This is just sad.
Just playing the environmental scientist devil's advocate.... but depending on the amount of herbicide he dropped (has that been said yet?), and the depth to the most shallow groundwater table, the contamination could still be an issue. A "dig and haul" (what they're doing now) is going to be the best bet for immediate results. I'm not an arborist, but I feel like there is something out there that when applied can counter the effects?
In interesting FYI related news, I sample hybrid poplar trees once a year (about 2,000 trees) that were planted over an extremely concentrated TCE plume. The trees are actually remediating the chemical on their own.
