My Douglas Fir Trees Are Making Soap!

One of my favorite hashtags is #NatureAmazesMe.  Earthgirl that I am, it doesn’t take much to thrill me and turn on my wonder button when I’m out tromping in the woods, or even my backyard.

A perfect example showed up yesterday as I finished up my morning ritual and spied these clusters of foam at the base of one of my Douglas Fir trees.  I use no chemicals on or around my trees – or anywhere else, for that matter – so it wasn’t a human made chemical reaction taking place.

Since I had no clue as to what was causing this, I posted the photo on Facebook and whether anyone knew what the heck was going on with this.  One of my readers found the answer on this site.

Here’s the explanation, which I’m going to assume applies to my foaming Douglas Fir tree as well as the pines that the columnist speaks of:

“My guess is that the foam is caused by the formation of a crude soap on the bark. During drought there is an accumulation of salts, acids and other particles from the air that coat the bark surface (soap is essentially salts and acids). When it rains, these mix with the water and go into solution. The froth (foam) is from the agitation of the mixture when it encounters a barrier (bark plates) during its flow toward the ground. Another example of this phenomenon happens on pavement after long dry periods following a rain. Car tires churn up frothy foam on the freshly wetted streets after a long drought.”

So there we have it: another natural wonder solved, or at least hypothetically solved.

Unplug from the gadgets, get outside and look around.  I’m betting your wonder buttons will get pushed too.  And you will feel better.

3 thoughts on “My Douglas Fir Trees Are Making Soap!

  1. Cullen Brain

    I was reading about it because it’s happening to my Douglas Fir. It’s called slime flux and it’s a disease. Not soap.

    1. Heather Michet Post author

      Thanks for your comment, Cullen. Interestingly and thankfully, this hasn’t happened with my trees since that post! This leads me to lean toward the foaming chemical reaction vs. disease as explanation for this isolated incidence with my big Douglas Firs. My arborist does periodic “health checks” on my trees and sees no evidence of any health distress. I hope your trees are healthy too, and that this occurrence is a one-time thing.

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