Fall foliage tourism across the country is a highly profitable industry, bringing $460 million annually in revenue to Vermont alone and accounting for 20 to 35% of the state's annual tourism. According to the US Forest Service, fall tourism brings $8 billion in revenue to New England each year.
Weather influences the amount and brilliance of color in autumn leaves – temperature and moisture affect color, leaf aging, and leaf death. A moist growing season followed by dry sunny days with cool nights produce the best fall colors, but varying combinations of temperature and moisture make each autumn unique. Extreme weather events can affect fall foliage in a number of ways:
- Drought stressors during the growing season, such as decreased forest productivity and increased insects and diseases, can trigger leaves to drop prematurely, before they develop fall coloration.
- Heavy winds and severe thunderstorms can cause leaves to fall before they change colors.
- Freezing conditions, especially early frost, destroy a leaf’s ability to produce red and purple colors.
- Hurricanes can destroy trees and their foliage. For example, Hurricane Irene deposited salt on trees many miles inland, causing cell and tissue damage to leaves.
- Wildfires, depending on their severity, can destroy the forest canopy.
Warmer temperatures due to climate change have delayed leaf coloring and leaf drop. Satellite observations indicate a delayed fall "changing of colors" of up to four days per decade in North American temperate forests since 1982. Warming temperatures have also been associated with earlier onset of spring – the combination of an earlier spring and a delayed fall season has increased the active growing season.
Use this illustration to identify trees and their fall foliage where you live.
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- Platt, John. 2013. Yes, Vermont Has a Leaf Forecaster. Mother Nature Network. Accessed October 1. http://www.mnn.com/lifestyle/eco-tourism/stories/yes-vermont-has-a-leaf-forecaster.
- Richardson, Andrew D., Trevor F. Keenan, Mirco Migliavacca, Youngryel Ryu, Oliver Sonnentag, and Michael Toomey. 2013. Climate Change, Phenology, and Phenological Control of Vegetation Feedbacks to the Climate System. Agricultural and Forest Meteorology. 169:156-173.
- Rogstad, Alix. 2002. "Recovering from Wildfire." Accessed October 1, 2013. http://ag.arizona.edu/pubs/natresources/az1294/
- Rustad, Lindsay, John Campbell, Jeffrey S. Dukes, Thomas Huntington, Kathy Fallon Lambert, Jaqueline Mohan, and Nicholas Rodenhouse. 2012. Changing Climate, Changing Forests: The Impacts of Climate Change on Forests of the Northeastern United States and Eastern Canada. USDA. http://www.fs.fed.us/nrs/pubs/gtr/gtr_nrs99.pdf.
- United States Forest Service. 2013. Science of Fall Colors. Accessed October 1. http://www.fs.fed.us/fallcolors/2013/science.shtml.
- United States Forest Service. 2013. "USDA Forest Service Launches Expanded Fall Color 2011 Website." Accessed October 1. http://www.fs.fed.us/news/2011/releases/09/fall-colors.shtm.
- Wiltshire, J.J.J., C.J. Wright, M.H. Unsworth, and J. Craigon. 1993. The Effects of Ozone Episodes on Autumn Leaf Fall in Apple. New Phytol. 124:433-437.