Wilburdale Park has a playground, playing fields, and a lawn, but most of it is forest. As is typical of small parks in the DC region, Wilburdale’s forest is heavily infested with invasive alien plants. This photo was taken just before we began working in this part of the park; the vegetation at the base of the trees, as well as nearly all the vines, consists of invasive alien species. (May 2003)

The forest edge behind the basketball court is covered with Oriental bittersweet (Celastrus orbiculatus), an invasive alien vine from east Asia. This type of infestation is sometimes called an "invasive curtain." (June 2002)

Wilburdale encloses about 2,200 feet of Backlick Run. The stream emerges from the ground about 2,000 feet upstream from the park boundary, but even in its upstream reaches, Backlick Run is destabilized from heavy stormwater runoff. The vegetation along the bank here is mostly multiflora rose (Rosa multiflora), a thorny, invasive alien shrub from east Asia. (May 2003)

This photo was taken several hundred feet upstream from the previous one. The unstable stream channel has badly undercut these two northern red oaks (Quercus rubra). We are trying to save them but the prognosis is uncertain, to say the least. (May 2003)

A close-up shot of the forest edge. The invasive alien multiflora rose has blocked succession in this clearing—tree seedlings can’t come up through it—and several invasive vine species are weighting the trees, making them more susceptible to wind-throw. Without intervention, some of the trees will likely fall, and the invasive thicket will expand. (May 2003)

Within the forest, the invasives have come to dominate much of the shrub layer. Here you can see a forest understory thicket of European privet (Ligustrum vulgare), a common hedge plant that is invading natural areas. (June 2003)

The native ground- and shrub-layers are threatened by the invasives, but many native species are still present at Wilburdale. Here you can see the native forest herb mayapple (Podophyllum peltatum), the little plant with the umbrella-like leaves, growing amidst the multiflora rose. (May 2003)

A patch of wild ginger (Asarum canadense), another native herb growing on Wilburdale’s forest floor. (May 2003)

A sunlit patch of native trout lily (Erythronium americanum). In the DC area, trout lily is common along forested streams. Like many other forest herbs, it emerges and blooms before the canopy has fully leafed out, so that it can take advantage of the sunlight that reaches the forest floor during early spring. By the time the forest is fully in leaf, herbs like trout lily have done most of their growing for the year. (April 2004)

A stand of Jack-in-the-pulpit (Arisaema triphyllum)—the taller plants with the triple-lobed leaves. (This photo was taken after the year’s flowers—the “pulpits”—had gone.) The plants growing underneath are Oriental bittersweet. If this patch of forest floor were left unmanaged, the bittersweet would almost certainly suppress the Jack-in-the-pulpit. (July 2003)

Yet another native herb: skunk cabbage (Symplocarpus foetidus), a denizen of wet, shady spots. Skunk cabbage gets its common name from its resemblance to cabbage. (Okay, here’s the other part: it’s called “skunk” because of how it smells when its leaves are damaged.) (April 2004)

Wilburdale also boasts some big, handsome trees, like this tulip poplar (Liriodendron tulipifera). In addition to tulip, the park’s canopy includes American beech, several species of hickory and oak, green ash, American elm, and red maple. The canopy is not especially distinctive but it’s certainly well worth conserving. (June 2003)

A good first step in managing a forest overwhelmed by invasive plants is to cut away the vines growing up the trees, as these volunteers are doing. Cutting the vines helps to stabilize the canopy; unencumbered trees are less likely to weaken and fall over. (May 2003)

A patch of Wilburdale’s forest after the vines have been cut. The trees look as if they have had very bad haircuts! In circumstances this extreme, we often end up cutting native vines as well as alien ones. That’s partly because the growth is so dense that it’s difficult to see what’s what, but also because the alien vines often grow up the native ones. Of course, it’s too bad to lose the native grapes and so on, but at this stage, it’s crucial to deny the aliens access to the canopy. We let the natives grow back. (May 2003)

The big tulip poplar in the center of the picture is encumbered with a long skein of cut Oriental bittersweet. It’s not necessary to pull the vines out of the trees. They’ll eventually just fall off on their own. (July 2003)

