Put thiram in some house paint and paint about a foot in height, all the way around the base of the tree.

I know from experience that a 24" fence isn't effective against rabbits when the snow is 3 feet deep. :)

A spiral tree guard wouldn't get in the way of weeding and mulching.

Luckily we don't get 3 inches of snow, much less 3 feet. I was just hoping once a tree reached a certain size the rabbits wouldn't mess with them. I'll look into other guards - thanks

I never see rabbits in winter. Even during the recent warm weather, no rabbits. also can't remember seeing rabbit tracks in the snow. I did have to add a small diameter fencing to the deer fencing I already had to keep them out of my bluesberries.

edit

Why doesn't anyone make a 5 foot high fence with a tight weave at the bottom?

Have been seeing fresh rabbit tracks in the snow everyday the past couple of weeks and it's been -25F the past three days. Going down to -32F tonight.

Rabbits are present in my area throughout the year, they are a big problem and I just don't like rabbits for the reason they damage my pear trees, quince trees, and any other trees / plants.