Tested with Viscous self-casting The Cube and Rescue Beam. They function normally on the ground (holding the self-cast key and pressing '2'), but when standing in this tree, it gives the error "Requires Target Hero". The spell can be self-cast if you double-jump out of the foliage of the tree. A single jump is not enough to restore self-targeting.
This behavior was replicated with Alternate Cast Button and with Double Tap Alternate Cast.
This behavior was replicated with Alternate Cast Button and with Double Tap Alternate Cast.