Hi Jim you can transplant maple however I suspect that most of yours has originated from stump sprouts. This means that your young looking sapling may actually have a very old and large root system. When the trees were originally harvested to establish the tree plantations the red maple would have established new growth from the stumps. This new growth would have used the original trees root system and over time the christmas tree grower probably cut and sprayed these and the process repeated itself. I live in western N.B. and just cleaned a wild christmas tree plantation with a thinning saw, it was full of Red maple that had grown from stump sprouts. These have been cut or sprayed for over 30 years now, and every 2 years they need to be cut again. The area I live in has a very large amount of Ironwood (ostrya virginiana), probably the largest amount that you will find any where in the maritimes. Even here this tree normally grows in the understory and doesnt tend to pop up everywhere. Could these trees possibly be Birch? They tend to grow in the open, Grey birch, white birch and even yellow can look somewhat like ironwood when young. If you had some pictures of the leaves and bark someone here could help with I.D.
If your trees have originated from seed you may try root pruning them in the fall and transplanting them in the spring. Smaller always transplant better. I did have a good article on root pruning however I can't find it right now. Try google and you may even find some images.
Regards
