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=Why do Leaves Change Color= ==Every leaf of the tree is a tiny factory that works day in and day out to produce food, that is, energy. The leaf colors are due to the presence of 3 very important pigments present in the plant cell structure and parts...== [|**New Delhi**]

**The Splendor of Autumn** Every autumn we revel in the beauty of the fall colors. The mixture of red, purple, orange and yellow is the result of chemical processes that take place in the tree as the seasons change from summer to winter. During the spring and summer the leaves have served as factories where most of the foods necessary for the tree's growth are manufactured. This food-making process takes place in the leaf in numerous cells containing chlorophyll, which gives the leaf its green color. This extraordinary chemical absorbs from sunlight the energy that is used in transforming carbon dioxide and water to carbohydrates, such as sugars and starch. Along with the green pigment are yellow to orange pigments, carotenes and xanthophyll pigments which, for example, give the orange color to a carrot. Most of the year these colors are masked by great amounts of green coloring. Leaves change colors from summer to winter for their going through chemical processes,leaves transform sunlight to transform the carbon dioxide and water into carbohydrates as its food-making process. At the same time other chemical changes may occur, which form additional colors through the development of red anthocyanin pigments. Some mixtures give rise to the reddish and purplish fall colors of trees such as dogwoods and sumacs, while others give the sugar maple its brilliant orange. The autumn foliage of some trees show only yellow colors. Others, like many oaks, display mostly browns. All these colors are due to the mixing of varying amounts of the chlorophyll residue and other pigments in the leaf during the fall season. Due to the changes in the length of day and temperture makes the leaves stop their food-making process.The colors of leaves are due to the varying amounts of chlorophyll residue like how its also different colors in different trees. Most of the broad-leaved trees in the North shed their leaves in the fall. However, the dead brown leaves of the oaks and a few other species may stay on the tree until growth starts again in the spring. In the South, where the winters are mild, some of the broad-leaved trees are evergreen; that is, the leaves stay on the trees during winter and keep their green color. Other than colors of the leaves changing with the seasons is also the leaves own stems with a special layer of cells that severs the support of the leaf making it being able to easily be hit off,very rarly few leaves will stay on the tree through the winter. Most conifers dont lose their leaves for 2 to 4 years and stays greenish year-round. Enjoy the color, it only occurs for a brief period each fall. Outside influence's have a effect on the duration of fall colors,Rainy/overcast days tend to make fall colors more intense. How do we know that Carotenoids are more stable compounds than chlorophyll? For most of the year its coloring is green rather than orange like a carrot, so it can produce more food longer year-round resisting the cold more then chlorophyll does. How does nature signal it's time for leaves to change color? It starts to get colder and giving less sunlight for leaves chlorophyll to continue the food-making process. How would you explain the reason the leaves changing colors and falling off so late this year? The tempurture has not remained cold for long so the chlorophyll did not break down and stop the food-making process, also it must have been exposed to light as much as it has been in the summer making it stay on for even longer.
 * Chlorophyll Breaks Down,**But in the fall, because of changes in the length of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellow to orange colors become visible and give the leaves part of their fall splendor.
 * Other Changes Take Place** As the fall colors appear, other changes are taking place. At the point where the stem of the leaf is attached to the tree, a special layer of cells develops and gradually severs the tissues that support the leaf . At the same time, the tree seals the cut, so that when the leaf is finally blown off by the wind or falls from its own weight, it leaves behind a leaf scar.
 * Only Some Trees Lose Leaves** Most of the conifers - pines, spruces, firs, hemlocks, cedars, etc. - are evergreen in both the North and South. The needle- or scale-like leaves remain green or greenish the year round, and individual leaves may stay on for two to four or more years.
 * Weather Affects Color Intensity** Temperature, light, and water supply have an influence on the degree and the duration of fall color . Low temperatures above freezing will favor anthocyanin formation producing bright reds in maples. However, early frost will weaken the brilliant red color. Rainy and/or overcast days tend to increase the intensity of fall colors. The best time to enjoy the autumn color would be on a clear, dry, and cool (not freezing) day.