To my knowlede, it's currently not possible to transfer ownership of a tree to another person and i think this needs to be remedied.
It's in the nature of things that it will span over generations and somehow someone else needs to take over. The GedCom way wont work, too much is lost.
I'd like to see another set of roles, perhaps adding an Admin role to the tree where you can have more than one Admin with Owners permissions.
/// Martin ///