The Trees in Shenandoah National Park by Seth Abbott
The sight of the beautiful forested hillsides in the park
at first brings to mind Longfellow’s introductory lines in the poem Evangeline:
“This is the forest primeval,The murmuring pines and the hemlocks,Bearded with moss, and in garments green, indistinct in the twilight,Stand like Druids of eld, with voices sad and prophetic”
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| View from Dickey Ridge Outlook in Shenandoah National Park |
About 1904, the pathogenic sac fungus, Cryphonectria
parasitica, the cause of “chestnut blight, was accidentally introduced into the eastern United States through
imported Asian chestnut lumber or trees. This caused a mass extinction of the
majestic American chestnut tree, which grew between 50-200 feet in height with trunks
up to 14 feet around and were the main lumber used to construct American houses
east of the Mississippi for three centuries. Whereas the European and the Asian
chestnut tree had some resistance to the chestnut blight, the larger American
chestnut tree had none. By 1940, the American chestnut tree had been virtually
wiped out and the chestnut blight had deforested almost a quarter of Shenandoah
National Park.
Another large tree, the Eastern hemlock, had also been
widespread in the southern Appalachians up until the 20th century. Timber
harvesting had greatly reduced its numbers throughout the century, and in 1988,
an Asian insect (the wooly agelid) arrived to nearly wipe out the Eastern
hemlock population.
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| The Massanutten! This is as far as we got before the fog banks made us turn back. |
With few hemlocks and chestnut trees present today, the
view of the park forests is now dominated by red oak, maple, birch, and ash. As
seen in the photos, the mountains are beautifully forested, but one is left
with a lingering sadness at the loss of what had been the most majestic of
the Appalachian trees. Today, we do not see the forest primeval at the park.
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| View from Signal Knob Outlook in Shenandoah National Park |
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| Heading back down and away from the fog. |
For further information on Shenandoah National Park, the trees of the region and the Appalachian Trail (Virginia has more miles of the trail in it than any other state it goes through), we recommend the following books (all available in our store or by clicking on the picture below):
Once you're done being saddened by the loss of trees and you are worn out from hiking, go get yourself an amazing burger and fries at Spelunker's in Front Royal. Greasy awesomeness. The name Spelunker's comes from the nearby Luray Caverns and Skyline Caverns where you can go, that's right, spelunking. Check out the Fried Eggs at Luray Caverns.
Very informative and great pictures. I like the fog! Did the forest service do anything to try to stop the blight/beetle, or did they recognize the problem too late?
ReplyDeleteExcellent question! And it led me to do a little more research, which is how I found that there is a foundation at Virginia Tech called the American Chestnut Cooperators' Foundation or ACCF (http://ipm.ppws.vt.edu/griffin/accf.html) which is trying to restore American Chestnuts (not the hybrid, blight-resistant kind that American Chestnut Foundation or ACF is working with) to the forests of Virginia. It also looks like the National Park guide did not have it completely correct - the American Chestnut population was devastated and all of those huge trees are gone, but some trees did survive, at the "heart of the natural range" (http://www.accf-online.org/Blight/Control/integrat.html). I wasn't immediately able to figure out what the forestry service did or didn't do when they found out about the blight, but several sites said that they believe "panic logging" occurred when people found out what was happening and that may have been a major contribution to this particular environmental disaster. It looks like it was a nasty combination of man and nature, but these foundations are doing a lot of research to help the recovery.
DeleteAnd from Seth himself: "Good question. The chestnut blight was caused by an Asian fungus, which destroyed the cambium of the American trees. In the early 1900s, very little was known about this particular fungus. Unfortunately, the fungus reproduces by forming many spores which are then blown by the wind to any chestnut trees in the vicinity of the infected tree, spreading the fungus throughout the forest. Since the American chestnut tree had no resistance to the Asian fungus, and since the trees were concentrated in the southern Appalachians, they were annihilated (in that area). That the American tree had no resistance suggests that the American trees might never have been exposed to this fungus, prior to 1900. Asian trees had some resistance, which mght be because they had been exposed to it, and over time had developed resistance, eons ago. Later research on breeding a resistant American Chestnut tree began by isolating a tree (presumably a mutant) with some resistance from a stand of surviving American chestnut trees in another area, which had been far from the infected eastern trees and thus not within the wind-spread radius of the Asian fungus spores. Unfortunately, the trees that were then produced, in addition to having some resistance to the fungus, failed to grow to the size of the American Chestnut trees that had been annihilated. Genetic engineering would seem to be the best remedy to the problem of regenerating the massive American Chestnut trees,,but this will require identifying the mutation to the gene(s) which can confer resistance to the Asian fungus and also identifying the genes which govern the tree growth. The latter may be a whole complex of genes. None of this is well understood at the moment. Most government funding of genomics research has been devoted to understanding the human genome and the genomes of the microorganisms which cause major diseases in humans, not leaving much funding for the forest service research needs. Since the current administration appears to like trees more than people, there is hope." Yup. Just liking discussing politics and biology at the dinner table when I was a kid. Oh, nostalgia. Thanks, Dad.
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