Maple trees are a popular tree planted in many Tulsa lawns and landscpapes over the past many years. Red and Yellow Maple trees grow farily fast, with a strong central truck, nice round canopy, and with beautiful fall foliage. Unlike the old Silver Maples, they have a single trunk and deeper roots that are not right on the surface. But they do have thin bark, especially when they are less than ten years old. This makes them very susceptable to sunscale injury or southwest winter injury.
Southwest injury refers to damage incurred through the killing of active cells within the trunk and limbs of sensitive trees such as Maples, Honeylocust, Crabapple, Birch, Ash, and other thin-barked trees. Young trees are most susceptible to this damage. This injury occurs when exposed bark on the tree warms up on sunny days, and previously dormant cells within the tree become active in response to the warmth. The newly activated cells lose some of their cold-hardiness and are injured when temperatures drop below freezing during cold nighttime hours. This results in discoloration and cracking of the bark. The portions of trunks and branches facing south and southwest warm the most because they get the most direct sun later in the day when temperatures are warmest.
In severe cases, the tree may die due to the damage caused to the phloem and cambium, which are the living portions of the tree just inside the outer bark. At the very least, the tree will be under stress, and with more areas where pests and disease can enter the plant. Because drought-stressed trees tend to be more susceptible to sunscald injury, make sure trees are well watered in the fall and winter even. It is very dry now in Tulsa, so it's even more important to water trees and landscapes well.
As a tree grows and matures, a thicker outer bark will develop, which will help with the hardiness of the tree. Tree wrap is easy to apply.
After planting a new tree, and for younger trees with thinner bark, I recommend a tree wrap applied every fall so that the trunk is shaded from the sunlight. Wrapping the trunks with a cardboard or plastic wrap is easy to do. It can be purchased at most local garden stores, or even the big box stores. Wrapping in the fall with a light colored wrap reflects the sunlight away from the trunk, which protects it from developing southwest injury. In the spring, the wrap should be removed to prevent garden pests from having a place to hide out.
I love Red and Yellow Maple trees, as they are an excellent selection for the Tulsa landscape. But do spend a little time to wrap them every fall while they are young, or you may be replacing it in a few years due to southwest injury. This winter especially has been up and down with the temperatures….mainly down. So expect to see alot of damage from this.