Efficient geocast routing schemes are needed to transmit messages to mobile networked devices in geographically scoped areas. To design an efficient geocast routing algorithm a comprehensive evaluation of different routing tree approaches is needed. In this paper, we present an analytical study addressing the efficiency of possible routing trees for geocast packets. We evaluate the Shortest Path Tree, Minimum Spanning Tree and a Steiner Heuristic based routing tree for geocast packet distribution on real world networks and random graphs. We compare the results to those for multicast routing for which such evaluations have been performed in the past. Our results show that due to the correlation of geographic distance and network distance in most wired networks, Shortest Path forwarding efficiency can come close to an ideal Steiner Tree. We also identify a correlation between the forwarding efficiency and network characteristics such as the node degree and betweenness. This information could be useful in deciding on a choice of routing method or even help with network design.