Conservation Commission Fall ’24 Projects:

* Restoring Native Vegetation along Town Roadsides 

* Protecting Hemlocks from Hemlock Wooly Adelgids

Come learn about both projects and ask questions at a
Conservation Commission Community Conversation
on Monday, August 12 from 6:30 – 8:00pm
In the Spinning Room of the Granite Mill

What are these projects? Harrisville Conservation Commission is launching two important projects this fall the to help restore the balance of nature in Harrisville.

The first is a long-discussed initiative to restore native vegetation along Town Roadsides by removing invasive plants that have been crowding it out. Invasives are plants that spread quickly and out-compete native vegetation for resources.

The second is an effort to reduce populations of an insect that is threatening our local forests, the Hemlock Wooly Adelgids, which are spread throughout town woods. They are particularly threatening to Hemlock trees, but also weaken other evergreen species. They have a natural predator that is found locally but is only seen at low levels to date. The plan is to augment local populations of these predators to control Hemlock Wooly Adelgids and reduce their populations to sustainable levels so they will not kill off important tree species.

For more information read the brief synopses below and follow the links for as much detail as you wish to review.

Join us on August 12 from 6:30 to 8:00pm in the Spinning Room at the HHI Granite Mill for a Community Conversation about the two programs and the methods used to accomplish them.

Restoring Native Vegetation along Town Roadsides:

Why: Native vegetation provides habitat for native insects and small animals, and serves over 250 types of native bees that pollinate many varieties of plant life.

How: Kill Japanese Knotweed, a powerful invasive that spreads quickly and displaces native vegetation. Method based on results of organic/inorganic herbicide tests conducted in 2023.

When: late September, post-flowering to protect bees, when sap flows down to be stored in roots for winter.

Click links for more info:

Knotweed Locations on Town Roads (2018 survey – click for Google Map Interactive views of photos)

Harrisville Con Com Summer 2023 Tests of Organic & Conventional Herbicides

NH Dept. of Agriculture Guidelines for Knotweed Removal (Quick Form – 2 pages)

NH Dept of Agriculture Best Practices Manual for Removing Japanese Knotweed (15 pages)

Example: Town of Durham, NH Knotweed Control Program

Protecting Hemlocks from Hemlock Wooly Adelgids

Why:  Hemlocks are a vital forest resource

Hemlocks provide shelter and food in winter for deer, small animals and birds. Hemlocks keep streams cool; Hemlocks absorb far less groundwater in drought, unlike deciduous trees

Hemlock Wooly Adelgids are killing our local hemlock trees. When you suddenly see a severely weakened or dead hemlock trees, look closely at its needled branches. When Hemlock Wooly Adelgid infestation levels rise above 30% of tree branches they can kill healthy mature trees in 4 to 7 years. Many landowners are finding dead hemlocks on their property in Harrisville.

Hemlock Wooly Adelgids used to die off in -20 degree winter weather. Our climate is warmer now, and winters are warming even faster than summers. Today Hemlock Wooly Adelgids are growing out of control and are found in all our Hemlock woods. While not as deadly on other trees, they also attack White Pine, Balsam, Larch and other trees.

Dead trees near homes are a danger to life and property, and costly to remove (I’ve lost 3 large hemlocks in 3 years on a small ¾ acre lot – cost about $3,000 for removal). Landowners lose valuable forest inventory and forests are less healthy when species are removed from their naturally balanced populations.

How: Augment local populations of Laricobius nigrinus beetles, predators of HWA

Laricobius nigrinus beetles are natural predators that exclusively feed on adelgids. Hemlock Wooly Adelegids are invasive aphid-like insects that were inadvertently brought east from the Pacific Northwest in the 1950’s. Researchers at the University of North Carolina realized that Laricobius nigrinus beetles were helping to keep adelgid populations under control in the Pacific Northwest. For the past 20 years they have been gathering Laricobius nigrinus beetles out west and releasing them in NC Hemlock forests where large areas are now recovering from HWA predation.

This approach to restoring a balance in nature is referred as Biocontrol. Unlike pesticide methods like spraying and fertilizing specific trees, Biocontrols establish a lasting balance in nature. Local releases of of Laricobius nigrinus were first done over 10 years ago in Hancock by the NH Forest Health Bureau working under a federal license from the USDA, but it wasn’t clear that the populations had survived the winter environment.

Conservation Commission member Ralph Zingaro, a Research Horticulturalist trained at Cornell, discovered local populations  of Laricobius nigrinus on Noel Greiner’s land this spring proving that not only could populations survive but they were able to spread by about 2 miles per year.

Harrisville Conservation Commission has received a letter of permission and support from the NH Division of Forests & Lands Forest Health Bureau for this project allowing us to work under the State of New Hampshire’s permit from US Department of Agriculture do these releases. The Forest Health Bureau will oversee the releases by inspecting beetles prior to release to ensure that only Laricobius are in the release batches.

Two other Conservation Commission members, John Sandri, an arbiculturalist (tree care) also trained in soil science, and Don Scott, a Landscape Architect with 10 years of experience in environmental restoration, have used computer mapping tools to generate lists of potential release sites. Our goal is to find sites best suited to Laricobious survival and spread across town to create local populations of Laricobius nigrinus that can thrive and protect our Hemlock trees. Over time our project may benefit the entire region.

When: Beetles will be released in late October / Early November 2024.

Click link for more info: BEETLES SAVE NEEDLES  – a detailed explanation of the problem and solution methods

          Submitted by Harry Wolhandler, Chair, Harrisville Conservation Commission

About the Conservation Commission
The Harrisville Conservation Commission protects and preserves vital natural resources, including woodlands and wildlife, agricultural land, wetlands, healthy lakes, and native vegetation along roadsides, as well as community access to nature.

Our charter includes:

• Advising other town boards and committees on environmental risks worthy of attention;
• Offering public education to help neighbors make reasonable environmental decisions as a community;
• Conserving land by facilitating conservation easements and providing oversight; and
• Taking action where feasible to deal with specific environmental problems.

Join the Conservation Commission and work with us!  If you have interest in these areas, we’d welcome your leadership as we work together on behalf of the town:

• Woodland and agricultural management
• Wildlife preservation whether as an environmentalist, hunter or fisherman
• Optimizing community growth and development in ways that support future generations as well as our town

The HCC meets at 7:00 pm on the first Wednesday of each month, both in person at town hall and online over zoom. Links to agendas and meetings are posted in the right hand column on https://harrisvillenh.org.

For information contact HCC Chair Harry Wolhandler at 603-852-8026 or harry@accelara.com.

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• Rain Garden at the Harrisville Pond Boat Ramp

  • The Rain Garden is a project of the Conservation Commission that protects Harrisville Pond from pollution caused by winter sand and salt, and allows storm runoff waters to soak back into the ground before reaching open water. The garden is planted with native vegetation that can withstand both wet and dry conditions.
  • The Rain Garden is an educational demonstration project with displays explaining how rain gardens are designed, and steps homeowners can take to improve stormwater retention on their properties. As a result of climate change, Northern New England is projected to have more major, longer-lasting storms. To reduce the severity of future flooding, homeowners can retain rainwater using swales, retention ponds, rain gardens and other solutions described in New Hampshire’s  State Guide to Homeowner Stormwater Management Solutions.
  • Thanks also to Wes Tarr and the Town Road Crew for  creating this Rain Garden for the town. 

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