Potential detrimental effects of using glyphosate for hardwood seedling release

Abstract

Chemical release treatments are commonly used in regeneration efforts to establish new hardwood stands. These applications target the competing vegetation surrounding the desired seedlings. Research findings have suggested that release treatments improve seedling survival and growth during the initial years after disturbance or planting. Glyphosate is one herbicide that has been used by land managers to accomplish this objective. This study suggests that glyphosate may actually inhibit height growth of natural oak (Quercus spp.) and yellow-poplar (Liriodendron tulipifera) reproduction. Seedlings treated using glyphosate conducted as radial sprays, treating the immediate 5-foot radius around the crop trees, reduced height growth compared to control treatments. Natural reproduction was measured post spray in the fall of 2014 and two growing seasons later in January and February of 2017. This paper presents the reduced growth response through treatment comparisons of glyphosate with untreated control. Hypotheses are presented to potentially explain the causes of reduced seedling growth following radial release using glyphosate.

Parent Publication

• Proceedings of the 20th Biennial Southern Silvicultural Research Conference

Citation

Peairs, Stephen E.; Clatterbuck, Wayne K. 2020. Potential detrimental effects of using glyphosate for hardwood seedling release. In: Bragg, Don C.; Koerth, Nancy E.; Holley, A. Gordon, eds. 2020. Proceedings of the 20th biennial southern silvicultural research conference. e–Gen. Tech. Rep. SRS–253. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station: 302-306.