Amenable actions of nonamenable groups

We give two ways of constructing amenable (in the sense of Greenleaf) actions of nonamenable groups. In the first part of the paper we construct a class of faithful transitive amenable actions of the free group using Schreier graphs. In the second part we show that every finitely generated residually finite group can be embedded into a bigger residually finite group, which acts level-transitively on a locally finite rooted tree, so that the induced action on the boundary of the tree is amenable on every orbit.