suzettesoule
Fuzzy Killers
For spring break I went back home to the mountains. I was young when my ecology-loving mom first told me about how hemlock trees would soon be driven to near extinction just like the American chestnut trees that used to dominate the forests in our area. I already feel like I have seen a dramatic change in the local population of hemlocks since then. The Carolina hemlock (Tsuga caroliniana) pictured here was only about 2 feet tall and already infected by the hemlock woolly adelgid (Adelges tsugae), a fuzzy, white, aphid-like parasite. It was first reported in the Eastern US in 1951 after being introduced in 1924 from Japan, making it an invasive species recognized by the U.S. forest service. The woolly adelgid feeds on sap, and since it has no local predators, large numbers can prevent growth and completely desiccate a tree. Hemlock are a characteristic part of the understory in WNC forests, providing habitat and food for many species. Most of the treatments for woolly adelgid infestations involve chemical insecticides, which can't feasibly cover the entire population. Other more effective methods would be to introduce a natural predator of the woolly adelgid, like the beetle Laricobius nigrinus, which is native to western North America. While introducing new species can also produce an unpredictable effect, it may be the most hopeful way to save the hemlocks.
Sources:
www.na.fs.fed.us/fhp/hwa/pubs/95_proceedings/Quimby.pdf
Fuzzy Killers
For spring break I went back home to the mountains. I was young when my ecology-loving mom first told me about how hemlock trees would soon be driven to near extinction just like the American chestnut trees that used to dominate the forests in our area. I already feel like I have seen a dramatic change in the local population of hemlocks since then. The Carolina hemlock (Tsuga caroliniana) pictured here was only about 2 feet tall and already infected by the hemlock woolly adelgid (Adelges tsugae), a fuzzy, white, aphid-like parasite. It was first reported in the Eastern US in 1951 after being introduced in 1924 from Japan, making it an invasive species recognized by the U.S. forest service. The woolly adelgid feeds on sap, and since it has no local predators, large numbers can prevent growth and completely desiccate a tree. Hemlock are a characteristic part of the understory in WNC forests, providing habitat and food for many species. Most of the treatments for woolly adelgid infestations involve chemical insecticides, which can't feasibly cover the entire population. Other more effective methods would be to introduce a natural predator of the woolly adelgid, like the beetle Laricobius nigrinus, which is native to western North America. While introducing new species can also produce an unpredictable effect, it may be the most hopeful way to save the hemlocks.
Sources:
www.na.fs.fed.us/fhp/hwa/pubs/95_proceedings/Quimby.pdf