2024-2025 Treatment Season Accomplishments

By Alicia Walsh, HRI Forestry Crew Leader

As with innumerable other pursuits in our mountain communities, our treatment season this year was deeply affected by Tropical Storm Helene. After a delayed start date, our first order of business was to assess the accessibility and health of the hemlock stands we had planned to treat this season. In order to maximize our ability to treat hemlocks while most of our partners on state and nearby national forest lands were focusing on emergency storm damage repair, we focused our early fall treatments on Nantahala National Forest.

After our success at Panthertown, our crew focused on assessing the health of our hemlock stands closer to home. In late fall, we returned to DuPont State Recreational Forest (DSRF) to assess the health of our hemlock conservation areas (HCAs) and to report on trail damage and overall forest health. Despite some areas of heavy storm damage, we were heartened to find that overall, our hemlocks remained healthy and intact. We were even able to locate and treat a new hemlock conservation area, adding an additional 208 protected hemlocks to over 12,000 hemlocks currently protected from HWA in DSRF.

Moving into the winter months, we were able to access and assess our HCAs in the Green River Game Land, Sandy Mush Game Land, and the North Carolina Arboretum. Despite some extreme storm damage, and some issues with access, we were able to treat a total of 2,229 hemlocks by the end of February.

Meanwhile, our NC Forest Service (NCFS) Forest Health partners, with the help of the BRIDGE program, shifted their priorities to assisting with Hurricane Helene recovery efforts, limiting their hemlock treatment efforts. The BRIDGE crews led efforts to clear roads and push through brush. In the midst of this work, they made time to return to Hemlock Bluffs Nature Preserve, in Raleigh, North Carolina to re-treat over 100 eastern hemlock trees. This disjunct population of hemlocks is unique to the piedmont region, and has persevered in the region due to the north-facing bluffs around Swift creek, which provide a sheltered environment where many species endemic to the Appalachian mountains have been able to thrive.

In the spring, our state faced extreme wildfire activity, further limiting hemlock treatments on our state lands. Despite these setbacks, the NCFS and BRIDGE were able to treat close to 2,000 hemlocks this spring season, including over 200 Carolina hemlocks.

The Black Cove and Deep Woods fire burned through many of our hemlock conservation areas in Green River Game Land. Once the fire was controlled, our forestry technicians went into the affected sites to survey the damage to our hemlock stands. Hemlocks are vulnerable to fire, but we were happy to find that a majority of the mature hemlock trees in our HCAs remained standing, although they showed a range of damage to their trunks and lower branches. Severe fire temporarily limits a tree’s ability to absorb nutrients and water from the “duff,” or surface layer of the forest floor. This has the potential to prevent the hemlocks in our stands from absorbing the insecticides we use in our treatments. In an effort to better understand the impacts of fire on the effectiveness of our hemlock treatments, and the lasting health of hemlocks in our stands, we have created multiple “burn impact plots” in the Green River Game Land HCAs that have had varying levels of damage due to forest fires. Monitoring of these plots over the next few years will inform us on how to best manage hemlock stands that have been impacted by forest fires. In addition to this work, we continued to assess existing HCAs for the presence of HWA predators. We did not recover as many Laricobius beetles as in prior years, but they were still present at most of the sites we surveyed.

In order to avoid working in sites impacted by fire, HRI’s crew spent most of March at two of our more eastern sites: Stone Mountain State Park and Hanging Rock State Park. These sites were last treated 5-7 years ago by our crew. It was wonderful to return to these previously treated areas and see how healthy the hemlock stands were. We were also delighted to find Laricobius nigrinus beetles at both Stone Mountain and Hanging Rock State Park, as there had been no previous documented releases of that species in those places. Our crew enjoyed the warmer weather and unique granite outcrop ecosystems found at both of these beautiful state parks. One of our favorite treatment sites this season was Hanging Rock State Park, where we treated 224 Carolina hemlocks along Moore’s Knob. Moore’s Knob is the highest mountain in the Sauratown mountain range, which are themselves a surviving remnant of the Blue Ridge Mountains. The Carolina hemlocks found along this mountaintop are a reminder of the Sauratown mountain range’s ancestry. Our crew was amazed by the views at the lookout tower on Moore’s knob, which stands so tall that you can see the skyline of Charlotte, over 100 miles away.

