Why Are Some Trees Painted White?

Nature is full of vibrant colors. Trees alone boast a wide spectrum of shades, from pink cherry blossoms to deep green pines to yellow maple leaves. However, some trees have white bark — not naturally like birch trees — because of human-done paint jobs. This isn’t a trend to make the trees look cool; after all, no amount of paint can one-up the inherent artistry of nature. Instead, the paint is used to protect trees while they develop.

Why Are Some Trees Painted White?

You may have seen trees’ lower trunks painted white. This is to protect the bark from sunscald, which is basically the plant version of sunburns. It commonly occurs in the winter where fluctuating temperatures from chilly nights to sunny days can damage the bark. So the light color protects the tree from overheating and prevents the bark from cracking. Splitting bark opens up the tree to disease, fungus, and insects that could infest and further harm the tree. [1]

“This type of painting is typically done on thin-barked residential trees or orchards,” says Christopher Evans, extension forestry and research specialist at the University of Illinois Urbana-Champaign. “Painting the trunks white is said to moderate the daytime heating of the bark and lessen the chances of sunscald injury.” It’s only needed for young trees until they grow stronger and less susceptible to changing temperatures. [2]

More Reasons for Paint on Trees

You might have noticed trees around your home with different paint jobs. While white protects bark, other colors and patterns indicate instructions for people. For example, some trees bear marks to show that they are diseased, must be chopped down, or require pruning.

“Basically, it marks the tree in an inconspicuous way,” says Ken Fisher, assistant forester for the Boulder Parks and Recreation Department. “A lot of people don’t even notice it, but it alerts our contractor that this is the tree we’re talking about. We’ve been using paint dots for 25 years or so now, so some trees have several paint dots on them.” However, cities keep individual codes, so a red or purple dot might mean different things depending on the area.

If you enjoy forests and nature trails, you may have come across another set of paint jobs. They can indicate which trees are hazardous or safe. They may also mark private properties hiking trails, or indicate details about the environment. “In some places, trees with nests of rare or endangered species are marked,” says Evans. “That is the case with the federally endangered red-cockaded woodpecker in the Southern United States. Their tree nests are generally marked with a white paint ring.”

But remember to check the guidelines of a specific area before making any assumptions. “Basically, there aren’t any hard and fast standardizations for the use of marking paint in forestry,” Evans says. “That can lead to confusion when trying to generalize the meaning of different symbols and colors.” However, some are more universal. For example, an X often means the tree should be cut, and numbers show a tally before a harvest. In many states, purple paint marks private property.

How to Paint Trees White

Keep in mind, that painting young trees white is a long-used method of protection, but some experts question its effectiveness. Yes, the paint can help prevent young bark from overheating, but the wrong kind of paint can severely damage the plant. Therefore, it’s important to choose the right product, which is water-based latex paint diluted to the ratio of one-gallon latex with four or five quarts of water. You may also want to use a rodent repellent to prevent rabbits and other animals from gnawing on the trees. 

Do not use oil-based paint since this will lock in the bark and prevent the tree from absorbing oxygen. Also, look for paint with an organic base to avoid additives that could hurt the plants. And it doesn’t have to be white; any light color will work, but be sure to avoid darker shades that will take in extra heat and worsen the sunscald.

Now that you have the ideal paint mixture, use a paintbrush to apply it. Sprays don’t stick to the bark as well and don’t provide enough protection. And don’t worry about a perfect paint job. One coat should work unless the weather conditions are severe. Additionally, if you live in areas with extreme weather, you’ll need to reapply the paint once a year. But overall, white paint is an easy and effective way to protect young trees as they grow taller and stronger. [3]

Keep Reading: If You See a Painted Purple Fence, This Is What It Means