What Is Fall Season

The hallmark of the season is the changing color of deciduous foliage. During spring and summer, leaves appear green due to the dominance of chlorophyll, the pigment necessary for photosynthesis. As autumn progresses and daylight diminishes, trees cease food production in preparation for winter. Chlorophyll breaks down, revealing underlying pigments—xanthophylls (yellows) and carotenoids (oranges)—that were previously masked. In some species, such as maples, the stress of autumn triggers the production of anthocyanins, resulting in brilliant reds and purples. This senescence (aging) leads to the abscission layer forming at the base of the leaf stem, eventually causing the leaf to fall.

The season is defined by three key natural events: what is fall season