The function of leaves is both to provide nourishment to the tree by photosynthesis and oxygen for animals and humans. As the sunlight wanes, properties within in the leaf produce a kaleidoscope of color, demonstrating that our Creator is also a consummate artist. God established the symbiotic relationship between oxygen breathers (animals) and carbon dioxide breathers (plants), and He also created the healing and medicinal attributes of leaves and herbs, including the Tree of Life described in Revelation 22:1-2.The righteous man in Psalm 1 is metaphorized as a life-giving tree.