Abstract: A recent study in wireless sensor networks (WSNs) has found that the link quality varies significantly with spatial and temporal factors and approximate 5\% to 15\% of all links are asymmetric links. The link quality services are used to measure and estimate the link quality between neighbors and provide the link layer relay mechanism to mitigate the effects of the unidirectional links. In order to provide the best reliable routing tree and reduce energy consumption, we developed a distributed algorithm to build the best reliable routing tree for every node using the link layer services. From statistic analysis and simulation using TOSSIM, we find that the algorithm can prevent from building a broken routing tree and build a more reliable routing tree. More than 17\% nodes have built more reliable routing tree and the percentage of the improved reliability is about 2\% to 51\%.