Hyperfinite equivalence relations are treeable. For the case of uncountable relations, I was wondering if there is a reference to (or simple proof of) the following statement: Let $E$ be a (possibly uncountable) amenable equivalence relation on a standard probability space $(X,\mu)$. IfThen $E$ is not treeable then it is equal (mod $\mu$) to $X \times X$. Or perhaps is this statement incorrect?