What has attacked my timber?

[eestere]

Spruce tongue and groove boards. Purchased in August. Have been outside, under plastic for about 3 months. These spots appear on a lot of boards, primarily at the ends.

Can I use the wood as roof decking (under roofing felt)?
Can I use the wood indoors, as subflooring for example?
Should I sand away the damage or treat it chemically?

I would appreciate it if someone could inform me about what has affected my wood.

 

[injonil]

Mold. That's what happens when boards are lying against each other with moisture that doesn't dry in time.

I think you can brush it off and use it without problems. It would probably be best if the boards were painted.