MASON CITY – As summer winds down and school is now in session, things outdoors are beginning to go through changes. One of the most beautiful and brilliant changes is that of leaves. There are many ideas as to why leaves change their colors in the fall from the wide temperature range between day and night, to the soil’s acidity, or even the incoming frost; all are true in one way or another.
Chlorophyll, the compound that helps plants produce their own food, is responsible for giving the leaves their green color. As we move into fall, chlorophyll levels within the leaves begin to decrease revealing other pigments that are present. These other pigments help with energy absorption. Their levels within leaves is dependent on various factors such as tree species, mineral availability, and soil acidity. These variations result in the range of colors we see driving along the road or hiking trails during fall. The colors can range from bright red hues of the hard Maples to yellows of the Elms and Bur Oaks.
We see these color changes due to the tree preparing for winter dormancy. When the nights reach a certain length, the plant releases a chemical called phytochrome which tells the plant that it is time to get ready for winter. The weather plays a large role in the development of the colors in the leaves. Colder temperatures at night destroy chlorophyll faster resulting in a quicker change, but if it gets too cold there won’t be much red pigment. During cloudy days and warmer nights, the colors are less bright due to the slower breakdown of chlorophyll. When it gets dry out, the leaves become a brighter more vibrant red due to a build up of sugars within the leaves allowing for more red pigment production. Finally, windy and rainy weather will result in leaves falling off too early and now providing that breathtaking display of colors.
Here in Northern Iowa, the colors will go through this change from the last week of September to the second week of October. For a beautiful day of exploring the brilliant colors of fall that Cerro Gordo County has to offer we suggest following the route below! For more information about fall colors, you can visit our website by going to www.cgcounty.org, clicking the departments tab, and click Lime Creek Nature Center under the conservation tab; or give us a call at (641) 423-5309.
Article and photos from our Conservation Education Intern Emma Jacobs