Need to kill prickly ash and way to high stems count for basal application. Stem 1/4 to 1/2" dia every 18"= 1 million per acre. Going to buy new Birchmeier backpack sprayer after returning my Stihl last fall. Dealer could not keep it from leaking when full. Kicking around idea of also buying the gas powered fogger. Looks like could cover more ground but weight might wear me out faster. Have any of you ever used one for herbicide?