Summer Tree Stressors: Too Much Sun And Too Much Rain Can Be Hard On Your Trees

Posted on: 22 August 2017

Trees are susceptible to extreme weather conditions just like other living things. When temperatures rise and the rain pours down, there are several ways trees can be damaged.


Sunscald is caused by overexposure to sunlight. With the long days and high temperatures of summer, sunscald is something you may see on even healthy trees. Young trees or trees with thin bark are especially susceptible. Sunscald can affect all parts of a tree, bark, leaves, and fruit. The best way to avoid sunscald is to protect your tree from the sun. This can be done in a few ways.

  • Wrap cloths on the trunks and exposed limbs of young trees
  • Use white paint on nearby items to reflect sunlight
  • Avoid overpruning, which exposes too much of the tree to sunlight
  • Install barriers to block the harsh afternoon sun from reaching the tree

Sunscalded leaves are harder to avoid and can eventually be burned so badly that they turn crispy brown and drop off, exposing even more of the tree to harsh sunlight. For smaller trees, you can try spraying them with an anti-transpirant, which helps the leaves retain moisture.

Split Bark

Split bark is usually caused by uneven watering, but it can be caused by heat stressed plants that are drenched with heavy rains. The weakened bark cannot hold all the water it takes up, so the bark splits. This can leave the tree susceptible to insects and diseases that enter through the wounds in the bark. The damaged outer bark sometimes pulls away from the inner bark, making the tree unable to transport the nutrients it needs to survive.

To heal splits in the bark, you can cut the edges back to where it is still firmly attached to the tree and remove the loose bark. The wound will callus over and seal the split.

Water Damage

When you have too much rain, the soil stays saturated and the tree roots cannot access oxygen, so photosynthesis shuts down and the tree can literally starve to death once it has used up its stored starches. To make things worse, saturated soils are prime spots for anaerobic bacteria and fungi to grow, especially the fungi that cause root rot. One of the first signs of root rot is leaf loss. Mature, well established trees may survive if the soil soon dries out, but young trees may not.

If the tree is small enough, you can dig it up, getting as much rootball as possible. Wash all soil off the roots, and soak the rootball in a solution of peroxide and water for several hours, then plant it in a container in very well-draining soil. Cut back the limbs by at least 1/3 so that the roots do not have to support the entire canopy. You should soon see new growth, which signals that you can replant the tree once the soil has sufficiently dried.

Contact a business like Noble Tree Service Inc. for help taking care of your trees in summer and beyond.