Cankers are dead sections of bark, branches, or trunk on a tree.  They are among the most destructive and hard to manage tree problems as they attack a tree’s tissue cells and cause decay.

Most canker diseases are caused by fungi that grows between the tree’s bark and the wood killing the living portion of the bark.  Fungus usually enters the tree through an open wound caused by stress, such as drought, flooding, extreme temperatures over an extended period of time, high winds, chemical injury transplant shock, improper pruning, or mechanical injury from lawn equipment.  Fungus may also enter the tree through a natural opening, such as the tiny openings on the underside of leaves.  In some cases, canker disease can be caused by bacteria.

While a healthy tree will respond to injuries quickly and form a defense barrier to halt expansion of a canker, stressed trees are unable to form such a defense and as a result, cankers spread rapidly.  Cankers themselves make a tree more vulnerable to fungus and bacteria, and thus more cankers, further undermining the health of the tree.

tree cankers disease on a tree


Cankers are essentially “sores” that appear on the branch or trunk of a tree and kill woody cell tissue in a localized area.  Depending on the type of canker, size and shape may vary, though cankers often start small and grows larger over time.  As they grow, they kill the water and food conducting system resulting in dying or dead branches, discolored or lost foliage, and dark or discolored bark that appears sunken in. Cankers can cause extensive damage to a tree when they kill all of the bark in a particular area as girdling, the death of everything above the canker results.


Cankers are very difficult to treat.  Depending on the location and extent of the canker, it may be possible to remove only the affected area of the tree, though in many cases tree removal may be necessary due to weakened structural integrity caused by the cankers.  There is no chemical treatment for canker disease.

black mark on a healing tree trunk


The most effective strategy against cankers is to prevent them from occurring.  Cankers are most common on trees under stress as weakened trees are much more susceptible to cankers.  The healthier a tree is, the more likely it is to ward off damage from a canker.  Thus, proper tree maintenance is important as it can reduce the risk of canker diseases.  Regular inspections and pruning by a Certified Arborist, as well as proper watering and soil management, can help ensure a healthy tree.


If you think your trees are suffering from canker disease, contact Jake at TREES BY JAKE to take a look at 918-500-9955.  Jake is a Tulsa Certified Arborist with over a decade of experience in the Tulsa tree care industry and can recommend the proper steps to take, including tree trimming, removal of dead wood, or tree removal.

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TREES BY JAKE has been providing tree removal services in Tulsa for over a decade. Jake is a Tulsa Certified Arborist and we have a variety of equipment to safely and efficiently remove trees. Call or text us today for your free estimate at 918-500-9955 and don’t forget to check us out on FacebookInstagram, and Twitter!

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