I have a barrel diagonally next to a tree in a Steve's Carts tree farm, and when the tree grows, the leaves delete the Pneumatic Tube that goes into the top of the barrel. This doesn't happen when I grow a tree normally. So beware: trees grown by Steve's Carts may destroy your stuff. Or... maybe it's the Deployer that's deploying Bonemeal doing it? I can't make one do that in a test world though.