In the past two weeks, I have been asked three times about trees with wet wounds. The foul smelling liquid ooze from wounds in the bark or wood of various shade trees is known as slime flux or wetwood.
Fluxing occurs commonly on a large number of species, including but not limited to; maple, oak, beech, birch, sycamore and willow, but elms are most susceptible.
There are two types of slime flux, brown and alcoholic, distinguished on the basis of margin, color and mode of development.
Brown slime flux originates from heart wood sap. Before reaching wounded surface, the sap is clear, watery fluid containing several nutrients. On the surface, it soon changes to a brown, slimy ooze as a result of the feeding by fungi, bacteria and insects.
Alcoholic slime flux, on the other hand, develops from the sap of bark and sap wood. It is white and frothy and usually forms near the base of the trunk. The sap is rich in starches, sugars and proteins and, thus, makes an excellent growing medium for various bacteria.
Trees are frequently wounded by extreme weather conditions in the winter in the south. The bark may split and the cambium separate from the sap wood during times when the temperatures fluctuate from 75 degrees one day and 25 degrees the next.
In Georgia, we are subject to these types of weather conditions every year.
When this happens, the wound may not be able to be observed, but the damaged tissue is invaded by bacteria commonly associated with the bark, and it begins to use the nutrients from the damaged area as a food source.
As these bacteria develop in the nutrient rich tree sap, extreme gas pressures are commonly reached up to 60 pounds per square inch. The high gas pressures frequently force the liquid to seep from the wounds and flow down the bark. This sap composed of nutrients, fatty acids, bacteria and gasses is a readily available source of nutrients for insects of various types. Bees and wasp can usually be observed feeding on the ooze.
There is very little that can be done to eliminate the bacteria from the cambium.
There have been various injection techniques researched but have not been reliable enough to recommend routinely.
In fact, injection could cause healthy tissue to be inoculated with the bacteria by disrupting the developmental tissue barrier the tree has produced.
A solution of 10 percent sodium hypochlorite (one part household bleach to nine parts water) will help surface disinfect the area around the damaged area.
This will help discourage insect attraction and help restrict damage to the bark below the damaged oozing area.
There is no control. The good news is, just because this problem exists, that does not mean the tree is in jeopardy of recovering. It just means the tree has been injured. Water the tree during droughts and do not let the tree go through any undo stress. Do not fertilize unless called for by a soil test and the tree is capable of utilizing the nutrients. Fertilizing a stressed tree improperly may cause the tree to decline further.
Clark Beusse is the Dawson County extension agent. For more information, call (706) 265-2442.