Software product line engineering is a development paradigm based on reuse. It builds a common platform from which a set of applications can be derived. Despite its advantage of enhancing time to market and costs, it presents some complications. Among them, the complexity of its evolution because all the components are shared between the derived products. For this reason, the change impact analysis and the evolution understanding in software product lines require greater focus than in single software. In this chapter, the authors present CASPL platform for co-evolution analysis in software product lines. The platform uses evolutionary trees that are mainly used in biology to analyze the co-evolution between applications. The major goal is to enhance the change understanding and to compare the history of changes in the applications of the family, at the aim of correcting divergences between them.