Autumn leaf color is a phenomenon that affects the normally green leaves of many eciduous trees and shrubs by which they take on. During a few weeks in the autumn months, one or many colors that range from red to yellow. The phenomenon is commonly called fall colors and autumn colors, while the expression fall foliage usually connotes the viewing of a tree or forest whose leaves have undergone the change. In some areas in the United States (notably New England), and in much of Canada "leaf peeping" tourism between the beginning of color changes and the onset of leaf fall, or scheduled in hope of coinciding with that period, is a major contribution to economic activity.