I've got a fence line that I share with a neighbor. Never had any issues with trees, but I have noticed he trims the branches of mine that lean over into his (treeless) property. No big deal. Today I was walking the fence line and noticed a bottle placed in between one of the branches of a tree on my side. It was upside down, cap on, with some plastic wrapped around it. Seemed like it was set up for a slow drain into the tree. I removed the bottle, unscrewed the lid to see what it smelled like and it's some thick oily glue type stuff. I looked for cuts on the tree but couldn't really tell if there were any or not. The leaves are already brown and it appears to be dead already. Honestly, I may have considered taking the tree down if he had just talked to me about it, but now things are all ***ky and I've obviously got a crappy/sneaky neighbor. What should I do? I don't particularly like the idea of this jerk putting unknown chemicals in my yard close to where my kid plays.