Why do Some Plants Lose their Leaves in Autumn?

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To survive in the cold during winters, the deciduous trees shed their leaves. They live leafless for many months, thereby conserving water and avoiding frost damage. As the temperature begins to fall at the onset of autumn, the soil gets too cold for most broad based leaves to take up enough water. To avoid further loss of water by transpiration, the trees begin to shed their leaves. The trees begin to withdraw the chlorophyll before the leaves are shed, imparting various brilliant colours to them depending upon the pigment left behind. Some evergreen trees like pine never lose their leaves even though they inhabit colder regions. They have thin, needle like leaves that have low transpiration rate and, hence very low water loss. 

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