Tony’s Weather Blog–Foliage Update
Signs of Autumn are all around us and that includes some trees already changing color in Northern New England with some splashes of spotty color here in our area. On average, peak colors occur around Columbus Day Weekend (2nd week of October) in Northern Maine, New Hampshire and Vermont. Southern N.H., Vt., ME is usually around the 3rd week of October, including the Berkshires. Finally in southern New England around the 4th week of October.
What make the leaves change color? The really don’t change color but rather reveal colors that are already there, hidden within deep pigments of green….As the green disappears, other “hidden” colors show up. Plants absorb water from the ground through their roots. They also take in carbon dioxide from the air, while using sunlight to turn water and carbon dioxide into glucose. Glucose is a kind of sugar. Plants use glucose as “food” for energy to help them grow. The process of plants turning water and carbon dioxide into sugar is called photosynthesis. A chemical called chlorophyll helps make photosynthesis happen. Chlorophyll is what gives plants their green color.
So….how do we get rid of the green colors?? That’s where the change of seasons comes in. As summer ends the days get shorter with less sunlight. During the winter, frozen soil means less water getting to the roots. As a result photosynthesis shuts down….green colors fade, revealing pigments of yellow and orange. In some trees, like maples, glucose is trapped in the leaves after photosynthesis stops. Sunlight and the cool nights of autumn cause the leaves to turn this glucose into a red color.
You can try this link for updates on color across New England the next several weeks:
http://www.yankeefoliage.com/
Our weather team will keep you updated…check back with us on wpri.com for more info.
Tony Petrarca

