![](https://i.imgur.com/1aMrdKA.jpg)
and
![](https://i.imgur.com/SxAa2q9.jpg)
With all the rain we have gotten this spring (this is in Austin), the mulch bed around a smallish Monterrey Oak always produces these small white bubbles that eventually turn gray and go away...then another rain hits and they come up again. I also noticed the larger brown mushrooms near the trunk.
a) are they harmful?
b) how do I get rid of them?