Ask An Arborist: Why is my Tree Oozing?
Q: My tree is oozing. What is it?
A: Oozing spots on the trunk of a tree can be caused by a variety of factors due to fungal or bacterial infection or attack from certain boring insects.
Careful examination and diagnosis of the associated problem is very important as these oozing symptoms can be a sign of serious issues. All to often, we find these oozing areas on the trunk of Oak trees that have suffered root damage.
The oozing lesions are the result of bleeding cankers. Cankers are the result of damaged vascular tissue most likely due to infection from Phythopthora species. Phythopthora is a fungal pathogen which typically invades the root tissue of a tree as a result of root damage. This infection moves from the root tissue up into the main vascular tissue of the trunk. As the tree tries to do its part to contain the infection, the tissue in these infected zones becomes disrupted and no longer functions properly to transport water and nutrients. The disruption of the conductive tissue within these cankers causes the sap flow of the tree to essentially create a stagnant area, which builds up with sugars creating the tar-like, sticky ooze. As infection spreads the overall health of the tree begins to decline since water and nutrients can no longer flow properly. As decline progresses the structural integrity of the tree becomes a major concern.
Early detection is key, as there is no recovering for tissue that has already been compromised by infection. The spread of the disease can be controlled through injection or topical spray applications of phosphite fungicides. High phosphate compounds can provide natural fungicidal action, as well as be extremely beneficial in promoting fine root growth.
As with any tree disease getting to the underlying root of the problem is important. Promoting overall tree health through root flare exposure, managing the biology of the soil, avoiding root disturbances, and practicing proper cultural practices is key.
-Billy Cook, ISA Certified Arborist