If they're actually tangled in the roots, I'd just cut them off below grade.

Push them back and forth in all 4 directions for a few mins using all your weight to widen the hole its in, should pull out then.

^^^ This might be good advice given the user name.

Wrap a chain around them and lift 'em with a hi-lift jack.

I have cleared old fence lines with t-post around red oak, white oak and hickory trees that were old trees and never hurt the trees, don't know about young trees.
You can use a chain and an older car bumper jack or high lift jack.
Or the easiest is a decent size tractor with a front end loader. Just double hitch the chain toward the bottom of the post and the other end hooked to your bucket.
Lift it slowly. If it doesn't come out easy then back up a little then forward a little as you are keeping up pressure on the post.

I use one of these. Makes it fast and simple if you have lots of t-post to pull….especially if you have a tractor or skid steer.