A more recent photo of the same tree, now unencumbered. In the foreground, you can see the beginning of a stream buffer planting. (May 2008)

At Wilburdale, the Oriental bittersweet is very well established. Some of the vines, like this one, are as thick as small trees. (June 2003)

There’s a lot of work to do in the groundlayer as well. Here, a member of Brownie Troop 1091 uproots garlic mustard (Alliaria petiolata), an invasive alien herb from northern Europe. (May 2005)

Troop 1091 reassembles after routing vast quantities of garlic mustard. (May 2005)

The spoils. We prefer to compost our slash but this batch of garlic mustard might already have started to set seed, and we didn’t want to risk contaminating the county’s compost with viable seed, so we bagged the plants. (May 2005)

We do other things at Wilburdale besides controlling invasives. In 2004, for example, we celebrated World Water Monitoring Day at Wilburdale, along with the EPA Office of Water and the Northern Virginia Soil and Water Conservation District (SWCD). The event was organized by SWCD’s Joanna Cornell, who also conducted an ecological water-monitoring event in the stream. Joanna showed us how to find and identify the creatures living in the stream, and what their presence indicates about the stream’s condition. The diagnosis: Not terminal, but not especially encouraging either. (October 2004)

Also in 2004, SWCD’s Willie Woode conducted an in-depth appraisal of the physical condition of the Wilburdale reach of Backlick Run. Again, the diagnosis was not particularly encouraging. The stream channel is eroding in many places, and depositing large quantities of sediment in other places. The trees along the bank are at risk, and the sediment is lowering water quality. (July 2004)

Many of our ordinary working days at Wilburdale—as elsewhere—include a picnic. (May 2005)

In 2004, we decided to launch a more intensive invasives-control project in this part of the park. Before we started, the area consisted of a thicket dominated by multiflora rose (in the foreground), and some badly infested forest (background). This was one of the most densely infested parts of the park. (May 2003)

Another view of the same area, showing the badly encumbered trees. The invasives in the foreground have interrupted succession: the forest cannot return to this area on its own because tree seedlings cannot grow up through the thicket. (May 2003)

There was nothing worth saving in the thicket, so we asked the Fairfax County Park Authority to “brush-hog” that area, thereby removing virtually all the above-ground growth. In exchange, we agreed to replant, as our volunteers are doing here. The stakes mark where seedlings have been installed. (July 2004)

Some of the trees in that initial planting have grown to sapling size, or larger. Here is Lisa Bright, our Executive Director, with one of our green ash (Fraxinus pennsylvanica) seedlings a year after planting. It’s even bigger now! (May 2005)

Although the brush-hogging removed all their top growth, many of the invasives were rooted extensively in the area and we knew that it would probably take years to kill the roots. (Application of herbicide here was not feasible.) We accelerated this process by covering some areas temporarily with heavy black plastic. The plastic denied the resprouting plants light; it also “cooked” the soil under the summer sun, thereby helping to kill roots at the soil surface. (July 2005)

After the plastic was removed, we applied biodegradable erosion-control blanket and organized another planting. In our experience, it is better to manage areas like this with a series of plantings, rather than trying to do everything at one go. This incremental approach makes it easier to adapt to changes on site—resprouting invasives, effects of flood and drought, heavy deer browsing, wayward adolescents, and other stresses natural or otherwise. Here, volunteer Stephen Lewis prepares the site by setting out plants. (October 2005)

This planting was done in partnership with Homestretch, a northern Virginia nonprofit that provides transitional housing services to formerly homeless people. The planting offered our Homestretch volunteers a chance to work together, socialize, and learn a little about our local parks. (October 2005)

Volunteer-based restoration projects are good for people too. Such projects can help build community. (October 2005)

These projects also help recruit people into the craft of planting. The woman in the blue hat is Joan Makurat, a very experienced planter; here she shows a Homestretch volunteer how to put in a seedling. (October 2005)

A sewer line runs under a portion of the planting. It’s generally not good practice to install trees in sewer easements because they might be dug up if the pipe needs attention. We dealt with this problem by planting the easement with native herbs (nonwoody plants), like this woodland sunflower (Helianthus strumosus). Such plants should spread, so even if the easement is excavated, there’s a good chance that some woodland sunflowers would survive the excavation to repopulate the area. (October 2005)

