By Abby Marino
In the heart of Manhasset lies a 400-acre piece of land not often seen by the public, yet teeming with biodiversity and wildlife. The Greentree Foundation, founded in 1982, stewards this land in its commitment to peace, philanthropy, and sustainability. Among their programs for climate change mitigation and water protection, they also have staff dedicated to land management and grassland restoration; that includes managing invasive species with a unique canopy-gap strategy.
Conservation at Greentree begins with knowing the species. “We believe at our core,” says Stephane Perreault, Naturalist, “that in order to properly manage the forest and the land, we need to know what plants and animals are there.” With help from the New York Natural Heritage Program, they were able to characterize the imperiled communities of oak-tulip tree forests, red-maple sweetgum swamps, and successional hardwoods that inhabit the property. “It was very rewarding for us to understand that 80% of the forest at Greentree actually are imperiled forest communities within New York State.” says Stephane, “We were already committed to our invasive removal program, but this was kind of a shot in the arm [that shows that] we’re doing the right thing here.” This knowledge gave them the focus to protect these imperiled areas from invasive species encroachment.
In Greentree’s forests 95% of the canopy are native plants, which see this as a great benefit for native tree regeneration. However Norway maple (Acer platanoides) in the subcanopy poses a threat, as canopy gaps can allow the invasive tree to become increasingly prevalent. In response, Greentree focuses on “forest gap management”, meaning they prioritize removing invasive species specifically in canopy gaps to ensure the next generation of canopy trees are native. “These prioritization strategies keep [our] sanity,” says Stephane.
Along with winged euonymus (Euonymus alatus), they also face other invasive shrubs and vines in the understory, including multiflora rose (Rosa multiflora), linden viburnum (Viburnum diltatum), invasive ivy (Hedera helix), vine honeysuckle (Lonicera japonica), and bittersweet (Celastrus orbiculatus).
With machinery, hand tools, and limited herbicide use, they are able to conduct targeted invasive species management in marked canopy gaps. In late summer, a skid steer with a brush hog attachment helps clear invaded woodland edges. This helps with access, but with the roots left behind, Stephane warns that the vegetation will come back. His other favorite hand tools for shrubs include the root slayer and honeysuckle popper, as he works with two other crew members to remove invasive shrubs from November through March. Any trees that are too big for pulling, they mark for later removal. They also stay on top of the data, marking all canopy gaps in GIS and tracking their efforts in transformation (the first effort of work at a site) vs. maintenance (all follow-up visits to the site).
They are delighted to find native plant species regenerating after invasive plant removal in some areas, including nodding trillium (Trillium cernuum).
Apart from land management, they track other invasive pests on their property. Since 2021, they have monitored beech leaf disease (Litylenchus crenatae-mccannii), measuring the leaf and canopy characteristics in the field. With beech comprising 11% of the canopy and 28% of the subcanopy at Greentree, they note the increasing impact of the disease on mature trees and saplings. They also monitor for oak wilt (Bretziella fagacearum), as well as spotted lanternfly (Lycorma delicatula), spongy moth (Lymantria dispar), and viburnum leaf beetle (Pyrrhalta viburni).
The Greentree Foundation and Seatuck Environmental Association are looking forward to hosting their Teachers Ecology Workshop coming up in July 2024, which promises to give hands-on experience to teachers to incorporate nature into school curricula.
LIISMA thanks Stephane for sharing his knowledge and management techniques at our Partners Meeting, and to the Greentree Foundation for their work in conservation and invasive species management.
Watch Stephane’s presentation here.
