Help For The Hemlocks

Our hemlocks face a serious menace. A diminutive but deadly insect invader, the hemlock woolly adelgid, now threatens the watershed forests of our region. Photo by Becky Nystrom

A week ago, a hardy group of volunteers kicked off our 2017 CWC/RTPI/JCC Hemlock Wooly Adelgid survey season in frigid conditions at Chautauqua Watershed Conservancy’s Dobbins Woods Preserve on Bly Hill Road in Ashville, checking for a tiny but frightening threat to our beloved hemlock forests. On Friday, we surveyed CWC’s Cassadaga Creek Preserve in Stockton, and this coming Saturday we’ll visit CWC’s Elm Flats First Preserve. Additional sites await our attention in the next two months – and you are welcome to join us! What are we looking for? Why the concern? How can you help?

The Eastern Hemlock (Tsuga canadensis) is a widely distributed, long-lived, and lovely native evergreen tree whose dense conical shape, delicately needled branches, and shade-tolerant lifestyle contribute to its special role as a “foundation species” in our local forests. Hemlocks provide unique ecological gifts and critical underpinnings for the tapestry of woodland life, creating complex habitat impacting community structure, resilience, and biological and hydrological dynamics. Typically associated with deciduous hardwoods such as sugar maple, red maple, American beech, yellow birch, and northern red oak, only the dense stands of low-branching eastern hemlock provide year-round food, oxygen, thermal cover, and refuge for wildlife, and sustain distinctive soil microbes within the sphere of their extensive and shallow root systems. Hemlocks efficiently absorb and retain rainwater and snowmelt, reduce soil erosion, stabilize stream banks, and uniquely regulate the water chemistry, flow rate, and temperature of streams and rivulets meandering beneath their boughs. Hemlock forest streams support distinctive and desirable communities of macro-invertebrates, amphibians, and fish. Brook trout, for example, are three times more likely to occur and four times more abundant in streams draining hemlock forests compared to those draining hardwood forests (Snyder, et. al., 2005). Likewise, the damp, dark, terrestrial microclimate of hemlock forests promotes certain insects favored by blackburnian and magnolia warblers, flycatchers and vireos, birds found more often in hemlock stands than anywhere else. The hemlocks’ low-branching habit provides protective winter cover for white tailed deer, ruffed grouse, and turkey, and countless seeds from their tiny cones nourish hungry juncos, pine siskin, mice, and squirrels. At least 96 species of birds, 47 mammals, and 215 insect species are known to be associated with these invaluable forest trees.

But the hemlocks face a serious menace and need our help! A diminutive but deadly insect invader, the hemlock woolly adelgid (HWA), now threatens the watershed forests of our region. HWA is a non-native, aphid-like insect accidentally imported to Virginia from Japan in the 1950s. Unlike Asian hemlocks that have co-evolved alongside this pest over thousands of years, eastern hemlocks have little natural defense against HWA. Piercing the base of hemlock needles and hiding within tiny white cotton-ball-like woolly masses, HWA steals critical sugars and leads to twig loss, slow starvation, and death. In the last few decades, this lethal little sucker has decimated nearly all mature and old-growth coastal zone hemlocks from Rhode Island to New Jersey and is now spreading rapidly throughout the eastern United States. HWA is closing in – recently discovered local infestations include those in Zoar Valley, Allegany State Park, and SUNY Fredonia College’s campus forest.

So what can be done? Awareness and early detection are key. For the third year in a row, the Roger Tory Peterson Institute, Chautauqua Watershed Conservancy, and Jamestown Community College are undertaking a series of winter field surveys and educational programs, and we encourage your participation. Training is provided on site. During the months of January and February, our collaborations will take us to high density hemlock areas within public lands and several of CWC’s beautiful forested preserves, and we’ll search for the presence of these unwelcome intruders among the needles of our hemlock friends. Our remaining 2017 survey schedule is as follows: Saturday, Jan. 21 at 9:30 a.m. at the CWC’s Elm Flats First Preserve; Friday, Jan. 27 at 12:30 p.m. at the NYS DEC South Valley State Forest; Saturday, Feb. 4 at 9:30 a.m. at the NYS DEC North Harmony State Forest; Friday, Feb. 10 at 12:30 p.m. at the JCC/RTPI Forest Preserves; Saturday, Feb. 18 at 9:30 a.m. at the Warren County Hatch Run Conservation Demonstration Area; and Friday, Feb. 24 at 12:30 p.m. at the CWC’s Goose Creek Valley Greenway Preserve.

For each Friday survey, please meet at the RTPI parking lot at noon to facilitate carpooling to the site. For each Saturday survey, please meet at the site. Individuals interested in participating in our surveys should be prepared for cold, wet, and snowy conditions and wear warm layered clothing and boots. Snow pants and snowshoes or cross-country skis are highly recommended when snow pack is deep. For more information and directions, visit or Questions may be directed to RTPI Conservationist Elyse Henshaw at or 665-2473, ext. 231, or CWC Conservation Lands Manager Jonathan Townsend at or 664-2166.

Becky Nystrom is a Professor of Biology at Jamestown Community College, a long-time CWC supporter and volunteer and a founding trustee of the CWC. The Chautauqua Watershed Conservancy is a local not-for-profit organization that is dedicated to preserving and enhancing the water quality, scenic beauty and ecological health of the lakes, streams, wetlands and watersheds of the Chautauqua region. For more information, call 664-2166 or visit or