Answer: My guess is that this is just a natural fungus, one of the many that are responsible, in part, for breaking down organic matter on the forest floor. There are lots of nutrients tied up in those dropped leaves and needles, and microorganisms and earthworms help convert them into forms that can be used by the trees. It's a wonderful cycle!
Mold/fungus tends to grow in places where it stays moist and dark--and the bark under those pine needles was a perfect spot. I have a feeling now that it is exposed to air, it will eventually disappear. If you're really concerned, you could scrape a sample off and bring it in an enclosed bag to a local nurseryman.
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