Another focus of our spring season was engaging with our wonderful volunteer network across Western North Carolina; we were able to coordinate twelve volunteer treatment days this spring! It was amazing to see the community efforts to support our work both locally at the North Carolina Arboretum, Green River Game Land, Montreat and DuPont Recreational State Forest, and at our more remote treatment locations in Hanging Rock State Park, Stone Mountain State Park, and Nantahala National Forest. In total, volunteers helped us treat an impressive 2,870 hemlocks, which represents about a third of the total number of trees treated this season.

Our last overnight treatment trip of the season involved the help of determined volunteers, who joined us as we once again trekked into the backcountry of Panthertown Valley. This time, our focus was on treating the Carolina and eastern hemlocks that grow beside one another along the cascading creeks and waterfalls found in the western portion of the Panthertown wilderness. These hemlocks are not known to have ever been treated before, and most of them required stem injection treatments, which is a costly, time-consuming method of treatment we don’t often use in our program. However, it is the most environmentally responsible way to treat hemlocks that are growing directly over water, as these hemlocks do. In order to complete this project, we relied on the help of professionals from Rainbow EcoScience, as well as volunteers from other conservation organizations, including the Appalachian Trail Conservancy, Friends of Panthertown, and Friends of DuPont Forest trails crew. This was an incredibly successful project. Over the course of three days we were able to treat 203 hemlocks, including 62 hemlocks treated with stem injection. These hemlocks stabilize the banks along over 1 mile of steep streambanks and waterfalls and provide the shade necessary to the native brook trout that spawn in the stream waters. Thanks to the effort of our crew and everyone who helped, these hemlocks will continue to provide these ecosystem services for years to come. The success of this project was the result of many years of planning and coordination with our partners, including NCFS, who loaned us extra stem injection equipment for the project.

Despite multiple natural disasters limiting our ability to work in many of our conserved natural areas this year, our treatment team was able to adapt and focus on the positive impacts we were able to have across western North Carolina. In total, HRI treated 8,709 hemlocks across over 1,000 acres of protected lands, including the establishment of six new hemlock conservation areas on over 100 acres of newly protected land. Our team’s dedication and resilience was evident this season, and we are incredibly proud of all the work we were able to accomplish. We are looking forward to an even busier treatment season this upcoming year, with a great team of dedicated staff working on both public lands and with private communities via cost/workshare projects. We are incredibly grateful for the support of our partners, volunteers, and community as we continue to grow and expand our treatments into new hemlock conservation areas.

Interview with Greg Wiggins of the

Beneficial Insects Lab

Greg Wiggins is the Biological Control Administrator for the Beneficial Insects Lab in Cary, North Carolina. The Beneficial Insects Lab is part of the Biological Control Services of the North Carolina Department of Agriculture and Consumer Services (NCDA&CS). Biological Control Services implements and maintains biological control programs to benefit the residents and the environment of the state of NC.

Former HRI Outreach Manager, Caroline Lord interviewed Wiggins for the Winter 2024 newsletter where they discussed protocols at the lab and the Laricobious osakensis beetle. Part 2 of this interview was featured in the Summer 2024 newsletter. This interview picks up where that one left off with topics such as two predator species of silver fly and eDNA. 

Can you tell me about the lab’s work with the silver fly?

The silver flies have been released in the Eastern U.S., but researchers have had trouble recovering them in release sites, even within sleeve cages, where they wanted to contain them to see how well they survived over winters. 

How do you remedy that?

In Bent Creek, we’re now using whole tree cages in which we release the flies so that they have access to the whole canopy of the hemlock tree. By caging the whole tree, the flies have some room to fly in and out of the canopy and around the tree inside the cage. This allows them to have a mating flight or some other behavior that may not be possible in sleeve cages. We’re seeing if using those large tree cages, the silver flies are able to better establish. This spring we were able to release many more flies per cage (about 300) than the previous releases (30-50). We hope these greater release numbers will enhance establishment. 

