Here in PA we call it both ashleaf maple or boxelder, depends on what part of PA you come from. As Dr Bob pointed out, its acer negundo. It's a weed tree most places here in PA, invasive, and rarely strait. Grows mostly along streams and wet areas. My Dad's farm is full of it, every 4th tree. From a woodworking perspective, the wood is weak, splits and twists up when you try and dry it, but yes is very pretty with that reddish heart. That reddish middle varies though, and often does not get as pretty or as full as the pics you sent. Another thing, when you dry the wood and work it, that red stain fades in sunlight unless you treat the wood correctly. One mans trash is another mans treasure though, I have heard of woodworkers (mostly turners, bowls etc) in other parts of the country willing to pay big bucks for stuff with lots of red in the wood like your pics. Again, around here its just another junky soft maple, not even great firewood.