A restricted gauze carburetor fuel intake filter could cause lean mixture which is a reasonable match to the symptoms, but does not really explain why it would have suddenly happened when you began running the saw hard, or why it runs properly for 10 minutes before it begins to show the symptoms. I agree with Joe though, that you should check the mixture and see if making it richer improves the outcome. Even if it does seem to improve things, though, you need to look at the carburetor fuel filter, and the in-tank fuel pickup filter to make sure they are both clear.
