Hi, ERC is a juniper and as far as I know all juniper's can be treated as a 'White Wood'. No ring chasing necessary, the sap wood is just as strong as the heart. Of course the wood is weak in tension , but works great with a light backing. I've made a couple of juniper bows that I decrowned and backed just so I would get more heart wood in the bow. They didn't shoot better, but they sure looked nice. If you're decrowning before backing, I think its safe to violate some rings, as the backing is going to be doing the tension part.
Ron