foaming tree?

We had a rain storm come in last night. Rained all night and a good part of today. As I was walking around making sure no branches fell on any of my plants, I noticed a tree had a bunch of foam/bubbles at the base of it. It appeared that water was running down the trunk and then foaming out of several locations and pooling at the bottom. Any clue what this could be?
Thanks,
Kristen

It could be something very simple,but here is an interesting article.
The foul-smelling and unsightly seepage of sap from the trunk of shade trees is commonly called slime flux or wet wood. It occurs in apple, birch, elm, hemlock, maple, mulberry, oak, poplar and willow.

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 up 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.

Large mature landscape oaks have had problems with slime flux on the trunk or large exposed flare roots just above the soil line with no apparent wounds or injuries. 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. Do not apply a wound dressing.

Slime mold is a sort of tan looking foamy growth that at first appears like a pet or small animal has barfed. I have had quite a bit this year, with all the rain, and have read of others with it, too. It's pretty harmless from what I gather. You can wash it away with a hose, or let it dry and blow away.

Do you spray your trees with anything? I use soap on my fruit trees sometimes and the next rain will cause bubbles. Just the soap washing off. Oils can do that too.

Not real sure what you mean by foam.

Sorry all and thanks for the responses. I've been off DG for a few days. I'm going to have to look up the slime stuff and see if that looks like what I saw. We just moved to this house recently and we haven't sprayed the trees, but I can't speak for the former owners. It did look like soap bubbles but seemed to be bubbling out of the tree as the rain water ran down the trunk of the tree. It's an oak tree, if that makes a difference. I just realized, I didn't state that earlier. We have some trees here that look to be in pretty bad shape and just had a storm bring down a giant oak tree on our old house (after we moved out). Tree looked ok from the outside, but when they cut it up, it was nothing but muddy looking ooze inside of it. As you can imagine, I'm looking at everything now wondering if it's healthy all the way thru or rotten inside and going to come down with the next storm.

I've had something similar with a Jacaranda tree. It was topped or broken when it was 2 ft high; made several trunks. There's still a dead area in the center where the water was collecting. It did see it bubbling seeping out the side. There's been no evidence of slime or mold other than the bubbles while it was raining.
We're cutting the one trunk that might fall on the house if a himmi/hurricane gets closer.