Question
We have 2 fruitless mulberry trees in our front yard, They are about 20ft tall and beautiful, great shade in summer. I noticed that around of the trees trunk that a lot of mushrooms are growing and that the trunk is leaking some kind of sticky substance out of it in several places and running down the tree.  I also noticed what looks like cracks in the trunk they are small and about 4 to 6" long. I'm not sure if these cracks are because we have been having a lot of wind and high heat for this region of Calif. I live in a town called Oakley, CA.  Please if you have any idea what is wrong or if this tree needs something let me know so I can take care if it. The trees are probably 20 years old, other than the leaking sap and the cracks the trees are gorgeous.  thanks, Sharron

Answer
Sounds like slime flux or wet wood.
Slime flux or Wet Wood is a foul-smelling and unsightly seepage of sap from the trunk of shade trees. It occurs in apple, birch, elm, hemlock, maple, mulberry, oak, poplar and willow. In North Carolina slime flux is very common in large, mature, landscape oaks, tulip poplar and elms. This disease is not normally a serious problem if the tree is otherwise healthy.

Slime flux is a bacterial disease. The infected wood is frequently discolored or appears water soaked (wet wood). Gas (carbon dioxide) is produced by fermentation by bacteria. The gas produces pressure in the wood. This pressure forces sap from the trunk through cracks in branch crotch unions, pruning wounds, lawn mower wounds, other injuries and occasionally unwounded bark. This oozing of sap is termed fluxing. The flux is colorless to tan at first but darkens upon exposure to the air. As fluxing continues, large areas of the bark become soaked. Many different microorganisms grow in the flux producing a foul or alcoholic smell. Various types of insects are attracted to the slime flux. If the fluxing continues for months, leaves on affected branches may be stunted and chlorotic. Grass may be killed where the flux runs down the trunk onto the grass. Sap may continue to ooze for several weeks or months, but usually it eventually stops with no treatment and no apparent damage to the tree. This slime flux may be triggered by heat, drought and other stress.

There is no curative or preventive measures for slime flux except to maintain trees in a general good state of vigor and minimize wounds and injuries. More damage can be done to the tree in attempting to cure slime flux than the flux will do alone. If there is loose or dead bark in the slime flux area, remove all of the loose bark and allow the area to dry.