Science, Tech, Math › Animals & Nature A Complete Fall Color and Autumn Leaf Viewing Guide Share Flipboard Email Print Shuichi Segawa / EyeEm / Getty Images Animals & Nature Forestry Tree Identification Basics Arboriculture Tree Structure & Physiology The Science Of Growing Trees Conifer Species Individual Hardwood Species Pests, Diseases, and Wildfires Tree Planting and Reforestation Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Marine Life Dinosaurs Evolution View More By Steve Nix Forestry Expert B.S., Forest Resource Management, University of Georgia Steve Nix is a natural resources consultant and a former forest resources analyst for the state of Alabama. He is a member of the Society of American Foresters. our editorial process Steve Nix Updated September 06, 2018 One of nature's grandest color displays — the autumn tree leaf color change — will develop as early as mid-September in the northern latitudes of North America. This annual autumn tree leaf change will manifest itself in living fall color through most of October, then wane toward the end of November in the southern part of the United States. You will have at least two months of quality autumn leaf viewing somewhere in North America. The best part about viewing the fall color is, it won't cost one red cent to enjoy — that is if you are lucky enough to live in or near a deciduous forest or have trees in your yard that express fall color. All others better get ready to pay for the experience. City escapees spend over one billion dollars each season taking in what many consider the splashiest show in nature. Autumn leaf viewing is a major vacation attraction — especially throughout New England, the central Northwoods and the Appalachian Mountains of the Eastern United States. No forestry site would be complete without some mention of the October tree viewing pilgrimage — and how people can better enjoy viewing the autumn foliage. This quick leaf-viewing reference includes some basic tree leaf science and leaf viewing tips, along with enough information to enhance your next autumn leaf viewing trip. Use this guide as a starting point for your next leaf-viewing vacation. Starting Tips for Viewing Leaves Review the most beautiful trees naturally on display during fall leaf viewing season.Review these leaf silhouettes of common tree species.Get a recommended field guide to enhance the trip.Learn how to organize, build and display an autumn leaf collection.Use this field guide and key to identify an autumn leaf by tree species. The Science of Leaf Change Fall leaf color change starts very subtly late in September and early October in temperate North America. Trees respond to such factors as autumn drying conditions, temperature change, altered sun position, and light. It takes approximately two weeks to begin and complete the fall color change so timing and a little luck are essential for the "perfect" view. Fall color change and flow take place as three primary waves in mixed hardwood forests. A simple flow and wave model was designed at the University of Georgia to illustrate what leaf experts call the fall color wave. Autumn Leaf Color Change, The Anatomy of a Fall Leaf The major factor influencing autumn leaf color change is the lack of water. Not a lack of water to the entire tree, but a purposeful weaning of water from each leaf. Every leaf is affected by colder, drier, and breezy conditions and begins a process which results in its own demise and removal from the tree. The ultimate sacrifice of a leaf-bearing tree is the ultimate in visual pleasure for us. The broadleaf tree goes through a process of sealing off the leaves from the stem (called abscission). This halts the flow of all internal water to the leaf and causes a color change. It also seals the spot of leaf attachment and prevents precious moisture from escaping during winter dormancy. Fall Leaf Color Change Follows a Predictable Process of Chemical Leaf Change This lack of water to each leaf causes a very important chemical reaction to stop. Photosynthesis, or the food-producing combination of sunlight, water, and carbon dioxide, is eliminated. Chlorophyll must be renewed (by photosynthesis) or be taken in by the tree along with photosynthetic sugar. Thus chlorophyll disappears from the leaves. Chlorophyll is the green you see in the leaf. Once the overwhelming chlorophyll color is removed, true leaf colors will dominate over the receding green pigment. True leaf pigments vary with the species of tree and thus the different characteristic leaf colors. And because true leaf colors are water-soluble, that makes the color disappear very quickly after drying out. Carotene (the pigment found in carrots and corn) causes maples, birches, and poplars to turn yellow. The brilliant reds and oranges in this fall landscape are due to anthocyanins. Tannins give the oak a distinctively brown color and are the final persistent color most leaves turn before becoming part of the forest floor. The Virginia Tech Dendrology department has two fascinating time-lapse films, one on a leaf turning color and one on a forest turning into autumn gold. Viewing the Autumn Leaves University of Georgia silvics professor, Dr. Kim Coder, suggests there are ways you can predict how beautiful a fall leaf color display will be. These simple predictors use known information and apply some common sense to forecast a season with surprising accuracy. By reviewing Dr. Coder's key predictors, you will increase your chances of seeing the best leaves at just the right time. The Fall Color Hotline Probably one of the best resources available online for leaf viewing information is the National Forest Fall Foliage Hotline, though you shouldn't expect to find up to date information until late September of the current leaf season. This federal phone hotline offers you information on viewing leaves in and around the U.S. National Forests and Parks. It is brought to you by the USDA Forest Service and is updated every year to reflect changing conditions and new sites.