Nature is a remarkable spectacle, constantly changing and delighting us with its vibrant colors throughout the seasons. But have you ever come across trees with white trunks? It may seem unusual, but there’s actually a good reason behind it. These trees are painted white by people, and in this article, we’ll explore why.
Protecting the Bark from Sunscald
One of the main reasons for painting trees white is to shield their bark from sunscald, a condition similar to sunburn in plants. Sunscald can cause damage to the cambium layers of the bark and result in dehydration. By applying a white paint, it acts as a protective barrier, preventing cracking and minimizing the risks of sunscald.
Preventing Vulnerability to Insects and Diseases
If a tree’s bark splits, it becomes more susceptible to insects, fungus, and other diseases that can harm the tree. Painting the trunks white, especially during the winter when temperatures fluctuate between frigid nights and sunny days, helps protect the bark. This practice is often seen in residential trees or orchards with thin bark.
Christopher Evans, an extension forestry and research specialist at the University of Illinois Urbana-Champaign, explains, “Painting the trunks white is said to moderate the daytime heating of the bark and lessen the chances of sunscald injury.” 
Enhancing Visibility and Safety
Another reason for painting tree trunks white is to improve visibility, especially when they are located near roads. With white trunks, drivers are more aware of the presence of trees, reducing the risk of accidents.
Ken Fisher, assistant forester for the Boulder Parks and Recreation Department, says, “It marks the tree in an inconspicuous way and alerts our contractor that this is the tree we’re talking about.” This method has been used for many years, with paint dots identifying specific trees.
Marking Trees for Various Purposes
In forested areas, trees are frequently marked with paint to serve different purposes. It could indicate whether a tree is hazardous or safe, or simply denote private property.
Evans explains, “In some places, trees with nests of rare or endangered species are marked. 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.”
However, it’s important to note that there are no universal standards for marking paint in forestry, leading to potential confusion in interpreting different symbols and colors.
How to Properly Paint Trees
If you’re considering painting trees, it’s crucial to follow these guidelines:
- Never use oil-based paint, as it restricts the tree’s ability to breathe. Opt for water-based latex paint instead.
- Dilute one gallon of latex paint with four or five quarts of water. Look for paint with an organic base to avoid additives that could harm the plants.
- Apply the paint using a paintbrush. White is the most common color used, but feel free to choose a color that suits your taste, avoiding dark shades.
- Typically, painting the tree trunks once is sufficient. However, if you live in an area with extreme weather conditions, it may be necessary to reapply the paint once a year.
