Red-cockaded woodpecker (Picoides borealis) colonies on the Angelina National Forest were monitored from 1984-1986,after hardwoods on the site had been injected with the herbicide 2, 4-D. The herbicide effectively reduced the hardwood midstory; however, possible toxicity to woodpeckers and cavity tree mortality are problems associated with the use of 2,4-D. Because of its lower toxicity to pines, the herbicide hexazinone is suggested as an alternative to 2,4-D. Use of any herbicide is suggested only as a one-time application to eliminate large hardwoods so that prescribed fire can later be used to control hardwoods in woodpecker colonies.
Conner, Richard N., "Injection of 2, 4-D to Remove Hardwood Midstory Within Red-Cockaded Woodpecker Colony Areas" (1989). Faculty Publications. 425.