This is a strange thing that I've noticed. In researching about this type of spruce, I found a website that said, "All Adirondack Spruce is red spruce. Not all red spruce is Adirondack." But I'm not sure about this notation. Adirondack Spruce is commonly used as a name but it's more a location of quite a bit of red spruce from that area. And according to Wikipedia, "This species (Picea rubens) is also known as yellow spruce, West Virginia spruce, eastern spruce, and he-balsam." So I think in guitar building they're one and the same, but for documentation purposes it's more clear to call it red spruce and leave the location alone. So basically, what he ^^^ said.