The weary traveling adventurers were passing through the forest when suddenly they heard voices softly conversing about how the isolated forest was not so isolated any more. They stopped to listen and see who was having the conversation. It appeared to be on the other side of the tree, but after going about the circumference they found no one. Suddenly the words stopped and still no one to be found. They hadn't thought that the tree might be hollow.
This is a modification of the tree fort as requested. It has a top that is leaved branches that can be placed over the hollowed out tree trunk home. There is also a door to hide the opening. The top branches can be removed to see into the tree home. Glue the lower lid to the upper part of the tree to have a tighter fit that won't separate when bumped.