Early Spring Broadleaved Weed Control during Seedling Dormancy in Regenerated Pedunculate Oak Forests

Abstract

In regenerated oak forests, weeds are present throughout the year, with the ones appearing in early spring representing a major problem. Hence, the aim of this study was to examine herbicides for early spring broadleaved weed control in regenerated oak forests while the seedlings are in a dormant stage. During 2019 and 2020, two experiments were set up in regenerated pedunculate oak forests with 2- and 3-year-old seedlings, and two herbicides were applied in two doses: fluroxypyr at doses of 360 g a.i. ha−1 and 540 g a.i. ha−1 and clopyralid at doses of 100 g a.i. ha−1 and 120 g a.i. ha−1. Fluroxypyr and clopyralid significantly reduced early spring broadleaved weeds in the regenerated pedunculate oak forests, but both doses of fluroxypyr provided greater control of the presented weeds than the applied doses of clopyralid. Manual weeding reduced broadleaved weeds in the experiments, but that method did not have a long-term effect on the reduction in weeds. The applied doses of the herbicides fluroxypyr and clopyralid did not cause phytotoxicity symptoms in the dormant oak seedlings. All investigated treatments significantly reduced fresh broadleaved weed biomass compared to the control. Fluroxypyr and clopyralid can be successfully used for the control of many early spring broadleaved weeds in regenerated pedunculate oak forests, but 2- and 3-year-old oak seedlings must be in the dormant stage.