What is Sunscald?

What is Sunscald?

What is Sunscald? Sunscald is a form of winter damage that can affect trees in Wisconsin. It occurs when bark freezes following extreme cold temperatures in the winter season, resulting in permanent visible damage to the bark. 

• What causes sunscald 

  Sunscald occurs during late winter when there are significant temperature changes, like warm days followed by cold nights. The sun warms the bark, which stimulates activity, and then a sudden drop in temperature happens when clouds or buildings shade the area.

• Signs of sunscald

   Sunscald manifests as dry, cracked, sunken, or elongated patches of dead bark, typically found on the south or southwest side of the tree.

   
• How to prevent sunscald

  To prevent sunscald, you can:

  • Water your tree deeply until the ground freezes. Hydrated trees are less likely to experience sunscald. 
     
     
  • Mulch your tree in the fall to retain moisture. 
     
     
  • Cover the trunk with a tree guard or wrap it in Kraft paper to protect the bark from the sun. Remove the wrap in the spring. 
     
     
  • Plant shrubs or smaller plants on the southwest side of the tree to shade the bark. 
     
     
  • Choose cold, hardy plants for your area and well-suited to the local growing conditions. 
     
     
• How to treat sunscald

  Don’t paint or seal damaged areas, but allow them to heal naturally. You can use a knife dipped in a 10% bleach solution to trim away any excess bark.  With good care, trees survive, but the trunk is disfigured for years, and the open wound can be the source for borers or a hollow tree later in the tree’s life. Preventing sunscald injury means paying special attention to watering during the first few years of establishment for young trees