What causes leaves to change colour in autumn?

Leaves change colour in autumn due to a reduction in chlorophyll production as days shorten and temperatures cool. Chlorophyll, the pigment responsible for green, breaks down, revealing other pigments like carotenoids (yellow and orange) and anthocyanins (red and purple). The intensity of autumn colours depends on factors such as sunlight, temperature, and soil moisture. For example, sunny days and cool nights enhance the production of anthocyanins, creating vibrant red hues. This process prepares deciduous trees for winter by shedding their leaves to conserve energy.