Dunes Succession (Birthplace of Ecology)

OK, I admit I'm stretching this series a little, but I love the area so much and really want to share it.  I was still playing around with photographing snow fences at the state park when I took this photo.  I'm posting it though because it's a good example of a process called dunes succession that I mentioned in my post yesterday.  Succession is sort of like evolution from non-organic to organic matter, and dunes succession begins with marram grass which can grow in the sand just out of reach of the largest waves.  The grass has an extensive underground rhizome system and when it decomposes, it starts to change the sand by adding humus.  When the sand is sufficiently changed, it paves the way for new plants like cottonwood, Jack pine, ash, black oak etc. creating a cooler canopy, and the process continues.  The most mature dunes forest is beech-maple, which is what I started this series with in "Long Road Home".  The Great Lakes which were formed by melting glaciers have shifted over the years, and those forests which are miles from the beach now, were once beach themselves.  Anyway, it's a cool process, and we all learned about it in school here.  The once controversial idea was postulated by a University of Chicago professor (Cowles) in the early 1900's.  It became a famous idea, although not as famous as Darwin, but it did give this area claim to the title Birthplace of Ecology.