Backyard Biodiversity November 2020 Fall Foliage

Sugar Maple (Acer saccharum) 

For most in the Midwest and Northeast fall is a time when the leaves change colors. The bright reds, oranges, burgundies and yellows are from pigments in the leaves that are actually there all year long, we just do not see them because during the rest of the year the green pigment, chlorophyll, is most abundant. This is the pigment that allows the trees to capture sunlight and produce its own food (photosynthesis). But when fall and winter come around, the chlorophyll breaks down as the nutrients used for plant growth move from the leaves into the stems and roots for storage. With the chlorophyll gone, we now see the other pigments in the leaves before they fall to the ground.
 

​Maple trees have some of the showiest fall foliage. Maple trees are native to North America, Europe and Asia, with the most number of species in Asia. Here I have what I believe to be a sugar maple (Acer saccharum). Sugar maples are native to eastern North America, and are best known for they sugary sap that is used to make maple syrup.  As can be seen on this photo sugar maple leaves (like most other maples) have 5 lobes in a palmate pattern, that is the veins and leaf lobes extend from the base of the leaf. 
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Maples are really pretty in the fall, especially with a bright blue sky behind them. Maples are also one of the earliest flowering trees, at least in my yard. Usually in March, small, tiny flowers appear before any leaves do. This provides a great source of nectar for early spring insects. The fruits and seeds of the maple are the 2 seeded, papery-winged, whirlybirds or helicopters seen whirling from the trees in spring time.

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The next tree is an oak tree. There are around 400 to 500 species of living oaks in the genus Quercus , and they are native to the northern hemisphere. The highest species diversity of oaks can be found in North America, with Asia having the second highest number of oak species. I do not know a lot about trees or oaks. I always assumed that oaks generally do not display a lot of fall color. From my experience oak leaves generally turn brown and either fall off the tree or remain on the tree over winter.  When I saw this oak with is beautiful red/ burgundy colored leaves, I had to find out what it was. I assumed it was a red oak tree, because of the coloration….but was I wrong! 
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This oak species has leaves with rounded lobes, meaning it belongs to the white oak group.

​There are about 60 species of oaks in the United States. These can be divided into 2 groups, the white oaks and the red oaks. White oaks (such as the white oak, burr oak, post oak and chinquapin oak) generally have rounded lobes on their leaves and red oaks (such as the red oak, black oak, willow oak, and pin oak) have pointy-end tipped lobes on their leaves. So, from this picture I can guess that this tree belongs to the white oak group based on the rounded lobes of its leaves. There are other differences between the groups, for instance the white oak group's  fruit (acorns) mature on the tree in one season, whereas those of the red oak group take up to two seasons before they mature. Unfortunately, I am unable to identify this tree species any further, I will have to go back and visit in spring time to take a closer look at the leaves and stems. The acorns of the oaks are really important source of food for wildlife, and like the leaves come in various forms.

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Credit: University of Minnesota Extension

Credit: Trees: A Golden Nature Guide
(Illustrators: Dorothea and Sy Barlowe)

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While I was doing some research I came across this similar blog. According to the Back Yard Biology Blog team, oaks can be pretty colorful in the fall, check out their post and pictures! Apparently I will have to keep a keener eye out next fall on the oaks!
(https://bybio.wordpress.com/2011/10/28/glorious-oaks/)

And Leeloo says don't forget to enjoy the fall leaves, whether they are still on the trees or on the ground!