I have a bunch of random trees growing from seed. Mainly maple and locust from seeds falling all over and germinating on their own but some semi-tropical fruit I have started in pots.

As some of the stems are vrey close together would it be possible to graft the two trees together vertically. I have seen various ficus sold as novilties where branches were trained and grafted between trunks much like a ladder.

What would happen if I were to remove the bark and expose the cambium in each tree, say, 4 inches above the soil line then pull the two trees contacting the cambiums and tape accordingly. Might this create an X shaped tree or even a single trunked tree having two legs into the soil? Or would one just choke out the other?