Published online by Cambridge University Press: 12 June 2017
Aerial herbicide treatments were made on a native stand of short-leaf pine (Pinus echinata Mill.) heavily infested with noncommercial oak (Quercus sp.), hickory (Carya sp.), and associated species in southeastern Oklahoma from 1957 through 1960. Two formulations of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) were applied in May and September at 1½ lb/A annually in one, two, and three applications with the later two made a year apart. The most diameter growth for all sizes of pine measured occurred following May treatments. Late May aerial applications also were made with 2-(2,4-dichlorophenoxy) propionic acid (dichloroprop) and 2-(2,4,5-trichlorophenoxy) propionic acid (silvex). Silvex reduced pine cone development, seed fill, and germination.
Native grass growth was increased twice following good weed tree control. However, where dense short-leaf pine seedlings developed, the native grasses were smothered and volume of herbage decreased.