1. A method for configuring a channel node tree in an Orthogonal Frequency Division Multiple Access (OFDMA) wireless communication system, comprising: configuring as many Distributed Resource CHannel (DRCH) nodes as the number of DRCHs used for a frame at base nodes, selecting as many Blocked Resource CHannels (BRCHs) as the number of DRCHs from among BRCHs used for the frame, and configuring BRCH nodes at base nodes by mapping the BRCHs used for the frame to unselected BRCHs; and configuring upper nodes using the base nodes corresponding to the DRCH nodes and the BRCH nodes.