Over the last century, Wireless Sensor Network (WSN) has given major advances in several distinguishable fields. In addition, it has also evolved many features such as high device heterogeneity, high scale and supporting multiple applications. In WSN, Key management is employed (involves) as a significant component of network security, especially in multi-cast based applications and services. Group key management has a vital role in multi-cast secure communication with huge number of group members. Group key must always be updated dynamically to all groups in the network and keys to be redistributed currently to active members only. Consequently, a secret key called session key for a group of members is stored in key trees that are shared efficiently between them, in order to achieve secure group communication. The key trees are used to encrypt with other keys and data are transmitted to ensure security. Logical key hierarchy (LKH) is a hierarchical structure of multiple keys to provide a scalable and secrecy for group communication. This research work proposes a new hierarchical group key management (HGKM) using multiple logical key trees for dynamic groups in order to enhance the Quality of Service of the network. Among the multiple logical trees, primary tree can be selected by tree selection algorithm. In WSN, there are high numbers of members joining or leaving the group at any time, resulting with rekeying process becoming too large. This leads to degraded efficiency of tree-based key management system. Further, communication overhead of rekeying process can be mitigated by one-way key derivation method which integrates with multiple logical key trees. In this method, tree server does not need to be encrypted. Rather, it involves in sending a new key to members who are capable of derive their own keys in same way the server does. This results with a need for less number of encrypted keys for each rekeying process within the group tree. The fixed interval time is called batch time, which is applied in each rekeying process after nodes join or leave the group. The proposed approach can improve the bandwidth utilization effectively. The proposed HGKM method is implemented in Network Simulator (NS-2) environment and obtained results are compared with existing two methods such as LKH and multiple logical tree key management (MLT-KM). QOS of proposed approach is evaluated in terms of Bandwidth Efficiency.