CODIT: How Trees Heal Themselves

Compartmentalization Of Decay In Trees” or CODIT for short, is a concept that was created by Dr. Alex Shigo, an American biologist and Plant Pathologist, in the 1970s.  The concept is now widely referred by, and used within the Arboriculture Industry, and referenced in other publications.  It is, in a nutshell, the concept that when trees are wounded or injured, many organisms decay the wood, in different ways and timeframes.  Further, It is how the tree responds through chemical and physiological changes and “Compartmentalizes” the wounded or injured area to prevent ongoing decay and spread to the rest of the tree. The cells in the area of the injury, in essence, form “protection” to isolate the decay from the rest of the tree.

The tree does this by the process of activating specific cells to form 4 “Walls” of protection.  The first “Wall” is the weakest, but it forms to stop the vertical spread of the decay, up through the tree’s trunk or branch.  “Wall” 2   stops the outward or horizontal spread of the decay.  The 3rd “Wall” is the second strongest wall, and creates a “maze-like” barrier internally near the injured area.  The 4th and final “wall” is the strongest barrier which is produced on the exterior of the tree, by closing the wound with new wood.

By understanding how your tree “heals”, a deeper comprehension and connection can be made when discussing your trees’ health with your Tree Care Professional.  Your Edmonton Arborist can help you further understand the information regarding CODIT, with full understanding of this healing concept and how your tree will respond to protect itself.   

Tree Growth Rings: The Story They Can Tell

“Growth Rings” of trees or “Annual Growth Rings” are concentric circles of new cells which a tree produces during one growing season.  A tree gets larger in diameter because it manufactures new cells around it’s circumference.  The tree’s annual rings are biological indicators which can reveal environmental events that have occurred, over a tree’s lifespan.

By looking at a cross-section of a tree’s stump or log, one can visibly see rings that can tell a story of what the growing season was like many years in the past.  A good growing year, with warm, wet weather, will produce wider concentric circles, while dry, cooler years will produce narrower ones.

Forest fires, insect infestations and even distant volcanic eruptions, have been recorded within the rings of ancient trees.  In Canada, which has a distinct winter dormancy season, growth rings are used to calculate an accurate age, of trees.  The scientific method of dating tree rings, is known as “Dendrochronology”, which has been used to date some of Canada’s oldest trees.