Standing Still
Sarah Sussman | December 2017
Recovering our breath from hiking back to the Clingman’s Dome parking area from Andrews Bald, my family and I decided to be tourists after our hike and climb the half mile up to the Clingmans Dome observation tower, the highest point in Tennessee. With strong binoculars, one can see the Dome in the distance from our home in Bryson City, NC. The view from the top is the reason visitors of the Great Smoky Mountains National Park flock to the observation tower - miles and miles of protected land lies beneath one's gaze. The curvature of the Appalachians is grand in scale and without a doubt, beautiful. However, there was something slightly melancholy about the view and after reading some ecological information posted at the top of the tower, I discovered that the source of my emotions were the dying trees amongst the evergreen ones.
The bleached, bare, tall, and dead Eastern hemlocks are scattered sporadically when you look out from Clingmans Dome. The view is the same all along the Appalachians up into Nova Scotia and as far wide as Illinois and Minnesota. The International Union for Conservation of Nature (IUCN) red list for global status lists Eastern hemlocks as “near threatened”. The reason for the Eastern hemlock’s plight? An invasive species called the hemlock woolly adelgid.
The adelgid is from Asia and although the origins of its introduction into North America is still unknown, it is thought to have been brought over accidently from Japan in the 1920s. The adelgid first infects the base of a hemlock needle and from there it spreads. At the base of the needle the woolly adelgid inserts its mouth into the tree tissues and gains access to the trees food storage cells. In response, the hemlock repairs the hole created by the adelgid by covering it up, almost how the human body creates scabs. However, this wall created by the tree is impermeable to nutrients, and as a consequence, the pine needles and eventually the whole limb are devoid of any nutrition and eventually will die off within five to fourteen years. An infected Eastern hemlock is easily identified, as it has a white mass that looks like cotton, resting on the edge of its pine needles.
This image has haunted me along with the greater realization that one day Eastern hemlocks may not be around. Every time I go hiking in the Appalachians, I can easily see the damaged trees from the summit. Eastern hemlocks are a vital ecosystem contributor. They provide a cool microclimate by casting shade along streams for aquatic life adapted to cool waters such as trout (a popular Appalachian dish), salamanders, and other invertebrate.
The loss of the Eastern hemlock will also contribute to the loss of numerous species and cause disruption in ecosystems functions. During the summer, Eastern hemlocks provide 50% of the total water transpired by deciduous trees! Think of how this will affect the water cycle once the species is severely endangered or extinct. On top of that, The U.S. Forest Service estimates that nearly 800 species of insects rely on the Eastern hemlock for day to day life. As the decline of the Eastern hemlock becomes greater, the decline of these species is inevitable.
Climate change is also contributing to the spread of the Hemlock woolly adelgid. As temperatures rise globally, the range of the woolly adelgid could expand farther north, and cover the entire northeastern United States. Adelgids cannot survive harsh winters; this explains why adelgids are slow to spread north. However, with rapidly warming northeastern winters the adelgid is expected to survive more north than it’s ever been. Adelgids cannot thrive under -5 degrees Celsius, and from 2010-2039, northeastern winter temperatures are expected to rise 1.5-2 degrees warmer—by 2050, 3-4 degrees higher. This would mean a greater number of hemlocks would die as a result of the adelgid and alterations in ecosystem function would look much like the adelgid infestation in the more southern parts of the region. With the brewing threat of climate change, it’s hard to find optimism and solutions to a worldwide temperature phenomena.
Fortunately, there are ways to slow the adelgid and the National Park Service uses three methods, the most popular one being the systemic treatment, where hemlocks or the soil around the tree is injected with an insecticide (of course, this has its unintended consequences as well). Using this method, the Great Smoky Mountains National Park has treated 200,000 Eastern hemlocks. Another method, although not nearly as popular, is the National Park Service unleashing a predatory beetle, non-native to North America, on the hemlock woolly adelgid. As of 2011, 500,000 of the beetles have been unleashed. Because of concerns related to the release of another non-native species you could say this method is still being developed and the results of this tactic are still unclear.
My parents live on the border of the National Park, and last year themselves and their neighbors gave 271 Eastern hemlock trees a second round of systemic treatment against the woolly adelgid, all within our neighborhood. Treatments are spaced seven years apart and were given to already infested hemlocks. There is a 50% chance of full recovery for the hemlocks they have treated. Today, 265 of the 271 are still living, meaning that their treated trees have had more than a 95% success rate so far. My mom told me that being a part of this neighborly effort led her and my dad to treat four hemlocks on their property. She said that being a part of the treatments was rewarding because it showed how much of a difference the treatments were making to the health of the trees and the surrounding ecosystem; she said there were baby hemlocks sprouting up. This is amazing considering it takes twenty to forty years for an eastern hemlock to produce seeds.
The biodiversity crisis is not just hitting animal species that move around like us, it is hitting a species that is standing still -- a species which we often ignore or categorize as commonplace, and it’s all our fault. The best we can do is to keep treating hemlocks and maybe innovate new ways to get rid of the adelgid. Continuing to lower each of our ecological footprints and acting in accordance to international and local climate solutions plays a huge part in combatting climate change, and indirectly the Hemlock woolly adelgid. Hopefully one day there will be no massive loss of dead trees along the ridges and in the valleys of the Appalachians.
