The "Shoulds" and "Coulds" of Wetwood: What it Means When Your Tree Bleeds Sap

Much like humans, when trees experience bouts of stress, they weaken and become susceptible to infection. Stress comes in many forms. In Australia, summer droughts can deprive trees of water and nutrients and the resulting stress can leave the tree vulnerable for months. Likewise, injuries to roots, poorly carried out pruning cuts and injuries caused by nearby construction work can leave a tree vulnerable to bacteria.

When stressed, some tree species such as elms, poplars, cottonwoods and ash will begin to bleed sap. This condition is known as "wetwood" or "slime flux". If you have noticed that your tree is oozing sap, it is likely suffering from bacterial wetwood.

What Exactly is Wetwood?

It is thought that wetwood is caused by bacteria that gain access to a tree's core via cracks or wounds. Once these bacterial organisms enter a tree, they cause an immense build-up of pressure as they ferment the tissues in the wounded area. This pressure then causes the resulting slime to ooze from the wound.

Will Wetwood Kill my Tree?

While the slime is toxic to trees and will kill some of the tissue it comes into contact with, it generally is not fatal. If your tree has experienced considerable stress recently; however, it may begin to show signs of deterioration. It leaves may begin to wilt and die, and branches could even die back.

Is the Slime Poisonous to Animals and Humans?

Though the slime may be foul-smelling, it is not known to be toxic to humans or animals. However, you should take care if you or your children commonly relax or play in the vicinity of the tree. Pests such as bees, wasps, flies and maggots will be attracted to the slime, meaning you could be stung if you disturb the feeding insects.

You can; however, wipe away the slime each day in order to keep stinging insects away.

What Can I do to Help My Tree?

There are no known treatments for this condition. However, you can help your tree to recover by making sure it has it enough water and by fertilizing it. This will help to strengthen your tree and speed up its recovery. You should also remove the bark around the affected area to stop the slime from spreading and killing even more bark.

If you are worried about your tree and think that the condition may be worsening, call on the services of a certified tree removal arborist. Arborists have several techniques that they can employ in order to help your tree recover from bacterial wetwood, or remove it if necessary.