One of the Moons in the heavens, it represents the forces of Life and Natural Magic. It cycles on a rotation of 11 years, 11 months and 11 days or every 3872 Days.
During the three days of a Green Moon, natural magic (druidic and the magic of witches) is at its most potent. The potency of all natural spells is doubled during these three days as is the range and duration. A simple healing spell, for example, will heal for double its normal limit. A ranged spell can be cast at double the distance without penalty and a boosting spell will have double the duration.
Whenever a green moon appears in the sky it is called a Green Year.