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Abstract
Intermingled pines and mountain whitethorn were treated with foliar sprays of 2,4-D and 2,4,5-T to test their effects according to (1) season of year, (2) concentration of spray on individual tree-brush clumps, and (3) spray dosage applied on an area basis. Spraying with 2,4,5-T in September resulted in the best tree growth and most brush kill; 2,4-D caused the most tree damage and was less effective as a brush killer. The best brush kill resulted from application rates of 400 to 600 ppm of 2,4,5-T, but these concentrations reduced tree growth. After two full growing seasons, average height growth of the pines was greater on plots receiving from ¼ to 1 pound of 2,4,5-T per acre than on the control plots. Application rates of 2 and 4 pounds per acre (ppa) gave best brush kill but caused severe damage to the pines.
Citation
Baron, F.J.; Stark, N.; Schubert, G.H. 1964. Effects of season and rate of application of 2, 4-D and 2, 4, 5-T on pine seedlings and mountain whitethorn in California. Journal of Forestry. 62(7): 472-474.
