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By Brian O’Shea, Plateau Daily News
Over 150 hemlocks were treated at The Mountain Retreat & Learning Center last week in a collaborative effort between the Hemlock Restoration Initiative, The Mountain, and Highlands-Cashiers Land Trust.
“Currently, treating hemlocks with insecticide is the most reliable way to protect them from hemlock woolly adelgid,” said HRI Director Margot Wallston. “Without protection, both eastern and Carolina hemlocks decline in health and most eventually die from the invasive, non-native insect. It is important to keep hemlock trees healthy because of the disproportionately large impact they have on the environment around them.”
Group of volunteers treating hemlocks at The Mountain include members of Highlands-Cashiers Land Trust, Hemlock Restoration Initiative, and Team Rubicon.
HCLT Land Conservation Director Andrew Renfro said Eastern Hemlocks are under attack across their range along the east coast from a non-native invasive bug called the hemlock woolly adelgid (HWA). At The Mountain, many hemlocks have already perished from HWA, causing not only ecological damage but also posing safety risks to campers as well as property.
An HRI tech measures the proper dose of chemicals to treat a hemlock of this size. The hemlock being treated is the tree in the far right of the photo.
Several larger deceased trees that had succumbed to HWA have already fallen, damaging the boardwalk around the lake and preventing the use of The Mountain’s ropes course area.
“The majority of their surviving trees were in severe decline and likely would die within the coming years without intervention,” said Renfro. “It’s not hard to see the impacts of HWA in Highlands/Cashiers, just driving on Highway 64, hundreds if not thousands of dead trees can be observed.”
HRI Executive Director Margot Wallston chats with a member of Team Rubicon about the importance of treating hemlocks.
Volunteers from all organizations involved, including volunteers from Team Rubicon who were on-site improving fire mitigation at The Mountain, treated hemlocks with systemic insecticides using a “soil drench” application to the roots of the tree.
Wallston said the treatment with chemicals moves into the whole tree and out to the branches where the hemlock woolly adelgid feeds.
“When the insect feeds on the tree, it ingests the chemical and dies,” said Wallston. “The treatment will protect the tree for several years, as many as 5 to 7 years. It does not affect other insects or invertebrates that might use the tree for shelter or habitat, but do not feed on the tree. It also does not affect vertebrates or other plants.”
A hemlock branch infected with Wooly Adelgid. You can see the infection at the base of the needles.
Renfro said partnering with other organizations such as HRI helps HCLT to expand staff capacity. HRI has helped HCLT and numerous other organizations across WNC to access and manage their hemlock populations across the state. They are now also responsible for managing hemlocks in both Pisgah and Nantahala USFS Ranger Districts.
Shows a size comparison of a woolly adelgid and a penny.
“Without the help of their treatment teams it would take us weeks if not months to treat all of our surviving hemlocks,” said Renfro. “We can accomplish more together as we all strive to be better stewards and neighbors in this special corner of the world.”
The chemicals used to treat hemlocks include imidacloprid and dinotefuran. Wallston said purchasing these chemicals and providing the treatment was funded in part from a grant from Mountain Findings in Highlands.
Additional funding came from grants from the NC General Assembly/NCDA&CS and a USDA Forest Service Landscape Scale Restoration (LSR) grant in partnership with the NC Forest Service Forest Health Branch.
Hemlocks that needed to be treated that were too close to other trees had the chemical sprayed along the trunk instead of applying it to the base of the tree.
“I feel confident that we have taken great strides in making a difference for our trees,” said The Mountain Executive Director Steph Anderson. “We will also be using both of these opportunities to teach the importance of caring for our land with many of our members and retreat participants.”
Wallston said this type of treatment is crucial to prevent the decline of hemlocks.
“They are considered foundation species that drive entire ecosystems and play a particularly important role in the riparian zones that line our mountain streams,” she said. “No other tree species can replace them and offer the multitude of services that a healthy stand of hemlocks provides.”
To learn more about the Hemlock Restoration Initiative, click HERE.
To learn more about what you can do to save hemlocks on your own property, click HERE.