The crux of large scale Application Layer Multicast or Peer-to-Peer streaming systems is how to cope with the inherent dynamics, the reason is that the participating users may join and leave at will. It is even worse for single-tree-based multicast systems, which are preferred due to their efficiency. In these single multicast tree based schemes, userpsilas departure may cause serious service disruption for all the downstream users. The solution stems from the characteristics of the problem itself, and it exploits the property that the participating userspsila lifetime follow a Pareto distribution, which has the used better than new (UBTN) feature. The participating nodes are dynamically organized into a hierarchy in such a way that it reflects the relative stabilities among the nodes. The proposed algorithm is distributed in the sense that no a prior knowledge about userspsila lifetime is needed. A maximum of 50% improvement can be achieved in terms of peerspsila perceived QoS. Detailed mathematical analysis and simulation results are presented to validate the proposed algorithm. Simulation results show that the algorithm is valid for other lifetime distributions as well.