The Accotink Gorge
The Accotink Gorge, an imperiled biological gem and the call to action to defend it.
October 10, 2017, Accotink Gorge Wisteria Workday
The day was rather warm, with temperatures in the 80's, but the humidity was remarkably high and uncomfortable. Still we persevered. Four volunteers did the vine cutting, while three professionals of SOLitude Lake Management provided the support of qualified herbicide application.
The cutters moved from vine to vine, lopping and sawing, while the applicators followed behind, giving an immediate squirt of glyphosate to each fresh stump. Over a period of weeks, the herbicide will be drawn down deep into the roots, permanently ending each wisteria vine's hostile attack on the flora of the gorge. Vines ranged in size from mere seedlings to well-established monsters four and five inches in diameter, climbing into the canopy.
We worked in two groups. One group focused its efforts on "The Headland", the place here where Accotink Creek is joined by a small tributary from the north that has been identified as the most in danger of losing its uncommon flora to the advancing vines. The second group moved across the creek on a precarious log to eradicate the larger vines there that might spread their seeds to the Headland. Only one voluneer fell in, and only up to the knee.
Anti-wisteria team after their afternoon of vine cutting
August, 2017 - Wisteria management begins in the transmission right-of-way
Movement against wisteria in the Accotink Gorge by Dominion Energy, which has commenced mowing beneath the power lines, to be followed by future targeted spraying of resprouting wisteria. Mowing is not an adequate description for this work, as the machines grind everything to dust right down to the ground. All the native perennials may be expected to readily rebound by next spring.
Dominion Energy machines at work in the Accotink Gorge
December 2016 - Encroaching development or preservation for the Accotink Gorge?
A 10.4 parcel of private land including a portion of the lower end of the gorge is on the market. How great it would be to find a way to preserve this land, which borders park lands and includes a stretch of the creek. Any angels with deep pockets out there? Real estate listing information
Our October 15, 2016 Wisteria Workday:
A small band of FACC volunteers, taking on invasive Chinese wisteria vines in a targeted area, and getting a lot done! Wisteria poses a significant threat to the existing native forests and meadows in Accotink Gorge - its abundant growth smothers and stifles native plants, competing for resources and reducing available habitat.
Wisteria vines spiral up tree trunks, burdening trees. Over time the vines constrict around the growing trunks, compromising the trees’ health, and leaving obvious grooves when removed. In many cases the vines look like taut ropes anchoring the tree to the ground, and can be several inches thick - too wide for loppers to cut. But we also had pruning saws!
We clipped as many vertical vines as we could, reducing the burden on the trees and providing a temporary setback to the wisteria's ambitions of dominance. However it is nearly impossible to completely eradicate wisteria this way - there are long networks of roots stretched across the forest floor that will continue producing vines, requiring a professional invasive management strategy.
FACC is leading invasive workdays and awareness walks in the Accotink Gorge in order to build public awareness and engagement on this important issue, while building our capacity and effectiveness as a team of volunteers - this is a very ambitious project for us, and the scale of the challenge can be overwhelming. But as shown this weekend, a few people can make a meaningful difference with a few hours work!
We are working on an agreement with the Fairfax County Park Authority that will allow us to engage more directly on this issue, and we appreciate their willingness to work with us. We also welcome partners and volunteers to work with us on this campaign to Save Accotink Gorge!
Our April 26th, 2016 Wisteria Workday:
A small scale trial run against Chinese wisteria took place on the "Headland", the part of the gorge identified as the best place to halt the advance of the alien vines before they overtake this zone especially rich in uncommon native plant species.
The steep slope here presents an obstacle to effective action. Volunteers found it challenging to maintain their footing while simultaneously accessing the vines. The perils included avoiding treading on the very plant species we are trying to protect, and sliding downhill, leaving areas bared to future erosion. It seems only the most cautious and concerned volunteers should be selected to work this particular spot.
Two methods of control were employed - pulling up small seedlings by the root and clipping off established vines near the ground. Future efforts, if they are to be effective long-term, will need to incorporate licensed herbicide application to stumps.
Our October 24th, 2015 Wisteria Workday: Something of a non-event, with no cutting (due to permitting delays), no naturalist guides (due to health issues), and few of the most exceptional native plants at their seasonal best.
