How rain in CNY is affecting fall foliage, plus the chemicals that cause color changes

SYRACUSE, N.Y. — Fall has officially begun as of last Sunday and signs of fall are beginning to show in the trees across CNY, especially the higher elevations. What causes the leaves to start changing color, what chemicals cause certain colors, and how does the weather affect the brightness of the colors?

When the weather starts to get cooler, the tree’s chlorophyll breaks down, leaving other chemicals that cause color changes. Chlorophyll is what causes a green color in the leaves, xanthophyll is responsible for the yellow color, carotene causes an orange color, and anthocyanin creates a red color.

The brightness of the colors is determined by the weather. Brighter colors are more likely when late summer is dry and autumn has sunny days and cool nights. This is because a rainy early to mid summer helps the leaves to grow, then a dry late summer to early fall with more sun allows sugars to be produced in the leaves that cause colors. Cool nights shrink the veins in the leaves trapping the sugars inside after the sun goes down at night and the leaves stop producing sugars.

This season is looking good for fall foliage as we had a rather rainy summer, but a dry late summer to early fall. The monthly rainfall total in Syracuse for August was 7.62 inches, which is nearly 4 inches above normal. Then in September so far Syracuse has only seen 1.31 inches of rain this month. This is 1.38 inches below normal for September.

Here’s some other leaf fun facts! On a mature oak tree there is an average of 200,000 leaves. Around 360 dry leaves is equal to 1 pound of weight. One tree has about 550 pounds of leaves when they are dry. Wet leaves can multiply that weight by about 4 times!
For the latest fall foliage report, CLICK HERE!