it's a black oak... or what i believe to be a black oak, something it the red oak family at least i suppose, with the large 5 point leaves, the rough bark goes a long ways up, but isn't yellow inside it. i've had two large limbs break off, and they have black veins/hollow areas going through them. i took another one like it down last year when i noticed it seemed to be falling apart as well, and the black ran up the trunk a good ways, and into some of the limbs. also, contrary to common knowledge, the one from last year was as fun to split as a sweet gum. both of them about 2 feet in diameter, and 60-70 feet tall, but with only a 20-30 foot spread... but maybe that's due to both being at the edge of a densely wooded area. does this sound like some kind of disease? if so, would it spread to others? thanks.