Clifton’s Hemlock Park gets national recognition as home of oldest trees in Fairfax County

An approximately 20-acre portion of Hemlock Overlook Regional Park is being inducted into the national Old Growth Forest Network (photo by José Fernández for NOVA Parks)

About 20 acres of eastern hemlock trees rooted to the Bull Run River banks in Clifton will be formally recognized tomorrow (Tuesday) as likely the oldest trees in Fairfax County.

Believed to be at least 250 years old, the trees in Hemlock Overlook Regional Park are the first stand in the county and only the second in Northern Virginia to join the Old Growth Forest Network, a national nonprofit that aims to identify and protect the oldest known forests in every county in the U.S.

The Northern Virginia Regional Park Authority (NOVA Parks) will celebrate the milestone at 2:30 p.m. tomorrow by unveiling a permanent sign explaining the forest’s significance.

The ceremony will also include an early Earth Day commemoration. Fairfax County Board of Supervisors Chairman Jeffrey McKay, Springfield District Supervisor Pat Herrity, and other local officials are expected to attend.

“We want the people hiking along the trail to not just have a great experience hiking…but also learn something about the interesting and unique environment that they’re in,” NOVA Parks Executive Director Paul Gilbert said. “…This is a very unusual thing to have an old growth forest in an area that has been heavily forested and developed for over 150 years, and it certainly fits with the mission of NOVA Parks to conserve these areas and to educate the public about these areas.”

With its induction, Hemlock Overlook follows in the footsteps of Arlington’s Glencarlyn Park, which had a 24-acre portion added to the Old Growth Forest Network in 2o15.

Founded in 2012 by ecologist and author Joan Maloof, the network has grown to over 190 forests across 32 states. All included forests have protections in place against logging and are publicly accessible, though there are separate designations for private and smaller community forests.

Gilbert says NOVA Parks was aware that Hemlock Overlook had a “very old forest area,” but the Old Growth Forest Network identified it independently and then reached out to the authority.

The nonprofit works with county coordinators in local communities to help it identify potential old growth forests that are publicly accessible, according to Brian Kane, the OGFN’s Mid-Atlantic regional manager and community outreach manager.

The organization had gotten seven or eight nominations in Fairfax County, including for some stands along George Washington Memorial Parkway, but the Hemlock Overlook trees ultimately stood out.

“It’s really kind of remarkable this is standing there in busy Fairfax County,” Kane said. “…We’re absolutely thrilled this is happening.”

The eastern hemlock is an evergreen that thrives in the shade and on steep terrain, but a shallow root system leaves it vulnerable to wildfires, drought and the wind, according to the National Park Service.

The Hemlock Overlook stand’s remoteness — it can still only be reached with a 20 to 25-minute walk — probably saved it from being cut down, even as much of the area’s forests were eliminated, first for farming and then for development, Gilbert says.

“[Old growth forests are] really, really rare, particularly in areas that were urbanized,” he told FFXnow. “But even before urbanization, if you look at pictures from the Civil War period…there were almost no trees. They cleared everything for agriculture, and you could just see it’s just flat land everywhere. So, we have a lot more trees in Northern Virginia today than we did 150 years ago.”

According to a joint press release from NOVA Parks and the OGFN, less than 1% of the eastern U.S.’ original forests are thought to still be standing.

These trees offer exceptional ecological value, such as providing valuable canopy layers that shelter hundreds of species of birds, insects, and mammals. Old-growth trees also retain more pollution-causing carbon and nitrogen than younger trees, and slow growing hemlocks are especially good at absorbing carbon from the air and holding stream banks in place.

In addition to signifying its “old growth” status, the sign installed at the park tomorrow will mark the trees as an example of a mature forest at the end of the forest succession cycle, which tracks how ecosystems evolve as environmental conditions change.

As part of the new, five-year strategic plan it adopted last summer, NOVA Parks will add explanatory signs at eight of its parks in different stages of succession, with Bull Run and Fountainhead joining Hemlock in Fairfax County.

Other markers in the agency’s environmental interpretive series will focus on protected rare and endangered species, the wingspans of birds of prey, and dragonflies, according to Gilbert.

The strategic plan also laid out the agency’s vision for future park facilities, including an expansion of its “dual trail” design for the Washington & Old Dominion Trail into Fairfax County.