I have a 2001 Subaru Forester. It squeaks loudly when I first start it in the...

...morning.? It also squeaks when I turn the wheel all the way to the left or right, and sometimes when I go straight. The squeaking lasts about 10 seconds. Anyone know what it could be?

First of all, congrats on being an owner of a subaru, to me they are a very relyable vehicle.
In your situation it sounds like you have a lose belt, most likely the one on your power stirring pump,belts get lose over time and ware out, this is part of regular maintainance you can tighten it up or best just replace it. A lose or wore out belt will squeal on first startup and turning the wheel, even stepping on the gas peddle(reve up or taking off fast) will cause this niose just take it to a repair shop or do it yourself, it's easy to do...trust me...hope this helps