Not sure from those photos, Tom. If you have some silver maple or tulip poplar handy, compare the weight of those to your wood in the photo. If it's quite a bit heavier, you have some kind of hardwood. All hardwood is good wood.
Things like silver maple and tulip tree can be good too, but the question is putting the labor into cutting, hauling, splitting, etc.
Try to get oak, maple (sugar or red), hickory, locust, ash, elm, or beech first. They're all good. Oak, hickory, and beech are my personal favorites. Of the lighter-weight woods, native black cherry is best, in my book.
Elm is not easy stuff to work with, in my opinion. But if you have it in volume, it gives plenty of heat.