The Wireless Sensor Network (WSN) applications are today not only limited to the research stage rather it has been adopted practically in many defense as well as general civilians applications. It has been witness that extensive research have been conducted towards energy efficient routing and communication protocols and it has been reached to an acceptable stages, but without having a secure communications wide acceptance of the application is not likely. Due to unique characteristics of WSN, the security schemes suggested for other wireless networks are not applicable to WSN. This paper introduces an novel tree based technique called as Secure Tree based Routing with Energy Efficiency or STREE using clustering approximation along with lightweight key broadcasting mechanism in hierarchical routing protocol. The outcome of the study was compared with standard SecLEACH to find that proposed system ensure better energy efficiency and security.