What effect does the silver fly have on hemlock woolly adelgid?

The silver fly is another spring/summer predator on the spring/summer generation of hemlock woolly adelgid. It will be another predator in the complex of natural enemies that we’re trying to establish to exert pressure to lessen the levels of hemlock woolly adelgid on trees. So every little bit of predation could help in maintaining the health of the tree by reducing hemlock woolly adelgid populations. 

Are you studying just one species of silver fly?

There are two species of silver fly, Leucotaraxis argenticollis and Leucotaraxis piniperda, and depending on which species is present in the system, they can emerge at different times peaks in the season. So depending on when that peak occurs in the year, I think argenticollis can feed on both the sistens (winter) generation and argenticollis can have a later peak as well and feed some on the progrediens (spring/summer) generation. Piniperda feeds primarily on the spring/summer generation. Its peak occurs when  HWA is maturing in mid-April, and the piniperda can feed on the eggs. 

How was the silver fly discovered as being a good agent for biological control?

During the course of searching for adelgid predators on hemlocks in the western part of North America, different researchers were collecting foliage to see what kinds of predators were present. That’s how they found Laricobius nigrinus but they also consistently collected  Leucotaraxis flies from western hemlock species when they did those surveys. 

I’ve recently learned about the application of environmental DNA, or eDNA, in your work. Can you tell me more about it? 

Environmental DNA is a term used for residues of DNA left by species in the environment. In the case of Leucotaraxis, eDNA sources can be frass, old larval or pupal skins, or body parts from dead flies. A group from Cornell is supplying us with Leucotaraxis flies for release and supplying us with protocols to conduct eDNA sampling within our release cages in our large field cage study. Because the application of using eDNA is relatively new to the hemlock system, our methods are still being worked out in cooperation with the Cornell staff. We’ve tried different techniques of clipping the foliage and rinsing it or rinsing it on the tree and collecting the rinsed water and shipping the rinsed water for analysis. We want to try different methods of collecting that eDNA that will give us the highest resolution or the highest detection, and the methods are still being worked on. 

How do you currently monitor for the silver fly? 

The conventional monitoring is branch clipping and holding foliage in traps to monitor for fly emergence over time as well as visually examining the foliage. So now we’re using three different monitoring techniques to detect the flies we’ve released in these cages and eDNA is one of those. 

How does eDNA add to or possibly change the current methods? 

The whole reason we would want to enhance eDNA methodology and its detection strength is to have a good protocol that would get consistently high detection rates. Then it would be easier to sample throughout the region for the presence of different predators in the system without having to see those predators. The eDNA would pick up traces of the predators’ DNA that are on the foliage, and we wouldn’t have to take predators out of the field, store them in alcohol, look at them under a microscope or run molecular analyses to confirm what species they are. We could pick up traces of their DNA and confirm them from this method. It’s a lower impact method on the predator populations if we can enhance it to the point where it is effective and has a higher resolution of detection.

Note of acknowledgement: This season (2024-2025), the releasing and monitoring of the Leucotaraxis flies has been conducted by Bud Mayfield, Bryan Mudder, and Ben Girgenti, US Forest Service Southern Research Station. Leucotaraxis flies have been supplied to the Beneficial Insects Lab by Mark Whitmore and Tonya Bittner, Cornell University, and Aryanna James and Mary Hoffman, Virginia Tech University. This work would not be possible without funding from Rusty Rhea, US Forest Service, Forest Health Protection.

The Lingering Hemlock Project

By Olivia Hall, HRI Educational Outreach Manager & Lingering Hemlock Project Outreach Coordinator

As an organization, the Hemlock Restoration Initiative (HRI) has always been proud to have an education component to our mission on top of our active management role. Since 2015, HRI has been educating landowners, natural resource managers, and the public about hemlocks and how to protect them from the hemlock woolly adelgid (HWA). This education and outreach background set us up to begin outreach for a project that is larger than our humble organization and our WNC home: The Lingering Hemlock Project. 

