Had 2 species of walnut I took down at a house last year. Both are different species and very different bark on them. This one has barn like a traditional walnut tree, the other was grey and smooth. This was just a branch, I’ll open up the main trunks in a few weeks and see how they compare and if we can ID them. The heartwood in both isn’t very large like usual black walnut I see. It seems to be a pretty even 50/50 in the main trunk.