Posted: 28/09/2013 at 21:24
How old is the tree? There are 2 phases, juvenile and adult. Adult look symmetrical and umbrella like, juvenile (my fav) is less symmetrical like and shrub like.
You can prune Monkey Puzzle trees, you are advised not too (unless it is dying back and gone brown) as it affects the symmetry of the tree and it then looks lopsided. You can remove lower branches to make room (they will naturally fall off in time). Some people remove the growing points at the end of the branched to limit growth.
If you take the leader out to keep the tree small does work in keeping it smaller as long as it has not reached adult phase but even then I think it is only a matter of time that you think it looks odd and take it out anyway.