Answer: Some trees are especially prone to sunscald and frost cracks so gardeners will try to protect the bark by painting it white to reflect the sun, or by wrapping it to shade it during the winter. Maples -- including Japanese maples -- would be in this group. In my experience, using a tree wrap is better because the white paint really stands out in the landscape. White paint is used more often in orchards than on ornamental trees. Be sure to remove the wrap in the spring.
Your Japanese maple would also benefit from a year round layer of organic mulch about two to three inches thick, apply it in a flat layer over the root area and do not allow it to touch the trunk of the tree. If it is in a windy location, you might also consider giving it a wind break of some kind.
Here is more information about winter protection you may find interesting. You may need to cut and paste the complete url to make it work correctly.
Enjoy your trees!
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