Mushrooms in the Desert?

All of a sudden I started seeing mushrooms everywhere in the garden. I think it is related to the wood chip mulch that we spread around from our trusty shredder. We shredded Palo Verde wood and maybe the spores were in the wood. Regretfully, the shredder is being retired, due to neighbor's complaints about the noise. The mulch is so valuable, that I barely noticed. Oh well.