Yeah as darthviper said that’s SpeedTree Cinema, mainly for pre-rendered stuff. You can technically import the models in UE4 as fbx or obj file but I wouldn’t expect a flawless workflow based on that.
If you want to have a better idea about what ST8 for UE4 is going to be I think you should take a look at UE4 for Lumberyard: https://store.speedtree.com/speedtree-8-for-amazon-lumberyard/