Sometimes you get what I call a bad day at the office, you have found a great looking branch fork and the end grain looks different to what you have seen before.
You can only tell what the inside will look like by sectioning and this is usually done with a hand saw. By the time you get this far you have made quite an investment that you need to let go of and move on.
My preferred saw is a 14" Bahco saw with fine teeth. It does mean a longer time to cut but provides a result that let you see the "Y" wood grain with only minimal sanding.