According to Maschler, Peleg and Shapley (1972) the bargaining set of a convex game coincides with its core and the kernel consists of the nucleolus only. In this paper we prove the same properties for [Gamma]-component additive games (= graph restricted games in the sense of Owen (1986)) if [Gamma] is a tree. Furthermore, we give a description of the nucleolus of this type of games which makes it easier accessible for computation.