Floor Joist "Peach Fuzz"

Came across this yesterday while inspecting a “200” year old home in New Jersey as a practice inspection for a friend of the family. Being new to the profession, I have never seen this “peach fuzz” before. It was under a porch off the ground floor of a home said to be built in the early 1800s. Have any of you come across this, what is it?
Thanks for your assistance
Cypress Grove Home Inspections, LLC






Thats just slightly weathered rough cut lumber.

Did you probe the wood or try to remove any of the fuzz? Without being there, my first guess is surface fungi (or see below). It’s funny that it’s not showing on what seems to be a large sill in the first picture, I believe. Wood from a later addition?? A different species more resistant to mould.

In some ways, it almost resembles a thick dust adhering to the joists!!

Thanks guys - I did probe, to answer your question Brian, and found it to be sound throughout. The “fuzz” is extremely soft and easily displaced, I removed some by just blowing on it. The “clean” wood looked to be a more recent repair.
Thanks again for your responses, I’m leaning toward a fungi of some sort and might try testing it. The lumber itself looks to be standard dimensional 2x6, not original to the home by any means.