Firewood question - salvageable?

I cut a bunch of trees about eighteen months ago related to a house build and department of sad compliance. They were cut into rounds and then piled. I've had many projects during that time and there was way too much wood to get to last dry season.

I've been slowly working my way through splitting the piles but nature has started doing her thing and some of the wood started growing mycellium. My question is, is it still healthy / safe to burn (for me and my stove). It's not rotten all the way through, just growing on the outside. I've planned to split and store it in the shed where it will be able to dry over a couple years but if I need to pass on these, I'll pull them out and use them for something else.

I've found wood on the ground that I missed months earlier, and looked like what you are showing.  I got mine split and stacked to dry and it was fine.  No health hazard from breathing mycellium, after all, it's going into a fire.  The only thing that is important now is to get the remaining wood completely dry.  What you might see is fungus penetrating into the wood.  If the wood is more or less totally solid still, it will be fine, as long as it gets completely dry.

You are at a good time right now because it's the height of summer, and you still have a couple of months of warm weather to get it dried before you actually need it.

Yes, defiantly usable.
That is very common, I've burned wood like that for years.
Split it stack it and let it dry.
If it concerns you take a chainsaw and just barely trim each piece.
Or just do not bring them inside until you are ready to toss them on the fire.

Thank you both! I was hoping the answer was yes and I'm so happy it was.

Too much wood to get it all moved and split this year  but I'll keep doing what I can. And I have enough dry wood already for this coming winter so this can all dry a full year after it's split.