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Is there Hope for our Hemlock?The Hemlock Woolly Adelgid is in the mid to late stages of destroying the Eastern Hemlock throughout the Southern Appalachians. DuPont State Forest depends on both the Carolina and Eastern Hemlock to provide deep shade for its cold water trout habitat. Friends of DuPont Forest is deeply concerned about the decline of DuPont's hemlocks, and is working with Division of Forest Resources (DOFR) staff on several projects. FODF has assisted DOFR staff in releasing Sasi beetles, which are a natural predator of the HWA pest. FODF has also funded the release of the Sasi beetles on a private hemlock ecosystem directly adjacent to DuPont State Forest. FODF volunteers have recently begun assisting DOFR staff in monitoring the effectiveness of both the biological controls (Sasi beetle) and chemical controls (which are targeting several hundred individual specimens throughout the Forest for survival). Like DuPont State Forest, the Great Smoky Mountains National Park is engaged in both predator beetle releases and chemical control of individual specimens (see the Great Smoky Mountains National Park HWA page). However, as everyone involved admits, chemical controls are only a stop-gap measure to preserve a relatively small number of specimens. Any hope for survival of the rich cove ecosystems that the hemlock provide rests in the success of some form of biological control. Biological Control Efforts by the US Forest ServiceThe US Forest Service is working from Georgia to Maine with local universities and agencies to experiment and release the Sasi and several other beetles that are predators of the HWA. However, it seems to be very difficult to assess the degree to which these biological controls are effective. First of all, the predator beetles immediately scatter to tree tops, making documenting their survival and effectiveness nearly impossible. Second, varying seasonal temperature and drought conditions cause dramatic swings in HWA and beetle populations, confounding most data analyses. Such lack of hard evidence of biological efficacy, combined with the tragic decline of hemlock stands throughout much of the Appalachian range has led many in the USFS and elsewhere to promote chemical treatment to save remaining high profile hemlock stands. However, it is important to note that the USFS and other affiliated agencies are still researching and breeding several types of predator beetles in hopes of finding a more effective biological protocol. See the USDA and US Forest Service web sites on the subject.. Few options for private landownersUnder current regulations, beetles raised in labs that are funded by the USDA can only be released on public lands. Unfortunately, the supply of beetles available from commercial sources for release on private lands is extremely limited/ Saving Hemlocks - Hope for Private LandholdersA growing number of researchers and volunteers are working to promote the use and evaluate the effectiveness of biological controls to save the HWA-infested hemlocks on private land in western North Carolina. Patrick Horan, a retired professor living in Sapphire, NC, has formed Saving Hemlocks to promote the release of the Sasi beetle on private land, having observed encouraging results around Transylvania County. Saving Hemlocks has developed a new hemlock health assessment technique that involves digital photography to determine the optical density of the crown foliage. Using these new techniques, Saving Hemlocks has documented the recovery of hemlocks on private land treated with as few as 50 - 100 Sasi beetles per colony. USFS release criteria demands a minimum of 1000 beetles per colony on public lands. Because Sasi purchases from private labs cost greater than $2 each beetle, Patrick's recommended protocol, if confirmed, would represent a significant breakthrough for private groups struggling to protect their hemlocks. Saving Hemlocks has recently launched a new website SavingHemlocks.org, to document their protocols and success stories. The site also highlights encouraging research from researcher Carole Cheah about the correlation of Sasi beetle releases in Connecticut with their now stabilizing hemlock stands. Friends of DuPont Forest will continue to work closely with DOFR staff to assist however we can. We will also be following Saving Hemlocks efforts closely to learn the results of the tens of thousands of Sasi that the group has released locally so far.
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