Slime Flux or Wet Wood

Several weeks ago, I had a very interesting home visit.  A woman told me that the sap was bubbling out of the base of her tree.  When I arrived, the sap was indeed bubbling out of the base of a mature oak tree.  It was bubbling along so quickly it made me think of a pot simmering on the stove.  There was a strong wine-grape smell in the air as well.  The sap was attracting a lot of green June beetles and an assortment of wasps and bees.  This is what I saw:

When I pried some of the outer bark off, the inner bark was soft and spongy:

After a little research, I found out that this a bacterial disease called "slime flux" or "wet wood".  Slime flux is a bacterial disease common in large, mature landscape oaks, tulip poplars and elms.  Bacteria carry out fermentation under the bark of the tree and produce carbon dioxide gas in the process.  The gas forces sap out of the bark under pressure - hence the bubbling. 

Slime flux isn't a serious problem if the tree is otherwise healthy.  These is no cure or prevention for slime flux other than maintaining trees in good health and minimizing wounds or injuries.If there is lose or dead bark in the affected area, remove the loose bark and allow the area to air dry.  Do not apply any sort of wound dressing.


You can learn more about slime flux here:
http://www.ces.ncsu.edu/depts/pp/notes/oldnotes/od8.html