Why do deciduous trees lose their leaves in the fall?
http://www.botany.uwc.ac.za/ecotree/leaves/decidu.htm
Deciduous trees lose their leaves in the fall as part of a process called leaf abscission. This is mainly driven by changes in environmental factors such as temperature and sunlight.
To understand why deciduous trees lose their leaves, we need to consider the role of leaves in trees. Leaves are responsible for photosynthesis, the process by which plants convert sunlight into energy. During spring and summer, when there is an abundance of sunlight and warmth, leaves are crucial for capturing light and producing energy for the tree.
As autumn arrives, the days become shorter, and the temperature begins to drop. These changes trigger a response within the trees. The tree begins to prepare for the upcoming winter months when conditions will not be favorable for photosynthesis.
To prepare for winter, deciduous trees start to reduce the production of chlorophyll, the green pigment responsible for capturing sunlight. As chlorophyll dwindles, other pigments in the leaves become more visible, resulting in vibrant colors such as red, orange, and yellow.
At the same time, a layer of cells called the abscission zone forms at the base of each leaf's stem. This area weakens and eventually severs the connection between the leaf and the tree. The tree then seals the open wound to prevent excessive water loss and protect against disease and pests.
By shedding their leaves, deciduous trees conserve energy and resources during the winter. Without leaves to support, they can redirect their focus towards essential processes like root development and surviving harsh weather conditions.
To summarize, deciduous trees lose their leaves in the fall as a response to changing environmental conditions, as well as a method to conserve energy and prepare for winter.