While taking the CGMA course Organic World Building in UE4 by Anthony Vaccaro, I created a bark texture that turned out to be quite simple and effective. I hope I will have time to make a short tutorial to share with other students how it was done, but for now, I am posting an image showing a break down.

A high resolution version that can be zoomed in to read the node titles is available for free at https://artstn.co/m/oPjB.

The graph it quite straightforward and should be easy to understand. The main thing to pay attention to is that the warp nodes for the base color are mirroring the warping of the height map, to make sure that the two are kept in sync.