The Skills Tree offers a fast and easy way to incorporate a Skills Tree system in your project. Even though this is a C++ plugin you can leverage every one of its features in Blueprints. In case you’re a C++ programmer, the source code is fully documented so you can extend its functionality to match your needs (source code included in the UE4 marketplace product).
UE4 Marketplace link: //TODO
For the complete documentation check out my website: http://orfeasel.com/skills-tree-plugin-documentation/