Release of 7-year-old underplanted white pine using hexazinone applied with a spot gun

Abstract

Hexazinone, Velpar-L?, applied at rates of 1 .O, 1.5, and 1.75 ml per spot, controlled competing hardwoods around 7-year-old underplanted white pine. Growth response was more pronounced when hexazinone was applied to release individual pines than when the entire area was treated on a 6 by 6- foot grid. In most cases, hexazinone killed white oak, chestnut oak, American beech, sourwood, red maple, and black gum. Yellow-poplar, red oak, cucumbertree, black cherry, sugar maple, sweet birch, and sassafras showed variable sensitivity to hexazinone. Three years after treatment, resprouting of killed stems and white pine mortality remain low.