Mobile Ad Hoc Networks (MANETs) are widely used in emergency scenarios, disaster management, battlefield communication where no infrastructure is present. Innovating routing in MANET is crucial for unleashing the full potential of such networks. Due to lack of lightweight proactive routing scheme with strong routing capability, opportunistic data forwarding has not been widely used in MANET. We propose the new lightweight proactive routing based on concept of tree structure that will reduce communication overhead and provide nodes with more network structure information than distance vector (DV) based protocols [e.g. Destination Sequenced Distance Vector (DSDV)], Link State (LS) based protocols [e.g. Optimized Link State Routing (OLSR)] and reactive source routing [e.g. Dynamic Source Routing (DSR)]. The proposed technique provides every node with a Breadth First Spanning Tree (BFST) of the entire network rooted at itself. To reduce overhead, instead of broadcasting the entire network tree structure, it broadcast only the differential update message of the tree structure.