Fall Time Foliage

Right now, it is amazing to look outside and see all the splashes of red, yellow, orange, and green that the trees are providing us with. This beautiful scenery is one of the multiple reasons living in the country in Indiana is great.  Yet the question does remain, what causes leaves to change into various shades of red, yellow, and orange? 

Chemistry is the driving force behind the leaves changing colors. Throughout the summer, chlorophyll gives leaves their green color and is essential in the photosynthetic production of food needed by the tree. Once the days grow shorter and temperatures begin to fall, chlorophyll production slows down. At this time, other pigments begin to appear giving leaves their brown, red, orange, purple, and yellow hues.  

The color the leaf takes on depends on which chemical is more prominent: anthocyanin, carotene, xanthophylls, or tannin. It is never completely certain which chemical will be more prominent but tannin, in particular, is more prevalent in the brown to dark red leaves of oaks, walnuts, and hickories. When the leaves do start to change colors, the outer margins of the leave will change first.  Slowly the color will move further into the leaf leaving the midrib to be the last green segment. This is due to how the plant receives its nutrients from the roots and other parts of the tree.  

Temperature, light, and water supply are the primary factors that influence the pigment of the leaves resulting in no two autumns ever being alike. Red colors often develop on exposed leaves due to the bright light they receive. A similar result occurs when there is a mild drought. Color intensity will decrease if there are several rainy days near the peak of coloration. The biggest impact that weather has is delaying the onset of the fall colors due to a late summer drought. Therefore, it is generally said that the best fall foliage occurs when there is a dry, late summer with rain in early fall or when there is heavy rain and bright sunshine with the gradual drop in temperatures.  

The bad part about the leaves changing colors is that the color never lasts as long as we wish it would. Instead the leaves eventually fall to the ground resulting in a yard that is covered in crumbly red, yellow, and orange decaying leaves. This pesky problem can be a good item to compost and can provide a chance to have some fun with the kids.  

Fallen leaves can be a good item to compost since they have enough microorganisms on them to start the composting process fairly easily. If you add grass clippings to the compost, it will provide the added nitrogen needed to speed up the process. The resulting compost is great to use as a soil conditioner. Adequate moisture for composting leaves is about 40-60% moisture. Therefore, it is a good idea to wet the leaves in the compost. If too much moisture is provided, then the compost will begin to smell. To help with the composting process, it is best to turn the pile from time to time to allow air to enter it and the decomposing to occur. Similarly, the pile may need turned to maintain the proper temperature in the compost.  

Visit our homepage at www.extension.purdue.edu/putnam or you can contact the local Purdue Extension Office by calling 765.653.8411 for more information regarding this week’s column topic or to RSVP for upcoming events. It is always best to call first to assure items are ready when you arrive and to RSVP for programs. While many publications are free, some do have a fee. Purdue University is an equal access/equal opportunity institution. All times listed are Eastern Time.

Upcoming Events:

October 20-26 – State IEHA Week

November 1-2 – Extension Homemakers Craft Fair – Fairgrounds 

November 3 – Putnam 4-H Volunteer Recognition & Member Awards Program, 2pm,
                        Fairgrounds

November 3 – College GOAL Sunday, FAFSA Help, Ivy Tech Greencastle, 2-4 pm

November 4 – Putnam County Remove Invasive Plants Meeting, SWCD Office, 12 Noon

November 14 – Knives and Garnishes 101, Area 30 Career Center, 12-pm, $5

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