Was a big tree in a big forest, and was left alone while everything else was cut around it. The new full exposure to sun caused it to begin branching out all over. It was already a mature tree before this happened, and probably why it wasn't cut with everything else. The loggers knew it would have a lot of heartwood & very little white sap. Nothing wrong with the tree. It's just very old, past its prime, and now down. If I were to guess, i'd think you have a lot of trees under 12" diameter, a few big ones like that maple, and not a whole lot in between. That's just a guess, going on what I have seen in your pictures. Looks like the property was cut 10-20 yrs. ago.
edit: the last pic shows some sunburst rays. I can't tell if it's natural or if i'm seeing saw marks. If it's natural then you, sir, have a treasure on your hands. If those are rays & not saw marks, then you have a great big, mostly solid, very colorful birdseye maple log. Is there any possible way you could cut a 4-6" cookie from the butt or stump and break it in half, then show a close up picture of the grain?