Slime flux, also known as bacterial wetwood, is a common tree condition that often concerns homeowners due to its unusual appearance. This phenomenon involves a liquid oozing from tree trunks and branches, leading many to question if it poses a danger to human health. This article explores the nature of slime flux, its impact on trees, and whether it presents any risks to people or pets.
What is Slime Flux?
Slime flux manifests as a discolored, frothy liquid seeping from cracks, wounds, or branch crotches on trees. This ooze can be clear initially, but it turns brown or black upon exposure to air. The liquid results from bacterial fermentation within the tree’s internal wood, producing gases and a foul, fermented odor.
The underlying cause is a bacterial infection, involving various bacteria, which thrive in low-oxygen environments inside the tree’s inner wood. These bacteria enter through wounds, like those from pruning, insects, or environmental stress. As the bacteria ferment tree sap, they generate pressure, forcing the liquid out through openings in the bark.
Is There a Human Health Risk?
Slime flux poses minimal direct health risks to humans. While the appearance and odor can be unpleasant, direct contact with the oozing liquid is not harmful. The bacteria involved are common in soil and water, but they do not readily transmit to humans or cause disease through casual exposure.
Exposure to the liquid can cause mild skin irritation. The strong, foul odor, alcoholic or sewage-like, is a byproduct of fermentation and is not considered a health hazard through inhalation. Insects like flies, wasps, and beetles are attracted to the ooze but do not spread the infection to humans or pets. Individuals with severe allergies to bee or wasp stings should be cautious near affected trees, as these insects may gather around the flux. Pets, especially dogs, may be attracted to and consume the flux, but significant health issues are not commonly reported.
Managing Slime Flux Safely
While there is no cure for the internal bacterial wetwood infection, managing slime flux involves promoting overall tree health and safely handling external oozing. Maintaining a tree’s vigor through proper watering, fertilization, and avoiding injuries can help it naturally compartmentalize the infection. Promptly addressing wounds from pruning, lawn equipment, or storms can reduce entry points for bacteria.
If physical contact with the slime flux is unavoidable, wearing gloves is a precaution to prevent skin irritation. Washing any residue off the tree with a gentle spray of water can improve its appearance and minimize its effect on bark or underlying plants, but care should be taken to avoid spreading the ooze to other vegetation. Historically, drilling holes to drain the flux was common, but this practice is now discouraged as it can further spread bacteria and harm the tree.