Looking for a opinion to a question about invasive and woody succession I've always had.

Asked November 15, 2019, 1:38 PM EST

Thank you for providing this "ask the experts forum". It's so cool!. I have a 2 part question. I will try to keep it clear and brief. When my parents were kids and even grandparents were young, they, along with all the neighborhood kids, played continually on a old sandy sandhill, in the middle of the woods. It sits on a ledge of sorts. As a child of the1980's my generation, again played every day, continually on this sandhill. I'm all grown up now and decided to take a look at the hill, the other day. I was astounded at what I found. To even get to it, was a task. When I did, wow, full of small trees, woody succession all over it. You could barely see the sand on top of the hill. I'm familiar with all this, but my question is this. After thousands and thousands of years of loose sand and few trees on top the sand hill and ledge, as well as other places I know of, why in just this small amount of geological time, only 20 years of my generations childhood, did it succeeded over to this degree?. Is the answer what I think it will be.. Children no longer playing outside.
I know about off road vehicles keeping the sand free of encroachment, as well as once walked paths, no longer walked. But to this degree in just 15 to 20 years of missing foot traffic?. I fear my answer is correct. Why wouldn't this of happened 1000 years ago or even 500?. My other part of the question is about the glaciers as they left. When did the waters of the Predecessor lakes to Lake Erie, turn from open waters, to forested waters and swamps, like we still see today. Could you give me a rough Idea on this process?. Thank you Guys so Much!!

Monroe County Michigan

1 Response

Hi, there,
Your questions are interesting! I'll do my best to touch upon some theories here; feel free to call me to discuss further (I'm out tomorrow, 11/21, back in the office 11/22).
The succession on the sand hill could have occurred due to changing demographic of the neighborhood. Are there houses nearby? Do the people have children to play on the hill? Children still play outside, and sometimes have to be shown or 'discover' areas of play. I've introduced children to areas on state land through field trips; a few of the students reported returning to play there.
The maturity of the surrounding trees also came to mind. Are the trees now mature and therefore, producing additional seed that caused the succession?
The geologic history of our area is a fun topic to discuss. When the glaciers receded they melted into water that over-filled what are now the great lakes. The lake basins were carved out by the glaciers, and those basins were over-filled to create the 'black swamp' that is now fertile farmland in northern Ohio and Indiana. As the waters evaporated, the water receded into the basins we now know as the great lakes. Conversion of the land to agriculture with the installation of tiles and ditches further helped drain those areas. Today, we have forests in the areas that traditionally flood, as they are not suitable for farming, even with tile drainage.
Here is a link to the "Geologic History of Michigan" that might answer your questions in more depth.
https://www.michigan.gov/documents/deq/GIMDL-GGGHM_302331_7.pdf
That's just a bit of what I know. If you have further questions, let's talk! Feel free to call me if you'd like to discuss.
Thank you!
Julie