With hemlock woolly adelgid (HWA) moving into the SLELO area, some readers may soon be looking at HWA on their property and wondering “now what?”. Especially if you own more than a few hemlocks, figuring out the next steps can be daunting. Fortunately, there are resources available to help you think through your response to HWA, and the New York State Hemlock Initiative is NYSHI with Cornell University is here to help. Below are some questions to consider for managing HWA. Please visit the NYS Hemlock Initiative website or reach out to the nyshemlockinitiative@cornell.edu for further information.

Question 1. Is this HWA? There are lots of resources to help identify HWA. The New York State Hemlock Initiative website has handouts and videos for HWA identification for you to use to confirm the presence of HWA.

Question 2. Oh, no, this is HWA. What next? You may be asking yourself, is the treatment to save my hemlocks worth the risks of using chemicals on my property? This is a personal decision, but whatever decision you make, remember that mortality rates of hemlocks with HWA are very high, and you need to weigh the impacts of treatment against the loss of hemlock from your property. Dr. McCarty of the University of Georgia has been researching the impacts of chemicals used to treat hemlocks for HWA since 2015 and has put together a thoughtful publication covering all the impacts of treating hemlocks she and others have found so far. While Dr. McCarty has found some impacts of treatment, the impacts of losing hemlocks from an ecosystem have been far greater. McCarty’s take-home message is that ecosystems are less disrupted by treatments to conserve hemlocks than they would be due to a loss of hemlocks because of non-treatment.

Question 3. I have way too many hemlocks to save them all. Which ones do I save?

The answer to this depends on a lot of factors. How much hemlock is on your land, and how dense is it? What’s likely to replace the hemlock when they die? Do you have rare species that will lose critical hemlock? Do you have trout in streams on your property? Are you financially able to save your trees? All these questions and more factor into which hemlock trees to save on your property. The NYS Hemlock Initiative has toolkits for landowners and regional land managers to help think through these questions. If you are planning for a single property, just reading through the linked documents at the bottom of the Landowner Toolkit page will help you think through what factors are important to you on your property. If you are managing many sites or working on saving hemlocks across the landscape (perhaps with a lake association or Soil and Water Conservation District), the included Excel file at the bottom of the Regional Hemlock Toolkit page may help guide decisions. NYSHI staff can assist groups as they consider large-scale hemlock conservation.

Question 4. What else can I do to help?

As we begin to see mortality from HWA in our area, tracking tree mortality across the region will allow us to identify any hemlock that stay healthy after HWA has killed most hemlocks. These ‘lingering hemlock’ may have some traits that would help tree researchers develop HWA resistant hemlock. The Nature Conservancy’s Tree Species in Peril project is supporting research on invasive species-resistant strains of five tree species from the Northeastern US, including eastern hemlock. If you are interested in setting up a hemlock mortality plot to help the search for lingering hemlock, please reach out to Grace Haynes at gh447@cornell.edu.