If you bore holes into the base of a tree near the flair of major roots at a time the carbohydrate stream is actively feeding the roots (sept. is good) a little Roundup poured into the holes will achieve the arborcide. What are you doing killing trees on public land? Have I just put a gun in the hands of an irresponsible adult?
[NAFEX] Roundup-discreet tree killer,
Alan Haigh, 07/07/2008