As most of you reading this story are aware, the eastern hemlock (Tsuga canadensis) is threatened by the hemlock woolly adelgid (Adelges tsugae) & the elongate hemlock scale (Fiorinia externa). There has, of course, been a considerable effort to conserve hemlock in its range in the face of these pests, each method an important piece of the puzzle. Chemical control, especially, as the most effective method available to us right now, is widely utilized by HRI during our management of hemlocks on North Carolina public lands. However, chemical control is not sustainable in the long term, in the sense that hemlocks must be treated one by one and it must be repeated. This is difficult, if not impossible, to keep up indefinitely. Biological control is another promising solution, but it is still in development, and cannot currently be depended on. In the meantime, we need to continue to explore other solutions. That is where the Lingering Hemlock Project comes in. Each partner involved in the Lingering Hemlock Project, including HRI, is playing a different role in the development of HWA-resistant hemlock trees–an ambitious but promising goal.

The Lingering Hemlock Project is a subset of Tree Species in Peril (TSIP), a project led by The Nature Conservancy (TNC), which aims to to protect eastern tree species that are threatened by invasive pests and pathogens through resistance breeding programs. TSIP partners are from universities, government agencies, non-profits, and other private organizations across the east coast, with disciplines ranging from research to app development to education to forestry. Collectively, they are working to find long-term solutions to protect ashes, beeches, and hemlocks from the invasive pests decimating their populations. Of course, as a hemlock-centered organization, HRI’s involvement is restricted to the hemlock portion, which will be the focus of this article. However, if you’d like to hear more about the awesome work that is being done with the other species, you can read about that here. 

Lingering Hemlock Project

One of the driving purposes of the Lingering Hemlock Project is to determine whether and to what extent there is heritable HWA resistance in hemlocks, and if so, what the best criteria will be to reliably detect it. To accomplish this, project partners, such as land trusts, foresters, and academic institutions, will search for ‘lingering hemlocks’, or hemlock trees that are still alive in locations where forest-wide hemlock mortality has already reached 80% or higher. These ‘lingering’ trees may not be in pristine condition, but their relatively higher survivorship may be important in understanding and breeding resistant hemlocks. In locations where hemlock mortality has not yet reached 80%, project partners will set up long-term “hemlock health monitoring plots,” in which hemlocks will be monitored for decline alongside other environmental and site characteristics. Monitoring hemlock decline over time and space in this way will allow us to better understand patterns of hemlock mortality across the landscape. By installing these plots, we expect to be able to understand HWA’s spread and severity across its leading edge and in doing so, catch 80% hemlock mortality as it occurs. Once hemlock mortality reaches 80% in these plots, any remaining hemlocks will then be documented and reported as “lingering hemlocks.” 

Once these potentially resistant hemlocks have been identified in the wild, research partners will receive submission data directly from the app in order to further study the candidate trees, both genetically and experimentally, to learn more about the mechanisms behind HWA resistance in hemlock trees and to ascertain the degree to which they exhibit resistance. Then, using the knowledge gained by the research on genetic resistance and the gene(s) identified as resistant, the process of developing nurseries of resistant hemlocks can begin. Through cross-breeding, TSIP partners hope to amplify the qualities found in the resistant, wild hemlock trees, and thereby accelerate hemlocks’ evolution of HWA resistance. Ultimately, this genetic stock would then be used to re-seed and restore areas that have faced broad hemlock mortality, preventing the loss of the species from the landscape.

The Hemlock Restoration Initiative’s role in the Lingering Hemlock Project centers around the goal of finding and training appropriate audiences to use the lingering hemlock search protocol to find hemlock trees that could be used in the breeding research. We have been busy creating outreach materials, giving presentations, attending conferences to speak about the project, leading lingering hemlock identification workshops, and working with a local production company to create a series of videos that will promote the project and serve as training aids.

This project is an exciting but long-term endeavor. Because of hemlocks’ relatively long lifespan and generation cycles, this project will be ongoing for decades to come. It will require the help from partners in all parts of the eastern hemlock range, from northern Alabama to Maine, Wisconsin, and Canada. And the time to ramp up this search is now! We expect most lingering hemlocks not to be fully resistant, and thus will continue to disappear from our forests over time. We need to find them before they become lost to us forever, and we need all the help we can get.

