Jonathan Goodish wrote:
I am a relatively new chain saw owner who has Googled extensively and
read the owner's manual several times. I have a good degree of common
sense, and try to take care, but I am destined to make stupid mistakes
anyway.

After about 2 hours of use on the new saw going through cherry and
ash, I started into some oak about 12" in diameter with a 20" bar on
a Husky 346XP (fast saw). I worked through this for about an hour
and noticed that the the oak seemed to be getting progressively
harder to cut, requiring more pressure on the saw as I moved toward
the base of the tree (tree had been felled already).

At this point stop. Your chain is dull.

Keep in mind if you get the chain in dirt it will almost instantly dull the
chain.

The teltale sign of chain health is the chips put off. They should be large
shavings; when they become fine dust the chain is dull.

The bar is probably fine; the chain may have been fried though. If the
teeth are blue they have been overheated.

Buy and learn to use a chain sharpener; I have a dremel attachment which
works GREAT.