Autumn is the perfect time to enjoy the District's outdoor treasures and catch a glimpse of natures splendor seen by our Nation's Founding Fathers. George Washington and Pierre L'Enfant masterful design strategy provides breathtaking open public landscape painted with a mosaic of warm toned shades of orange and gold to purple and scarlet. Autumn's crisp chill and diminishing length of daylight induce trees to shed their green leaves. Temperature, sunlight, and soil moisture greatly influence the quality of the fall foliage display. Before leaves fall in the autumn they pass key nutrients, such as nitrogen and phosphorous, back into the main body of the tree or plant. Species with brighter autumn leaves appear to retain more nutrients than duller-coloured ones. Two pigments play a vital role in this process: Anthocyanins and Carotenoids. Anthocyanins are water-soluble red, rarely blue, pigments found in both the young and old leaves of many plants, while Carotenoids are highly unsaturated fat-soluble yellow-red pigments produced by plants and fungi.
Thomas Jefferson Memorial during Fall season. *
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View of Washington Monument during Autumn. *
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View of Rosslyn from Tidal Basin in Washington DC.
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Autumn leaves of a Northern Red Oak living near the Thomas Jefferson Memorial. Fall weather conditions favoring formation of brilliant red autumn color are warm sunny days followed by cool, nights with temperatures below 45o F.
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Fall leaves of a Northern Red Oak. Change for green to bright red.
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Autumn cherry blossom leaves. Washington Monument is in the background.
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Autumn oak leaves. Much sugar is made in the leaves during the daytime, but cool nights prevent movement of, sugar from the leaves. From the sugars trapped in the leaves the red pigment called anthocyanin is formed.
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Autumn view of Washington monument from tidal basin.
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Autumn view of White House from tidal basin. *
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Kids running around Tidal Basin.
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The Yoshino cherry tree leaves are ruby-red. Thomas Jefferson Memorial in background.
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Yoshino cherry tree foliage.
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Yoshino cherry tree foliage.
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Wed Nov 14 13:07:43 2007
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Yoshino cherry tree foliage surround Japanesse lantern.
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