In ad hoc wireless networks, nodes are typically powered by batteries. Therefore saving energy has become a very important objective, and different algorithms were proposed to achieve power efficiency during the routing process. Directional antenna was suggested to further decrease transmission energy as well as to reduce interference. We discuss three algorithms for routing tree construction that take advantage of directional antenna, i.e, Simple-Linear (SL), Linear-Insertion (LI), and Reverse-Cone-Pairwise (RCP). Their performances are compared through a simulation study.