameter) to the base of the tree. Percentage green cover of the cedars was measured 8 months after application. The percentage of dead (0% green) or live trees according to size (short; ≤ 1.83m or tall; > 1.83m) were analyzed using Chi-Square statistics. A subsequent multiple regression analysis was conducted for tree height, tree width, and herbicide dose against the percentage of green canopy cover. Trees in Mannford and Oklahoma City had the least percentage green (4 and 8%, respectively, P = 0.1386), followed by Langston (14%, P < 0.05) and then Neosho (31%, P < 0.001). In all locations, the herbicide was more effective with shorter than taller trees (P < 0.001). Herbicide killed 68% of trees shorter than 1.83m, as compared with 31% the trees taller than 1.83m. Shorter trees averaged 10% of green canopy, while the taller trees averaged 18%. For each 0.366m of increase in tree height, there was 2% increase in green canopy cover. This may indicate that tall trees need a higher dose of herbicide than used in this study.