As we transition from summer to winter, the landscape is slowly changing around here. Andrew Ross of Austin was wondering what causes the leaves to change colors.
November is the peak time for fall foliage here in Texas. It is much sooner from the Rockies to the northeast early in September and October.
The color display is due to chemical processes that are altered because of the changes in day length.
In the spring and summer, the intense sun allows a food making process to take place in the leaf containing chlorophyll which gives the leaf its green color.
As the days get shorter and we see less sunshine, a hormone kicks in and slows the sap flow to the leaves. Over time, the leaf is sealed off from the branch and green chlorophyll goes away and the bright colors take over.
It doesn't have to freeze in order for the leaves to change colors. Early autumn rain followed by long stretches of warm and dry days and cool nights with temperatures ranging from 35 to 45 degrees will provide the most vivid colors. We've seen all these conditions lately plus it hasn't been rainy or windy the last few weeks so the fall foliage is lasting longer this year.
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