Arizona Faces and Features On July 26, 1889, an American botanist arrived in the railroad town of Flagstaff, Arizona Territory. His name was Dr. Clinton Hart Merriam. He came to study the plants and animals of the southwestern United States. Hart, as his friends called him, came to seek proof for his lifezone theory. He believed that plant and animal homes were decided by the elevation of the land and the climate of that land. Elevation means height above sea level. Dr. Merriam believed that seven lifezones could be described between the equator and North Pole of the earth. He believed that all seven lifezones could be found within the Arizona Territory. Dr. Merriam defined a lifezone as a region of land where specific types of plants lived. Each lifezone was thought to contain plants that could only naturally live within that zone. The types of plants that could grow within a lifezone were dependent on four factors: 1. Type of soil that makes up the land 2. Slope of the land 3. Elevation of the land above sea level 4. Amount of yearly rain or snow that falls on the land Animals depend on plants to live. Animals live in the lifezone in which they can best find food, water, and shelter. Animals do move from one lifezone to another, but they do have a specific lifezone in which they can best live and raise their young. There are no specific lines between the lifezones. They blend together on the land. Where this blending happens, plants typical to both lifezones will be found growing. Dr. Merriam identified these seven lifezones: 1. Arctic-Alpine lifezone 2. Hudsonian lifezone 3. Canadian lifezone 4. Transition lifezone 5. Upper Sonoran lifezone 6. Lower Sonoran lifezone 7. Tropical lifezone Arizona is believed to contain six of the seven lifezones. Only the Tropical lifezone is not found in Arizona. r r r r Quaking Aspen trees in Arizona are found in the Canadian lifezone. 22  Chapter 2 • The Land