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Nature Notes: Mother Nature’s fall fanfare

By Kelly Bahl

Teacher/Naturalist Intern

When people think of fall, many different thoughts run through their heads. There are thoughts of cooler weather, sweaters, bonfires, apple orchards and pumpkin spice everything. Even the natural world partakes in fall festivities. One of the favorite telltale signs of fall is the show that trees put on when their leaves change color. Have you ever stopped to ask yourself why?

Leaves are green because of little tiny things called chlorophyll inside the plant cell. The chlorophyll is what is in charge of the process of photosynthesis, which makes food for the tree. When light shines on the leaf and enters the chlorophyll, red and blue light get absorbed. Green light reflected off the chlorophyll makes the leaves appear green. By fall, the trees have stored a bunch of food so it does not need to make any more for the season. When fall approaches and daylight hours shorten, photosynthesis stops and the chlorophyll disappears, leaving behind certain pigments in the leaf to show off the fall colors we all come to expect.

The base colors for most leaves are yellows and oranges. However, the brilliance and vibrancy of the leaves depends on current and past weather conditions. 

If there is cool air at night, but not freezing, with days full of sunshine, the trees will show more red and purple pigments. Weather that is too cold with freezing conditions early into fall will end the colorful foliage abruptly. The best weather for bright varying colors of leaves requires ample moisture during the growing season, followed by cool and dry weather in late summer and early fall along with a lot of sunshine. Since there can be countless possibilities of what the temperature and moisture levels can be like in any given year, that means that no two autumns will ever look the same.

This autumn we have seen the tree colors starting to peak slightly earlier than the past couple years. If you want to see the brilliant show this fall season has in store for us, get outside and explore before it is too late!

Upcoming Events

• Oct. 9-10: 37th Annual Halloween Warm-Up, 6:30-9:10 p.m. Tickets for sale at Jim’s Super Fresh Produce, more information on our website: hormelnaturecenter.org

• Oct. 17: Archery Deer Hunt begins at Nature Center; Sola fide Observatory Night, 8-10 p.m. RSVP only. Check the website for more information.

• Nov. 2: Registration begins online for Christmas Crafts class, 9 a.m.