I used to wonder why some trees have white-painted trunks, and it turns out there’s a very practical reason behind it. Tree planters use white paint as a protective measure, mainly to shield trees from damage caused by harsh environmental conditions. It’s not decorative—it’s a simple but effective way to support a tree’s health.

During winter, trees are exposed to extreme temperature changes. Sunlight warms the bark during the day, causing it to expand, and then cold nighttime temperatures make it contract quickly. This repeated cycle can lead to cracks in the bark, a condition known as sunscald, which can seriously harm or even kill the tree over time.

White paint works like a kind of sunscreen. By reflecting sunlight away from the trunk, it prevents the bark from overheating during the day and reduces the stress caused by temperature swings. This helps maintain the tree’s structural integrity and keeps it healthier through the colder months.

To apply it, people usually use diluted, water-based latex paint—mixed with water so it’s not too thick—and coat the trunk evenly with a brush or spray. It typically only needs to be done once a year, making it a small effort with a big impact on protecting trees.