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Archive for May, 2014

 

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I have been reading a book by professor Tom Wessels of Antioch University, entitled Forest Forensics: A Field Guide To Reading The Forested Landscape. Within the book, Professor Wessels goes into 3 common types of disturbance, and how to detect evidence of them in the northeastern landscape. The book is a field guide written as a dichotomous key, to help users pick between agricultural impacts, old growth impacts such as wind, ice and fire, and human impacts such as logging. He argues that every action that takes place in a forest is written into the landscape, and if we learn to read that language, we can come to readily see that history. “The new language has nouns, verbs and adjectives just as a written language does,” he writes. “But its words are things such as small stones in a wall, a hollowed-out stump, or a basal scar on a tree trunk.”  These things, in their place, are all telling of the significant activity the forest has experienced.

 

Using his guide, I decided to survey the woodlot behind my house. The wood lot abuts a field that, in my lifetime, has been used to grow corn… Given the history of the Lehigh Valley, it is likely that it has always (since the time of white settlement), been in production for either corn or wheat, or some other grain. The wood lot, however, does not show signs of agriculture, such as stones brought to the surface by the freezing and thawing cycles, and the lack of perennial root systems. Furthermore, it shows the signs of what Wessels calls pillows… “When live trees are toppled by wind or by snow-or ice- loading, their roots rip out of the ground, excavating a pit or cradle. As the tipped-up roots decay they drop the earth they excavated, creating a mound or pillow adjacent to the cradle.” Wessels suggests this is the first piece of evidence we should look for, as it is telling of  an agricultural past. In my wood lot, the pillows are gently rolling and not overly defined. This, Wessels suggests is a sign of trampling by animals (if it had once been a pasture), but it could also be from human activity. Nevertheless, I cannot find significant evidence of agricultural (there are no stone walls, though I remember there used to be a wire fence) or commercial logging impacts (none of the trees have opposing basal scarring, evident of machinery and there are only a few, recent, small diameter stumps with flat, cut tops), and the trees which I aged using his approximation method, are of mixed ages, with the oldest ranging about 150 years old. This evidence taken together, would suggest a mature, but not old growth forest. Likely it was disturbed by light personal use timbering of dead and down wood, maybe an occasional standing tree dropped, but never clear cut. Of the tress oaks and ashes of 2 feet in diameter dominate.

 

There is one tree, however, which I found broke with the rest… A triple Chestnut Oak, with all three trunks about two and a half feet in diameter. Taken together, and taking into account that trees with multiple trunks take longer to grow, I would estimate the tree to be 300-400 years old. The tree shows none of the signs of being a pasture tree, as it has no outward growth on the lower section of the tree. It grew up straight and tall, right to the canopy. It is now standing dead.

 

Using the method Wessels details, I was able to estimate that there was a disturbance  that caused the tree to grow in three sections, when the tree was about 125 years old. There were no signs of basal scarring (neither on that tree or any near by), which would suggest timbering in the area, or a fire. There was no clear evidence of timbering in the rest of the stand, besides what has been done recently for campfires, by local teenagers. The tree presents somewhat of a mystery. Something, it seems, caused the tree to  break off, and to separated into three trunks. It is certainly possible that the tree was timbered, as part of the small scale timbering that likely occurred in the wood lot. If a tree is cut at the stump, there is a possibility for it grow new trunks. Multitrunk trees “are trees and shrubs that have more than one stem growing from a single root mass. These trees have a fused base area that consist of multiple piths at ground level. These generally form when the original stem of the tree was damaged, broken, or browsed by animals, damaged  from falling (natural or man-caused).  This results in a new stem sprouting from the root mass.  In general these stems are all of similar age and size, but will often reduce to developing one, or a few dominant stems” (http://www.nativetreesociety.org/multi/index_multi.htm). It is possible, as it is at the edge of the forest, that severe weather took the initial trunk out, causing the tree to separate into three… But there is no evidence in the rest of the stand to confirm this. What seems more likely is that the tree was timbered at one point, but has recovered threefold, only to die at the upward limit of that species.

 

In any case, the mystery is part of the enjoyment, and I feel Wessels guide has given me a greater perspective on the land in my area. I am hoping to further use the book in my boundary work at the Appalachian Trail Conservancy, when attempting to age timbering and other tree cutting and resource disturbing encroachments. I feel Wessels guide is a must have for all those who wish to mix ecology and history, and especially those wishing to forge a better understanding of land use. He promotes and understanding of how truly intertwined we are with the lives of our forests. We can do nothing that does not show itself in the land, and how can the forest but help to leave its mark on us.

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