Menu
Wood Decay in Trees

Wood Decay in Trees

, , , ,

Wood Decay in Trees

 
Wood decay in trees is a process caused by fungi and bacteria that break down wood, leading to reduced structural integrity and potential failure. Key types of decay include white rot, which makes wood soft and spongy, and brown rot, which causes brittle, crumbly wood. Decay typically starts at entry points like wounds from construction, logging, or lawn equipment.
 
Types of wood decay
  • White Rot:
    This decay is caused by fungi that break down both cellulose and lignin, leaving behind a soft, stringy, or spongy material that is often a light color.
  • Brown Rot:
    This type attacks the cellulose, leaving the wood with a brown, brittle, and crumbly texture
  • Soft Rot:

    Caused by fungi and bacteria, soft rot breaks down cell walls and materials, though it is generally a slower process than white or brown rot. 

     
Common causes and entry points
  • Wounds:

    Decay fungi primarily enter trees through wounds, which can be caused by construction, logging machinery, or even routine lawn care like mowing and trimming, notes Ever-Green Tree Care and this University of Kentucky document. 

     
  • Root grafting:

    Root rot can spread from one tree to another through root grafting, leading to a dieback of the roots. 

     
  • Moisture:

    Fungi that cause decay require prolonged periods where the wood’s moisture content is high (typically above 20−25%

    20−25%). 
     
  • Buried wood:

    Wood that is buried or covered by soil changes, like with grading, is more susceptible to decay because the bark barrier is broken. 

     
How to identify decay
  • Swelling:

    A swelling or “bottle butt” at the base of a tree can indicate that the tree is responding to internal decay by forming reaction wood

     
  • Fruiting bodies:

    The presence of fungi, such as mushrooms, on the trunk or at the base of a tree is a direct sign of a decay-causing infection. 

     
  • Changes in wood texture:

    Decayed wood will have different properties. White rot makes wood soft and spongy, while brown rot makes it brittle and crumbly

     
  • Cavities:

    While not all cavities are a major problem, large ones can indicate a significant amount of internal decay. 

     
What to do
  • For minor wounds:

    Often, the best course of action is to do nothing, as the tree can seal over a small wound on its own, says The Morton Arboretum. 

     
  • Prevention:

    Avoid damaging trees with lawnmowers and string trimmers, and take precautions to minimize damage during construction. 

     
  • Professional assessment:

    For extensive decay or large cavities, it is best to consult a professional arborist for a diagnosis and to assess the risk of failure.  

     
    Contact Johnson Ops Tree Care for a PHC evaluation of your trees. One of our Certified Arborist would be glad to meet with you  and discuss your trees and get a plan  of action if needed. 
 
Share this:

Related Posts