I have a number of apple, pear, cherry and peach trees in my garden. To prevent girdling by rabbits during the winter, I have always wrapped the trunks with some form of tree wrap. The trees are now 5 or 6 years old and the bark on the trunks is more mature and rough, not smooth and "tender" like it was when the trees were very small.

Here are my questions: Is it necessary to continue to wrap the trunks? Is that something I should do as a matter of course indefinitely? Or is there a point when the rabbits will leave them alone because the bark is more mature?

MSAG

The bark is sweet and like candy so yes the rabbits (and other critters) will continue to munch on it. You can use the expandable plastic tree wrap - it will grow with the tree, or you can get some hardware cloth and form it into a cylinder and stake it securely to the ground - the hardware cloth won't come in contact with the tree and can stay in place for years. There are other materials available - corogated plastic that looks like drain pipe, expanded metal mesh, and more. It's worth a bit of expense and effort to save the trees and keep them healthy.

I'm no expert on fruit trees but in my limited experience if it's not rabbits it's voles and deer. We've lost a couple of trees that were too big for the white spiral tree wraps from bucks rubbing their antlers on the trunk down to heartwood. An apple tree that had been planted several years was munched on by voles. So I would keep wrapping as long as practical because the damage often cannot be undone.

You could leave one or two unwrapped and see what happens, but the damage can vary from year to year leading to a false sense of security. If you put something like metal mesh too small for voles/mice around the trunks with plenty of room for tree growth then you could leave it on and wouldn't need to re-wrap for a few years until the tree got bigger.

Cross-posted with Greene but we seem to be on the same page.

Whatever you decide, wrapping a trunk winter and summer is never a good idea. It will be a good place for diseases to breed and insects to hide. Tree trunks need air circulation for health. If you want permanent protection, use hardware cloth or something that fits very loosely as greene suggests.

I agree with Rick -- put a cage of some sort around the tree. Not all that attractive, but very effective!

Hardware cloth lets in light & air. Keeps out snacking critters.

Also helps the person using the lawnmower and weed whacker to better avoid damaging the tree bark.