I know where there are some very nice trees that if you don't mind digging them up. Your welcome to them. I would say they have been in the ground for maybe a few years maybe 12' to 15' tall and very healthy. Light rail is going through the property and the building is already gone. I can take some pictures if you like. If no one takes them they are going to just rip them up. I think they a birch but not for sure. Right by 48th and Fox in Denver. There is around seven or so of them.
Jerry