It seems that I have just planted my spring crop of peas and now its fall? I remember old men telling me how fast time goes by. Of course I was in my late teens and early twenties; I knew it all and that was how old men talked. Well I now know precious little and the people I thought were old men were younger then than I am now. I am not really sure what has been happened to me but I do have a handle on the color of the trees.
During the growing season most leaves are made green by a chemical called chlorophyll. Plants use this chlorophyll in photosynthesis which leads to the production of glucose then they use the glucose for energy. Of course it is not quite that simple (a lot more goes on). Plants produce oxygen, they filter out toxic material in the air and it all works well until the season changes. Chlorophyll is produced with the help of the sun and warmer temperatures and as the days become shorter and the temperature --especially night temperature-- begins to drop, the production of chlorophyll slows down.
So where are the tree’s new colors coming from? I used to tell my brother that small woodland critters did it and they were going to get to him too. I always wanted to “put the water colors to him” while he slept, but figured the only thing that would remain red was my backside when Dad got home. Somehow Mom always forgot to tell him any of my misadventures when he got home but I knew the threat was real. So, anyway, the yellow and oranges are there in the leaves all season long but they remain covered up until the green chlorophyll starts to break down. Probably our favorite yellow oranges are from the Sugar Maple, Acer saccharum that change yellows to burnt oranges with some red. Yellow and oranges are also found in several ashes Fraxinus americana and pennsylvamica that are found from Nova Scotia to Texas, Paper Birch Betula papyrifera found although North America.
The red leaves, well they take a little more chemistry for their big show. Remember when I said that chlorophyll help to produce glucose; well it’s that leftover glucose that turns red in the leaves at the end of the growing season. When we are seeing reds we are seeing plants like Red Maple Acer rubrum. Red maples have many cultivars that have very strong red fall color like Red Sunset and Autumn Blaze. American Hornbeam Carpinus caroliniana will show off several colors yellow, orange, red and reddish purple according to Dr. Michael Dirr. Pin Oak Quercus palustris is maybe the best oak for fall color as it turns bronze to red.
There are hundreds even thousands of other shrubs and trees that grace our colorful fall landscape with these colors and with many variations. I think it’s this color, the fresh air and fall smells that makes fall my favorite time of year. Now if I hurry I’ll get my peas in by April 15th!
Terry Skillin
Skillin's Greenhouses
October 3, 2010
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