Can't hooks are nice!
Wedges work. Usually site out air pocket too under some sections, or fairly loose, so i can cut ramp in small log and pound under with sledge, to clear ground some.
i think worst is tree on ground compressed from crown to stump (seems like it fell on it's head, compression is hard to chase out), best is none of that, softly put on brush or logs to give buffer/expansion to ground concussion, and forgiveness zone when cutting.
Could cut pocket that restricts upward push and fit 4x4, or 2x8 lever into pocket as hook for lever. Place log under lever as pivot.
Cut a strong notching that restricts upward pull, low on 1 side that will catch a rope like a hook, throw over top and hook to mule (truck). Safer with 1 smooth flowing wrap around/ and or catch line for rope snap/release or 90 degree pulley redirect. Don't pull too hard, take it easy. Don't break line or be inline with it.
In all rolling over, make sure their are no restrictions to roll on forward side especially.
Cutting across slightly, doesn't feed force straight into gravity as fibre gives more gradually under less direct pull. IMHO..
:alien: