By Ian Burrow (email@example.com)
Fig 1. Eroding Mill Dam
If you have taken a hike on any one of the preserved areas on Sourland Mountain, chances are that you have noticed a tumbled stone wall, an earthen bank by a stream, A huge tree standing out among its smaller neighbors, a rusting piece of farm machinery, rocks with holes drilled into them, the rotting trunks of cedar trees, the bed of an abandoned road, or perhaps even the foundations of a long-forgotten building. For me, each of these features tells a piece of the story of the Mountain, and how people have interacted with it over hundreds and even thousands of years.
Figure 2. Old road trace and wall
I would like to share with you what I am learning about this history, and to help and encourage you to discover it for yourself.
People go the Sourland woods for many excellent reasons. Some watch and record wild birds, others search for the native plants, lichens and fungi unique to this place. On cold rainy nights in early spring, hardy souls help amphibians cross the roads to vernal pools. Some folks are on a mission to seek out and destroy invasive plants. Many others are there for the peace and beauty of the trails, to enjoy the open air, to be strengthened and replenished by nature, and perhaps to seek out the mysterious rocky outcrops and giant boulders that litter the landscape.
I’m an archaeologist. That means I’m interested in studying and understanding the physical evidence that people from the past have left behind. This evidence can take many forms. Most people immediately think of Indian arrowheads and other old and unusual artifacts when archaeology is mentioned (some people also think of dinosaurs, but those beasties are for the paleontologists). Artifacts are an important part of the archaeological record, of course, but for Sourland Mountain we are talking mostly about a rather different kind of archaeology.
It goes by various names. In the UK, where I come from, it’s called “Landscape Archaeology”. That term has a slightly different meaning here in the United States, where it has come to be chiefly associated with the study of the formal landscapes and gardens of the powerful. So I tend to call what I do “Cultural Landscape History”. Let me explain what I mean.
It is easy to imagine that when we are out in the woods, or in wild or wilderness areas, that we are in unspoiled nature. We can readily think that we are seeing places where human hands (and feet) have not changed the environment. There are still places like this in the World, but not as many as you might think. Very few of them are in Eastern North America, hardly any are in New Jersey, and none at all are on Sourland Mountain. Almost everything that you see in the Sourland Landscape is in some way the result of what people have been doing here in the past. So this is what is meant by a “cultural landscape”: land that has been altered from its original, pristine appearance by the activities of human beings. Some of the alterations can be very obvious, others more subtle. Cultural landscape historians try to peel back the layers of this history to see how things have changed through time.
So, let’s look at some of the features in the Sourland Landscape that will give up some of their secrets if we ask them the right questions. We’ll start with
They are hard to miss on the Mountain! One thing that you will notice is that in many places the trees are all much the same height and size, with the tree trunks rising straight up for many feet before the branches open out. The tree trunks are often slender: 18 inches in diameter or less.
Fig 3. Young deciduous forest
If we could talk to these trees they would say something like this: “We all started growing at the same time a few decades ago. The trees that were here before us were all cut down and cleared away at one go, leaving open ground for us to colonize together.”
That’s all very interesting, we may say, but exactly when did you all start growing? In order to learn this from the trees themselves we need to do two things.
The first is to learn how to identify tree species from their bark, leaves, and overall appearance. There are many Sourland-lovers who are much more knowledgeable about this than me, so it’s a good idea to have them on hand as teachers. There are also lots of good reference books you can take out with you. One of my favorites is Bark: A Field Guide to Trees of the Northeast by Michael Wojtech. I like this because I tend to be out in the woods in fall, winter and early spring, when the leaves are unhelpfully lying on the ground instead of being attached to their trees.
Once you have identified your tree species, you then do a little measuring, using the measuring tape that you have remembered to bring with you. Otherwise you will have to go back to the car to get it.
This is what you do:
- Measure the circumference (distance around) of the tree at a height of 4’ 6” above the ground.
- Using your geometry and math skills, work out the diameter of the tree. Remember pi? Pi is your friend. Divide the circumference of the tree (in inches) by the magical value of Pi, which is 3.14. Make a note of the result.
- Now you consult a Tree Growth Factor Chart like this one:
Fig 4. Tree-Growth Factor chart
Find your tree species on the chart and make a note of the “growth factor” number
- Multiply the diameter of the tree by its growth factor. The result is the approximate age of the tree in years. Magic! Impress your friends and family!
You may rightly ask where these “growth factors” come from. The International Society of Arboriculture is where. They know what they are doing as far as trees are concerned, so we may rely on them.
Every so often you will see a tree quite different from the slender ones we have just been talking about:
Fig 5. Wolf Tree
This tree is not only big, with a thick trunk, it also has many branches spreading out widely in all directions, starting quite close to the ground. It may not be much taller than the trees that surround it, but it is much more massive. Landscape historians call this a Wolf Tree.
Let’s ask it a couple of questions: “Hello, wolf tree, why are you so different from most of the other trees around here, and why do they call you ‘wolf’?”
“These other trees are much younger than me. Measure my trunk and you’ll see. For a long time I was the only tree around here. I was surrounded by pastures and meadows where cows were grazing. The cows sheltered from the summer heat under my spreading branches, and could also browse the leaves from the lowest branches. Farmers cleared the other trees to make the pastures and meadows, but left me as a “lone wolf” to give shade to their livestock. After a while the cows went away, and these other trees grew up around me on the abandoned fields.”
So these lovely trees take us back to the time, a hundred years ago and more, when much of Sourland Mountain was open grassy fields.
Eastern Red Cedars
Juniperus virginiana, to give it its scientific name, is a coniferous (evergreen) tree that eventually grows to a height of 30 to 40 feet, often in groups or stands. On Sourland Mountain you will see them in four main settings:
- As fairly small trees scattered across grassy pasture fields. We see them here because they are often the very first tree species to colonize pastureland, once cows have ceased to graze it, or it is no longer mowed for hay. Eastern red cedars love these old pastures.
Fig 6. Easter Red Cedars
- As a dense, dark, almost gloomy, woodland. This is what happens after 20-30 years of the growth of these trees. They have successfully colonized the old pasture and are, for now, the dominant species.
- As sickly-looking trees surrounded and overshadowed by bigger deciduous trees. The reign of the cedars is coming to an end as other trees overtop them and cut off their sunlight. Eventually the cedars die.
- As rich red-brown crumbly tree-trunks lying on the woodland floor. After they die the cedars gradually fall and decay as the other trees continue to grow.
Next time: stone walls!