There are many species of pine trees that have pine nuts in them. My local trees are Jeffrey Pines which are a cousin to a sugar pine. Before attempting this at home, I strongly suggest researching your local pine trees to ensure their pine nuts are edible!
I also take the laziest approach possible, which isn't all that lazy because this is time consuming! As I'm walking around town, let's say with my dogs, you usually see pine cones on the ground, having fallen from trees. Sometimes you will notice these pine cones are not yet open. When this happens, I pick it up and put it into a bag and take it home.
Now, these closed pine cones are hella hard to open. So I don't even try. I leave them in the bag until they dry out and start to open.
|Throwing against the pavement|
|liberated pine nuts with their wings still attached|