Why do deciduous trees lose their leaves in autumn?

Deciduous trees lose their leaves in autumn to conserve water and energy during the winter. As temperatures drop and daylight hours decrease, photosynthesis becomes less efficient. Trees form a protective layer at the base of each leaf stem, cutting off water and nutrient flow. The leaves change colour as chlorophyll breaks down, revealing other pigments, before falling to the ground. This adaptation helps trees survive harsh winter conditions and prepares them for new growth in spring.