Depends on the tree, depends on its stage of development (should be closer to 'finished' than anything), and depends on when... you can defoliate a mature maple in late June and it'll have time to grow new smaller leaves before the end of summer, but not all trees react so well, some only can take partial defoliation, and some react badly, so you have to learn more about each one.

Various factors lead to leaf size reduction as I understand it.

Leaf cutting on certain species is certainly one technique to get a rapid reduction in leaf size. This is usually done in early summer by cutting the leaf off at the top of the leaf stalk, leaving the stalk intact. New smaller leaves grow at the bases of the old leaf stalks which then drop off.

I've always viewed this as a short term measure to, for instance, get a tree ready and looking better for a show a few weeks later.

Lucy is quite correct to identify this as a technique used on trees in their final stages of development and it's not the thing to try willy nilly on potensai or trees in early development as its more likely to knock the tree back a few months than promote a long term tendency toward smaller leaves.

Other elements of the story are more long term.

Regular root pruning to build up a mass of fine fibrous roots and restriction of these healthy roots in a small pot seems to be one factor.

Increasing the ramification or twiggyness of the tree is another major factor.

Regular pruning of shoots stimulates more buds further back on branches in many cases.

If you think about it - lots and lots of fine feeder roots pushing to grow lots and lots of leaves at lots and lots of potential budding points on lots and lots of small twigs = lots of small leaves.

The physiology? of the tree means that is tries to produce a leaf at each potential budding point but it only has a finite amount of reserves to produce them. Accordingly the result is smaller leaves and more of them.

The alternative would be for the tree to product one big leaf but they don't respond that way.

Probably grossly oversimplified but hopefully not wildly inaccurate.

Just an aside.

Seems to be a few "Bluenosers" about on the forums Lucy - you should all form a club.

Not much else to do out east I guess.

LOL
:-)
:-)

Only joking

Tim (former Ontarian)

Leaf pruning is not a short cut to smaller leaves. It CAN be, but the primary function of removing leaves is to increase ramification (twigginess) of branches. Smaller leaves are USUALLY a side product of this. Leaves, depending upon species and sun exposure, can actually produce large leaves after this procedure is done.

Yes, you can severely weaken or even kill your tree with this procedure, especially if the plant is weak when you do it. It is a technique done on already develeoped bonsai and isn't recommended for trees undergoing other more basic techniques like growing out trunks, or creating branch structure.

Some trees, like some species of beech (American Beech) and hornbeam (Korean Hornbeam in particular) don't respond well, or as readily to this technique as more vigorous species like trident maple. Some japanese maple species, especially the cut leaf and thread leafed cultivars, will suffer greatly, if they have their leaves pruned.

You should never leaf prune the same year you repot and root prune a tree.

Can this be done on 1/2 the leaves or a few at a time on a Trident Maple with significant results?

For example, prune back to two leaves where there are too big of leaves on a branch.

On maples, it can be done with just about all leaves at the same time, but when you say 'prune back to two leaves', be careful what you mean, because if you just cut a branch down to those 2 leaves, you may end up encouraging more ramification (twiggy new growth with more leaves) and while the leaves may be smaller (or not) you will have more bushiness. If you're removing leaves to shrink them, you cut halfway through their stems where they attach to the branch, but you don't cut the branch itself unless you want more branches.

Thanks Lucy, I was talking about two different things.

On the defoiliation, you actually cut half way down the stem instead of cutting the leaf right where it is attached to the stem (leaving the entire stem intact)?

As long as you're aware you're replying to an 8 yr old thread...

Google brought me here. The timeline of the posts have no affect on the accuracy of information.

Thank you Umair for your constructive contribution.