How past land use affects the current landscape

Do you see how the ground level is higher on the left-hand side of this photo? To the right of the stone wall, the ground distinctly drops by a foot or more.

That wall is more than 200 years old. It marks the border between what was once a plowed field (on the left) and grazing pasture (on the right). Today, this site is woodland—part of the Harvard Forest, the most-studied forest in the world. But for generations, this land was farmed by Jonathan Sanderson and his descendants. And, even two centuries later, you can still see the way different uses of the land changed the land.

For instance, the ground level is higher on the left because plowed fields erode more easily. This site is on a slight slope. Water runs downhill, toward the right hand corner of the photo. As it did that, it carried bits of plowed field along with it—sediment that washed up against the stone wall and stayed there. Over many years, the effect changed the level of the land.

This isn't necessarily a catastrophic thing. But it is change. I spent last weekend in the Harvard Forest, participating in science in a hands-on way as part of the Marine Biological Laboratory's science journalism fellowship. One of the things I learned during my stint in the forest: The past ain't past. History is recorded in geology and ecology as surely as it's recorded in books. Very cool stuff!



  1. Nice to see a forest ecology post, Maggie. I study the conifer forests of the PNW and once you know what to look for, the evidence of land use, be it controlled burning by Native Americans, wild fires of various intensities, logging, or recreational use, the history of the land is there to be read. Very cool stuff indeed!

  2. Another fun one:  When you’re walking in a relatively young forest, you’ll sometimes see a row of much bigger trees stretching off into the woods.  Those big trees were on the fence line of an old pasture or agricultural field.   The rest of the field became the forest you’re walking through, but the fence line had a head start.  If you look at fields still in use, you can see the trees growing at boundary lines.  Much of the eastern US has more forest now than 100 years ago, so this kind of landscape is fairly common in the eastern US.

  3. If you have a chance, look up and visit some of the postage-stamp-sized plots of virgin New England forest.  You’ll notice a completely different character to the function and feel of the woods.  For one, the taller trees separate the canopy from the understory more, perhaps by 2x, and also therefore the wildlife patterns are different.  So the birds we get used to, such as thrushes and chickadees, are much further away.  You can get a better sense of the timing and distance of how things used to be.  It’s fascinating to see these old areas.  And to appreciate the adaptability of life in the midst of big change, as well as to keep an eye toward preservation.

    1. I have spent a lot of time in Algonquin Provincial Park in Ontario, on canoe trips and the like. As in, in all I’ve spent over a year of my life within the park.

      Almost the entire area was logged in the late 1800’s and early 1900’s. There’s lots of neat stuff left over from those days, like pieces of machinery, all throughout the park. But in the mean time the forest has grown back with a vengeance, and most people don’t realize it was ever logged at all.

      But – there are a few patches of forest that survived logging. For someone that’s used to the woods there, walking into one of those patches is immediately striking. The forest is much more mature, and almost all of the plants are different. The giant white pines (which were the prize tree of the logging days and now gone from the park except in these few patches of virgin forest) are immense, which decreases the size and density of the other plant life (it’s just like you describe in New England).

  4. In the prairie land, the equivalent to the rock wall is terraces. It’s kid of ironic… the prairie grasses could handle the erosion on a gentle slope, but cultivated ground couldn’t. But since those terraces collect water and divert it into streams or gullies, they are causing erosion problems.

    1. Besides holding topsoil with their awesome perennial roots that can go 3 meters, prairie grasses are also top tier carbon sinks. 

      Too bad if people aren’t sacrificing some cultivation to grasses on slopes, they are super beneficial

  5. Love it. Looking at a glance it could be that solidly built stone walls around plowed fields, especially if sloped, were good for the ecology in this instance. 

    Besides being something to do with all the damn rocks you get out of a field. I grumble at you, Canadian Shield, for muh aching back and arms. And that’s just from our little 25m x 15m vegetable garden. 

    I probably got 1000 kilos just from making that patch workable, now stacked in impromptu cairns around outside the garden fence, thinking I might shore up the lane here and there.

    edit – yeah, I know I didn’t get them all, there are always more.

    1. A well built and dressed dry stone wall was considered a significant part of a life’s work back then, added to every year as new rocks came up with the frost and plow. The piled walls like the one in the photo were somewhat less time-consuming, but a job of work nonetheless.

    2. In Algonquin Park there are a few places that were cleared of rocks for farms in the logging days. It’s hard to imagine the backbreaking process of clearing all the rocks by hand. It’s surreal to walk through one of those areas now because the ground is soft and flat, and there are immense piles of rocks at regular intervals. You really appreciate how rocky Canadian Shield ground normally is once you see a spot that’s been cleared.

  6. Back when, a field was plowed across the hill, as opposed to up and down. The moldboard of the plow turned the soil over to one side or the other, and the easiest way was to turn the furrow to the downslope side. The animal and farmer would catch their breath on the walk back, and repeat. Each year, the equivalent of one furrow’s  soil would wind up at the wall at the bottom of the field. Over time, you see the result. Certainly erosion played a part as well.

  7. For anyone interested in this sort of thing, I cannot recommend enough the book “Changes in the Land” by William Cronon.  It examines a wide range of data (such as ancient and recent tree pollen deposits and analysis of primary-source historical records) to understand how human habitation shaped the forests of the Northeast U.S. with a particular focus on how market economy forces drove the behaviors of Native and European americans and reshaped the landscape.  I’m sure our understanding of these processes has evolved since Cronon wrote this book, but it’s very accesible and a great overview.

  8. In addition to human activity, beaver activity has figured prominently in the evolution of the landscape. Beaver dams reroute water flow, creating “artificial” ponds and lakes, which later on fill up with silt. Here in the Pacific Northwest you can find complex terraced landscapes all the result of beavers.

  9. The old timers here might remember old school hardware hacker/diy guru Don Lancaster. These days, one of his interests is archaeology around his stomping grounds in southeast Arizona. And he’s been coming up with some interesting information regarding prehistoric land use. He posts about it once a week or so here:

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