Rainbowgardener, thanks for posting that link. I was able to pretty definitely ID a maple sapling as Red Maple and a desired species. I was afraid that it may be Norway Maple, or possibly Silver Maple. I guess it stays.

I also have several other volunteers that I'm going to add to my line-up for possible bonsai subject.
Devin Heinle, good luck with yours. So far, my very untechnical method for intentionally growing tree seeds from local trees has been to sow them in a well-draining potting mix (I mix my own out of garden top soil, compost, some decayed tree stump chips, and sand) in 6"~8" pot, and leave them outside directly on the ground in a sheltered area under a tree (buried in a leaf pile) where it will get rained on but won't be sitting in any puddles. It's a bit of a hit-or-miss, but unless the squirrels or chipmunks dig up the seed (Sometimes they just dig up the soil to plant their OWN stash, and something completely different end up growing in the pot. Presumably, my own seed has been flung away or EATEN.

) most of them sprout in the spring.