Trees are very often used to structure data. For instance, file systems are structured into trees and XML documents can be represented by trees. There are literally as many access control schemes as there are tree data structures. Consequently, an access control model which has been defined for a particular kind of tree cannot be easily adapted to another kind of tree. In this paper, we propose an access control model for generic tree data structures. This model can then be applied to any specific typed tree data structure.