A smart adaptive antenna has multiple Degrees of Freedom (DOFs), which can be used for intended communications and interference suppression. In this paper, we study routing and scheduling in wireless backhaul networks with smart antennas. In a wireless backhaul network, a spanning tree rooted at the gateway node is usually constructed for routing. We formally define the Interference aware Tree Construction Problem (ITCP) which offers full consideration for interference impact and DOF availability, and present an algorithm to optimally solve it in polynomial time. As for scheduling, we first present a polynomial-time, optimal algorithm for a special case in which the number of DOFs in each node is large enough to suppress all potential secondary interference. An effective heuristic algorithm is then presented for the scheduling problem in the general case. Extensive simulation results have been presented to justify the efficiency of the proposed algorithms.