Nonetheless, a number of stalwart volunteers did show up and went on three treks into the gorge - to the critical highland, to the meadow habitat under the power lines, and upstream to the "Great Falls" of the Accotink. We were impressed, however, by a small display of Purple passionflower fruits. It unfortunately paled in comparison to the uncountable thousands of Chinese wisteria seedpods to be seen.
Unable to attack the Wisteria, our volunteers went into cleanup mode, removing bag after bag of thoughtlessly discarded trash. Among the trash was a fresh illegal tire dump, which we labored to haul up the slopes out of the gorge.
July 7, 2015 - Concerned naturalist guides survey of the exceptional flora of the Accotink Gorge and issues an urgent call to action:
What is the Accotink Gorge?The Accotink Gorge is truly one of the most biodiverse locations I have ever had the privilege of exploring, especially given its small size and proximity to development. However, if urgent action to remove Wisteria sinensis (Chinese wisteria) vines which are rapidly killing its canopy trees is not taken soon, all of this will be irrevocably lost. Many beautiful native wildflowers are currently in bloom and the area is teeming with pollinators and birds. It is not too late to save this oasis, but it will be soon.
In the interest of preserving the unique biodiversity of the site, despite the fact that it is the fertile floodplain forest that is currently most seriously infested, the high dry rocky oak hickory forest, which is just starting to be invaded, is where the Wisteria sinensis removal should begin, as it contains the most uncommon species, and unlike the floodplain habitat, which has evolved in a state of continual disturbance, and should regenerate well, the ancient plant communities on the higher slopes, and the fragile soils which support them, once lost, will be lost forever.
In Accotink Stream Valley Park, in the southern portion of Accotink Gorge, exists one of the more diverse examples of oak hickory heath forest in the entire Fairfax County park system, where native trees and shrubs coexist with native grasses such as Danthonia spicata (Poverty grass), Piptochaetium avenaceum (Blackseed needlegrass), and Melica mutica (Twoflower melicgrass), as well as flowering herbaceous species such as Clitoria mariana (Butterfly pea), Aureolaria virginica (Downy false foxglove), Silene caroliniana (Wild pink), Symphyotrichum patens (Late purple aster), and Asclepias variegate (Variegated milkweed). There are also some extremely steep slopes in the oak hickory forest, with particularly acidic soil, where the Wisteria has been unable to invade, but the understory in these sections consists largely of Kalmia latifolia (Mountain laurel), and is not particularly species diverse.
Throughout Accotink Gorge, the priority should be saving the canopy trees that are still salvageable, starting at the higher elevations, once that is done, the understory can be dealt with. Based on the spring ephemerals that I observed before the Wisteria leafed out, the native floodplain forest understory vegetation has not died out yet, it is merely being suppressed by the Wisteria growing on top of it, and it should regenerate fast and well once the Wisteria is removed. The meadow created by the powerline cut which bisects this area is also quite biodiverse, providing habitat for sun loving native species including milkweeds and many grasses, whose populations have declined in natural areas due to fire suppression, however it is a distant last on the priority list for Wisteria removal. There are invasive species other than Wisteria in Accotink Gorge, but it is the Wisteria that is killing the canopy trees, and until that is dealt with, worrying about anything else is just a distraction.
I fell in love with this place as soon as I set foot there, and I hope to share this experience with other people who might be able to make a difference to save it. Despite seeing how fast the Wisteria has advanced over the course of just one year, and the fact that it has begun to actually topple over canopy trees, creating a nearly impenetrable thicket in some areas, I truly believe that it is not too late. The only plants that should be removed from this place are invasive species. I have come upon evidence of the poaching of large colonies of Epigaea repens (Ground laurel) from this location, and I want to make it very clear to anyone who may be misguided on the issue that removing native plants from an embattled natural area such as this is not a "rescue". Please leave all the native plants where they are so that they can revegetate the areas that will be disturbed in the process of Wisteria removal. Many of the species present in this very special area are only present in very small populations, for instance, there is only one Ionactis linariifolia (Flax-leaf ankle-aster) so, at least until the Wisteria has been removed, and populations of these native species have had a chance to recover, it is not even appropriate to collect a voucher specimen.
If you know anyone who would be able to help organize invasives removal work, please forward this to them and bring them into the discussion. It is my hope that this event will catalyze the community to come together and save this very special place for future generations.
Fritz Flohr Reynolds - July 7, 2015
Great Falls of the Accotink, at the confluence with Field Lark Branch
Native Flora Species observed so far in the Accotink Gorge, with photolinks: