Chilly nights that stay above freezing promote anthocyanin production.įor many years, researchers have wondered why a tree would expend energy to make anthocyanin in its leaves when it’s about to shed them. Anthocyanin protects tree leaves from disease and drought, repairs leaf damage and acts as a natural sunscreen.ĭuring the fall, as the stems of maple leaves shut off from a tree’s branches, leftover glucose trapped in the leaves is used to increase the level of anthocyanin. Red in maple leaves comes from anthocyanin, an anti-oxidant that also makes reds and purples in fruits and vegetables, such as apples and beets, and in flowers, such as asters and violets. Some of those reds, yellows, and oranges have been there all along, masked by chlorophyll. Photosynthesis shuts down, and chlorophyll fades from the leaves, allowing other colors to emerge. It’s also what makes leaves look green.Īfter Labor Day, the shortening days and colder nights trigger the trees to prepare for winter. The chemical compound chlorophyll makes photosynthesis happen, allowing maple trees and all other green plants to grow during the spring and summer. Why do leaves change color? You’re already familiar with photosynthesis, the process in which leaves turn sunlight, water, and carbon dioxide into glucose (plant food) and then give off oxygen as a by-product. Read on for the facts about fall foliage… Photo © Lisa Ballard First, the basics. Legions of websites attempt to explain and forecast maple leaf color, but the best information, at least that I’ve found, is based on studies by the USDA Forest Service, the University of Vermont and the State University of New York’s College of Environmental Science and Forestry. Rural communities in upstate New York and New England depend on the economic influx that visiting leaf-peepers bring, and the vividness of the leaves are clues about changes in the ecosystem. When will the leaves begin to change? Why did that tree turn first? Why are some leaves red while others are orange or yellow? Will the colors be more vibrant this year? They are also the focus of endless local forecasting and leaf lore. Most of all, I marvel at the maple trees, which get most of the credit for the colorful show. The multi-hued landscape near our cabin in the Adirondacks takes my breath away. I treasure autumn in the northeastern United States.
0 kommentar(er)
