Around 30 years ago I used outdoor light blue latex paint and thinned it with water.
Painted apple trees. Then began marking other trees with it that I didn’t want to disturb as I cleared some forested land.
The idea is to prevent frozen bark from expanding in winter sunlight and cracking away from the wood of a tree. So you need light colors…white being the lightest.
I’ve since ignored this advice, figuring it was only of small benefit.
A greater help is planting the same side of a tree toward the south as faced that direction in the nursery or wherever it was before planting it. The shaded side of a new plant suddenly turned into the sun plus the winter freeze/thaw and the dark color of the bark…and bark pops off or at least cracks…at a worse rate.