What kind of wood is it? Most definitely, it's very punky spalted stump wood.

Beyond that, it's very difficult to ID wood from a picture even when it is in pristine condition. When the wood is very punky and spalted it is practically impossible. If you want to make an educated guess about the species, if the wood came from somebody's yard that would be the easiest solution. Otherwise, the most common species in your area would be the most likely suspects and might be the best that you would be able to determine.
If you want to do some research, the best reference that I know of is, "
Identifying Wood" by R. Bruce Hoadley. He says that wood can be identified by closely examining the end grain growth rings and pores. A good magnifying glass, pocket microscope, or if you have a camera with a macro lens that would be very useful in helping you ID the species. If the wood is very rotten you might not be able to positively identify it, but you might be able to make an educated guess.
Before you do the finish turning, it would help immensely if the wood were fortified by soaking in thinned shellac or lacquer and then allowed to thoroughly dry. To minimize the chance of tear out I would recommend a very finely honed bowl gouge and take very light shear cuts (handle dropped very low (about 45°), bevel lightly gliding. If that doesn't work try shear scraping.