The answer to the title question is that the sun is both friend and foe, depending on the circumstances. We can’t live without the sun, but we have to be careful living with it. I’m sure you know about the need for protection when you’re out in the sun.
The rush to get sun tanned has given way to the need to slather with sunscreen. Optical professionals urge us to wear sunglasses. They say the sun’s UV rays can exacerbate cataracts and macular degeneration. With these warnings in mind, it’s important to protect you, your family and even your pets but it’s also important to protect your trees, lawn and other landscape plants.
Trees and other plants depend on the sun to provide them with energy to manufacture food by photosynthesis. The big difference between our sunburn and that of trees is the amount of time it takes for symptoms to show up. We turn red immediately, but it takes a while for trees to exhibit any symptoms.
Sunburn usually occurs on young trees and thin bark trees, especially those with dark bark. Sunburn damages the tissue just beneath the bark. The bark discolors and dries out, cracks and starts peeling off. These symptoms are quite similar to those for sunscald, except that sunscald occurs in the winter and is caused by freezing. Thus, the more common name – frost cracking.
Sunburn can be caused by sudden exposure to the sun, caused by removing nearby shade, such as other trees or structures. If you’re planting new trees, try not to plant them in the heat of summer. Otherwise, take special care to protect them until they become established.
Protection measures start with watering. Be sure the tree receives one or two inches of water a week. Also, mulch and compost around the base of the tree. Organic mulch and compost will help the soil retain moisture and lower the soil temperature. Wrapping the trunk with paper, plastic or cloth, or even painting the trunk, are other protective measures.
Tree roots are intended to keep the “plant” in its place. Thus, trees do not react well to environmental changes. Sunburn is one environmental change that can be prevented or treated. But prevention is much more effective than treatment. So, consider the effect on a specimen tree before removing the shade that has contributed to its good health for all these years.
Removing shade can also cause stress to annuals, perennials and shrubs. Plants that already are in full sun should be kept hydrated and mulched. Keeping a large lawn watered will send your water bill into the stratosphere but nature equipped turfgrass with the ability to go dormant until rain and cooler weather returns. Refrain from mowing brown, dormant turfgrass. Also limit walking on it, and don’t fertilize or apply weed or insect control to it.
The answer to the title question is that the sun is our friend if we treat it with respect and take the necessary precautions to keep it from becoming our foe.