The Pill That Cures

At least a few theories were put forward to explain the phenomena of color- changing in trees in autumn.

In the case of Momiji (maple leaves), chlorophyll is produced during summer for photosynthesis.
But this green pigment soon fades away slowly when winter approaches, revealing the yellow pigment of the leaf, which is all along hidden beneath the chlorophyll.

This phenomena is actually a preparation process for "plant hibernation", as winter day time duration and temperature condition arent favourable for photosynthesis.

Then why the color eventually turned red?

The bright red and purple colors come from anthocyanin (an-thuh-'si-uh-nuhn) pigments. These are potent antioxidents common in many plants; for example, beets, red apples, purple grapes (and red wine), and flowers like violets and hyacinths. In some leaves, like maple leaves, these pigments are formed in the autumn from trapped glucose. Why would a plant use energy to make these red pigments, when the leaves will soon fall off? Some scientists think that the anthocyanins help the trees keep their leaves a bit longer. The pigments protect the leaves from the sun, and lower their freezing point, giving some frost protection. The leaves remain on the tree longer, and more of the sugars, nitrogen and other valuable substances can be removed before the leaves fall. Another possible reason has been proposed: when the leaves decay, the anthocyanins seep into the ground and prevent other plant species from growing in the spring.

Therefore, brightest color are seen when late summer is dry and autumn has bright sunny day and cool (low 40F) nights.
(More photosynthesis in day time, and more glucose is trapped at night time)

Now, I beleive my sensei.




Picture taken in Ohara, a sleepy hollow that wakes up twice a year, autumn and spring.
Thanks to the famous Sanzenin temple, that is mentioned in a famous Japanese old folk song.


Maple leaves in Tofukuji


Evening shot in Nanzenji


A small water fall in Nanzenji