Sarah Sussman | December 2017
Recovering our breath from hiking back to the Clingman’s Dome parking area from Andrews Bald, my family and I decided to be tourists after our hike and climb the half mile up to the Clingmans Dome observation tower, the highest point in Tennessee. With strong binoculars, one can see the Dome in the distance from our home in Bryson City, NC. The view from the top is the reason visitors of the Great Smoky Mountains National Park flock to the observation tower - miles and miles of protected land lies beneath one's gaze. The curvature of the Appalachians is grand in scale and without a doubt, beautiful. However, there was something slightly melancholy about the view and after reading some ecological information posted at the top of the tower, I discovered that the source of my emotions were the dying trees amongst the evergreen ones.
The bleached, bare, tall, and dead Eastern hemlocks are scattered sporadically when you look out from Clingmans Dome. The view is the same all along the Appalachians up into Nova Scotia and as far wide as Illinois and Minnesota. The International Union for Conservation of Nature (IUCN) red list for global status lists Eastern hemlocks as “near threatened”. The reason for the Eastern hemlock’s plight? An invasive species called the hemlock woolly adelgid.
The adelgid is from Asia and although the origins of its introduction into North America is still unknown, it is thought to have been brought over accidently from Japan in the 1920s. The adelgid first infects the base of a hemlock needle and from there it spreads. At the base of the needle the woolly adelgid inserts its mouth into the tree tissues and gains access to the trees food storage cells. In response, the hemlock repairs the hole created by the adelgid by covering it up, almost how the human body creates scabs. However, this wall created by the tree is impermeable to nutrients, and as a consequence, the pine needles and eventually the whole limb are devoid of any nutrition and eventually will die off within five to fourteen years. An infected Eastern hemlock is easily identified, as it has a white mass that looks like cotton, resting on the edge of its pine needles.
This image has haunted me along with the greater realization that one day Eastern hemlocks may not be around. Every time I go hiking in the Appalachians, I can easily see the damaged trees from the summit. Eastern hemlocks are a vital ecosystem contributor. They provide a cool microclimate by casting shade along streams for aquatic life adapted to cool waters such as trout (a popular Appalachian dish), salamanders, and other invertebrate.
The loss of the Eastern hemlock will also contribute to the loss of numerous species and cause disruption in ecosystems functions. During the summer, Eastern hemlocks provide 50% of the total water transpired by deciduous trees! Think of how this will affect the water cycle once the species is severely endangered or extinct. On top of that, The U.S. Forest Service estimates that nearly 800 species of insects rely on the Eastern hemlock for day to day life. As the decline of the Eastern hemlock becomes greater, the decline of these species is inevitable.
Climate change is also contributing to the spread of the Hemlock woolly adelgid. As temperatures rise globally, the range of the woolly adelgid could expand farther north, and cover the entire northeastern United States. Adelgids cannot survive harsh winters; this explains why adelgids are slow to spread north. However, with rapidly warming northeastern winters the adelgid is expected to survive more north than it’s ever been. Adelgids cannot thrive under -5 degrees Celsius, and from 2010-2039, northeastern winter temperatures are expected to rise 1.5-2 degrees warmer—by 2050, 3-4 degrees higher. This would mean a greater number of hemlocks would die as a result of the adelgid and alterations in ecosystem function would look much like the adelgid infestation in the more southern parts of the region. With the brewing threat of climate change, it’s hard to find optimism and solutions to a worldwide temperature phenomena.
Fortunately, there are ways to slow the adelgid and the National Park Service uses three methods, the most popular one being the systemic treatment, where hemlocks or the soil around the tree is injected with an insecticide (of course, this has its unintended consequences as well). Using this method, the Great Smoky Mountains National Park has treated 200,000 Eastern hemlocks. Another method, although not nearly as popular, is the National Park Service unleashing a predatory beetle, non-native to North America, on the hemlock woolly adelgid. As of 2011, 500,000 of the beetles have been unleashed. Because of concerns related to the release of another non-native species you could say this method is still being developed and the results of this tactic are still unclear.
My parents live on the border of the National Park, and last year themselves and their neighbors gave 271 Eastern hemlock trees a second round of systemic treatment against the woolly adelgid, all within our neighborhood. Treatments are spaced seven years apart and were given to already infested hemlocks. There is a 50% chance of full recovery for the hemlocks they have treated. Today, 265 of the 271 are still living, meaning that their treated trees have had more than a 95% success rate so far. My mom told me that being a part of this neighborly effort led her and my dad to treat four hemlocks on their property. She said that being a part of the treatments was rewarding because it showed how much of a difference the treatments were making to the health of the trees and the surrounding ecosystem; she said there were baby hemlocks sprouting up. This is amazing considering it takes twenty to forty years for an eastern hemlock to produce seeds.
The biodiversity crisis is not just hitting animal species that move around like us, it is hitting a species that is standing still -- a species which we often ignore or categorize as commonplace, and it’s all our fault. The best we can do is to keep treating hemlocks and maybe innovate new ways to get rid of the adelgid. Continuing to lower each of our ecological footprints and acting in accordance to international and local climate solutions plays a huge part in combatting climate change, and indirectly the Hemlock woolly adelgid. Hopefully one day there will be no massive loss of dead trees along the ridges and in the valleys of the Appalachians.