Cotoneaster? It would help to see the tree or shrub shape, the leaf arrangement (simple or compound, opposite or alternate), and a clearer view of the underside of the leaves. Mountain ash would have compound leaves.
Thanks a lot. I think you are right. Definitely not compound leaf. Will shoot the leaf arrangement next time I go to QEP.
Ditto to a Cotoneaster, probably Cotoneaster × watereri, a large shrub very popular in institutional / commercial planting schemes.