We painted our trees yesterday. No, we didn't sit outside with an easel painting landscape pictures. We painted the trunks of all the fruit trees. I bought a gallon of interior white latex paint - the cheapest gallon I could find, $10. After I bought it oldest daughter told me I should have gone to the Habitat for Humanity Restore because they sell paint for $5 a gallon. I've been told to use indoor paint because the outdoor paint may have chemicals in it that aren't good for the trees. Even so, the indoor paint will last a long time on the trees. We aren't quite done but I don't know if we will get them finished today or if it will have to wait until next weekend. We do have a lot of trees to paint! This task should have been done prior to winter but I didn't do it because I didn't remember. Nobody else around here paints their trees so there was nothing to jar my memory that this should be done.
There are several reasons to paint the trees. The first and probably most common reason is to prevent the tree trunk and bark from getting sun burned. The white (or any light color you choose) trunks don't heat up as quickly in the sun. The paint also helps prevent splitting of the wood due to temperature changes between day and night. This is something that can happen during the winter and spring, when it's warm out during the day but below freezing at night. If there is a split in the bark then the trunk under will warm up during the day then get injured by the cold at night. In the spring these areas will appear discolored and sunken. This has happened to several of my trees.
Whether from sun burn or split due to temperature changes, split bark will provide entry points for insects and diseases. The white paint is also acts as an insecticide. It keeps bugs from getting into the bark and causing damage to the tree. Also insects often will not climb the tree when the trunk is painted. This means they won't be putting their eggs in the trunk. Any bugs that are on the trunk will be more visible to birds. Ladybugs are attracted to the white trunks and they'll also help keep the tree free from bugs. There are a couple of woodpeckers around that are pecking into some of the ornamental trees in the yard. I've been told that they won't peck into the trees if you paint the trunks because they have a hard time gripping the tree. I'm not sure I believe that because woodpeckers don't seem to have a problem pecking the outbuildings at the bug-out place and those buildings are painted.
If the trees are near the road the white paint makes the trees more visible at night time. Sometimes people paint the trunks because they like the looks of it. It's best to paint the trees prior to winter but having them painted before summer will help with the sun burn even if I didn't get it on in time to help with the splitting.