Vegetation Cover Response and Second-Year Loblolly and Slash Pine Response Following Bedding and Pre- and Post-Plant Herbicide Applications in Florida

Site preparation treatments of early single bed (EB), late single bed (LB), double bed (DB), EB + banded pre-plant herbicide (PP), and EB + broadcast pre-plant herbicide (BPP) were applied to four locations in Florida. Three of the four locations included these treatments crossed with a first-year post-plant herbicide application to control herbaceous vegetation(HC). Second-year pine heights evaluated at two slash pine (P. elliottii Engelm.) locations and one loblolly pine (P. taeda L.) location averaged taller (4.6 vs. 3.5 ft) following double-pass (DB, PP, BPP) than single-pass (EB, LB) treatments, taller (4.9 vs. 4.0 ft) for pre-plant herbicide (PP, BPP) than DB, but did not differ between PP and BPP. There were no significant interactions between site preparation and HC with HC, increasing second-year pine height by 0.5 ft. Pine height was greater for pre-plant herbicide treatments than for DB treatments because pre-plant herbicide treatments provided better control of competing vegetation. Vegetation control differed among treatments. DB improved control of woody shrubs over single bedding alone, but increased herbaceous cover in the first growing season. The increase in herbaceous cover following DB accounts for the relatively small gain in second-year pine height (0.2 ft) for DB compared to LB. Pre-plant herbicide treatments following early bedding improved control of both woody shrubs and first-year herbaceous vegetation. Pre-plant herbicide treatments also shifted the composition of herbaceous vegetation towards less competitive species. HC improved control of herbaceous plants, and lowest first-year herbaceous cover was achieved with the combination of HC with pre-plant herbicide treatments. South. J. Appl. For. 25(2):75–83.