A five foot acer is worth far more than a fancy pot. Take a hammer to the pot and buy a new one.

I agree with Bulba and if you are potting into a larger pot then make sure it is wider at the top than bottom or the same width all the way up.

If you really don't want to damage either pot or tree, water the tree well, after about four hours run a long knife around the edge of the pot, turn the pot on it's side, position yourself underneath the tree, put one foot on each side of the pot, pull the trunk and you should be able to pull the tree from the pot. Plant the tree immediately into a larger pot or tub as Moongrower suggests.

Hmm, I'm not at all sure that'll work (Docbob's suggestion) but I guess its worth a try. It hasn't worked for me, speaking as someone who's been trying to get a 5 year old clematis out of a pot which has a rim inside, and I'm fast concluding I'll have to destroy the pot to get it out...

Don't worry Bamboo, it will work. I've seen it done and done it myself many times.

Good luck kgaul - me, I'd smash the pot!

Tried similar like your Clematis Bamboo - gave up after a couple of hours - the hammer came out!!

Its my belief that Acers shouldn't be grown in pots, after all they are trees. Couldn't you find a spot in the ground for it, you can keep it to the height you want it to be by
pruning it every year.

Chino if you have alkaline soil or a courtyard/patio garden growing in a container may be the only thing you can do... We have some small, weeping, Japanese acers that would be perfectly happy in large pots if necessary - thankfully we can grow ours in the ground.

I have a friend who has an acer that as been in a pot for 20yrs plus, and its beautiful