So how or more appropriately, why does the green leaves of summer turns to yellow, orange or red during autumn? We know that leaves have the green pigment chlorophyll used in the production of plant food (glucose). Leaves also has the yellow (carotenoid pigment) and red (anthocyanin pigments) but is not seen much because they are covered up by chlorophyll. The leaves know that it is autumn when the days become shorter and shorter, since ‘photosynthesis,’ the process where plant makes food happens with the help of light.
As for maple trees, persimmons and other red colored leaves, the leftover foods plus the (occasional) sunlight and cool breeze of autumn makes this wonderful color comes out.