When you die do you have to be buried?

I saw this forest that was used as a cemetery. They would place a body on the ground and leave it there to be reabsorbed by the forest. In Scandinavian countries they can freeze the body solid, then they shake it so hard that it becomes dust. Theres also burial at sea. Or you can leave your body to medical science where a medical student may be issued the body to learn about anatomy.