Basal Bark: Herbicidal Treatment

[@GrahamSEdwards]

How long is the dye on the basal bark visible? Is it just a matter of a couple weeks... or could it be visible for years?
Ideally, I'd like something that lasts a day or two... but, then disappears (so as not to be conspicuous).

[@steveh8724]

Thanks for this helpful guide to basal bark treatment methods and principles!