If you are interested in helping with this project, please contact Olivia Hall at education@savehemlocksnc.org to learn about how you can get trained. Continuing Forestry Education credits are available for participating in a Lingering Hemlock ID training. We are especially looking for people who already have a basic knowledge about hemlock ID and ecological processes, are in the forest on a regular basis, and know the land they work or recreate in. 

Volunteer Spotlight: Miriam Allen

By Ayla Busch, HRI Community Engagement Manager

The Hemlock Restoration Initiative could not do what we do without the help of our hard-working volunteers. Each newsletter we like to highlight the contributions of our volunteers. In this issue we would like to recognize Miriam Allen.

A self-described “wilderness junkie,” Miriam grew up attending wilderness programming as a child and fell in love with the critters, plants, and landscapes that surrounded her. In her 20s, she spent time backpacking in different areas of the world, including the South American Andes and the Rocky Mountains. Even after spending time in natural areas all over the globe, Miriam confidently states that the Appalachians are her favorite mountains “because there’s so much… diversity in the [Appalachian] forest.” 

Miriam moved to western North Carolina about 25 years ago, and has been learning about and observing everything in our region’s natural areas ever since. “I remember when there wasn’t Japanese Stiltgrass all up the mountains. I remember first seeing it, and going ‘What is that?’ …Here we are, 20 years later. [Invasive plants] have absolutely taken over.”  As soon as you meet Miriam, it’s apparent that her deep love of the native Appalachian ecosystems is what drives her intense passion for volunteer work.

Miriam first got involved with HRI in 2016, when she volunteered to chemically treat hemlocks in Sandy Mush Game Land on HRI’s first ever volunteer workday! She has since been a dedicated HRI volunteer, contributing over 50 hours of service on public lands throughout western North Carolina. She shared how much fun it is to connect with the crew members and learn from everyone, declaring, “I am a groupie for biologists!” Crew members who have worked with her know that Miriam loves to scramble up and down steep slopes and across rugged terrain. She’s always eager to treat as many hemlocks as possible!

The most rewarding part of volunteering with HRI for Miriam is getting to see the old growth forests. She remarked, “I feel super grateful to HRI for having had the opportunity to go and see some of these forests that…I never would have seen otherwise. It’s been an incredible opportunity.” While volunteering with HRI, Miriam got the rare chance to visit the largest known living eastern hemlock in the world. Miriam said of the experience, “That was by far the coolest old growth forest I have ever been to in North America or South America or anywhere. That patch of hemlock stands was so great!” Don’t ask her where this protected hemlock stand is, though – like any good naturalist, she’s honoring a promise not to disclose its location. 

Miriam also generously donated her time and Spanish language skills to translate many of HRI’s outreach materials into Spanish! Thanks to her, we can disseminate information in Spanish at community events or digitally to anyone who wants it. In her volunteer career with HRI, Miriam is most proud of getting to name the hemlock tree “el hemlock” in Spanish. 

When she’s not spending time outside as a naturalist or helping us treat hemlocks, Miriam is playing music. Her music community was what first drew her to Western North Carolina – she’s been a professional musician in this region for 25 years. When HRI asked for our newsletter recipients to send in tree stories in the wake of Tropical Storm Helene, Miriam responded with not just a story, but a song. Titled ‘Queen of Buncombe County,’ the song, written with a handmade redwood top guitar donated to Miriam by a luthier, explores “how [Helene] would have been different if we hadn’t clear-cut the French Broad River Valley.” See some of our favorite lines below: 

To check out more of Miriam’s music, visit her website or find her on Spotify.

As a woman of many talents – including jeweler, sailor, builder, and former home inspector –  we’re excited to see how Miriam continues to bring her energetic and creative personality to her HRI volunteer endeavors!

If you’ve been thinking about volunteering with us at HRI, take Miriam’s advice – “Just do it! Go get dirty…and let the biologists be your guide.” Contact Ayla Busch at volunteer@savehemlocksnc.org to learn more about volunteer opportunities with HRI.