Depending on what kind of public land--forests, parks, game lands--the People of Pennsylvania own greatly varying percentages of the minerals under the public lands.
For example, the Game Commission owns the mineral rights for about 49% of game lands but just 20% of the mineral rights under parks are owned by the people.
80% of the mineral rights under state forests are owned by the public but just 8% of the mineral rights in the Allegheny National Forest are owned by the federal government.
Managing the surface lands and the mineral rights that are split is a key to getting right the Marcellus. Drilling in any state park and further leasing of the state forests for drilling are rightly strongly opposed by Pennsylvanians.