Lightly - As if the winds were blowing gently just as the first snow of the season began to fall. You will notice a light dusting of snow up on your green tree.
Medium - The medium look is what you'd find on trees who are covered by taller trees in the wild. Green needles can still be seen in the middle of the tree.
Heavy - After a heavy snow storm, you will see this style as you arrive at the top of the mountain. There has been a loss of definition in the needles. Most of the green around the outside of the tree has turned into white snow.