Deciduous Trees
Deciduous trees are those that shed their leaves at the end of each growing season and grow new ones at the beginning of the next. Deciduous trees are most common in the temperate lands of the northern hemisphere. They are found in a band across the northern face of the globe, between coniferous forests to the north and tropical rain forests to the south. Common deciduous trees include oak, ash, beech, elm, birch, alder, maple and horse-chestnut.
Deciduous trees have thin, broad leaves that lose water readily. Consequently, they can live only in areas where rainfall is plentiful. By dropping their leaves in winter they prevent the loss of too much water at a time when the soil is cold and water might be hard to get. Leaves are shed in the autumn. The chlorophyll breaks down and leafs green color disappears to reveal the yellows and reds of other pigments, the autumn colors. The walls of the cells where the leaf stalk joins the branch dissolve away, and the leaf hangs limply from the tree, attached only by its conducting veins. Soon, the wind snatches it away. Meanwhile, cork cells have grown on the stem side, plugging the leaf scar with waterproof material.
The kinds of trees that dominate deciduous woodland depend upon the soil. Chalk and limestone soils give rise to beech and ash woods, while acid soils are characterized by oak or birch. But no matter what kind of tree dominates, a deciduous forest almost always consists of three distinct layers, at least at some part of the year. The trees themselves form the first layer. Beneath these comes the undergrowth. This is made up of bushes and small trees. Finally comes to the ground flora of herbaceous plants.

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