A view of the site after the Homestretch planting. You can see that one area is still being treated with black plastic. Those pink tubes are tree shelters; they protect the seedlings. (October 2005)

This is why we use tree shelters! Many parks in the DC-area are intensively browsed by deer. Unfortunately, heavy deer browsing can exacerbate the invasives problem. That’s because the invasive species that deer don’t like—and there are many—get more growing room when deer eat large numbers of other plants. (September 2005)

A view of the site in 2006. The volunteers in the background are checking on the seedlings, fixing the tree shelters, and cutting back invasives. (October 2006)

Since 2006, the GW Community High School, in the Annandale section of Fairfax County, has been working with us to maintain the planting. Here, a GW student fixes a tree shelter. (October 2006)

GW Students extend the planting along Backlick Run. (October 2006)

The planting also benefited from the help of students from the Flint Hill Elementary School in Vienna, Virginia. Here, some Flint Hill students are working along the edge of the site, removing the invasive alien vine, Japanese wisteria (Wisteria floribunda). (September 2005)

This was a stubborn vine—but we’re pleased to report that the student prevailed. (September 2005)

Our Flint Hill crew after a successful day of wisteria-pulling. (September 2005)

Our hardy crew of GW School volunteers takes on another patch of multiflora rose. They are cutting the top-growth only—we are trying limit disturbance to the soil in this frequently-flooded area. (March 2008)

GW volunteers celebrate the day’s trophy pile. The woman in the red rain jacket is Alexa Warden, an instructor at GW, one of the school’s founders, and now a key player in our struggle with Wilburdale’s invasives. (March 2008)

Lisa Williams, a biology teacher at Northern Virginia Community College (“NOVA,” as it’s known locally), and Tommy Ventre, our Tree Bank Program Manager, contemplate the Wilds of Wilburdale. Lisa’s 2008 NOVA botany class is volunteering at Wilburdale. (March 2008)

This area, adjoining our current forest restoration area, is one of our restoration targets for 2008. It’s basically a multiflora rose thicket, with a sparse, vine-encumbered tree canopy. (That probably sounds pretty familiar by now!) (March 2008)

This is a portion of our other target area at Wilburdale for 2008. This area has a fuller canopy but the understory is almost entirely composed of European privet. (March 2008)

Our spring 2008 agenda at Wilburdale got a huge boost from a Virginia Department of Forestry Water Quality Improvement Fund grant, and from field work donated by Professor Lisa Williams’s botany class at Northern Virginia Community College (known affectionately as “NOVA” in these parts). Here, Earth Sangha Executive Director Lisa Bright (in green jacket) conducts an orientation for the NOVA students. That big concrete trough on the right is a stormwater ditch; it carries run-off into Backlick Run, the stream that winds through this park. (April 2008)

As part of our spring initiative, the Fairfax County Park Authority, which owns Wilburdale Park, invited us to plant a strip of native trees and shrubs along the edge of the lawn that borders part of Backlick Run. Such stream-buffer plantings help stabilize streams and improve water quality. To make our planting more stable, we started by controlling the invasive alien vegetation already growing along the stream bank. (April 2008)

The most troublesome invasives along this part of the bank were multiflora rose (Rosa multiflora) and Oriental bittersweet (Celastrus orbiculatus). (April 2008)

The NOVA students did a great job knocking down the invasives, as you can see. The objective here wasn’t to eliminate the invasives entirely―that would have taken far too much work―but just to suppress them enough so that they wouldn’t interfere with our planting. In later years, as the planting grows, we’ll continue to push the invasives back, as we are doing in other areas of the park. (April 2008)

Our spring agenda included invasives control in other areas of Wilburdale as well. A major spring objective was to expand the half-acre flood-plain planting shown here. This planting also borders Backlick Run; we started work on it in 2005. (Those “tree tubes” and screens protect the seedlings against deer.) (April 2008)

Most of this planting was an invasive thicket before we started, and the invasives had suppressed the growth of native tree seedlings. The area is still badly infested, as you can see here. It’s pretty obvious where the planting ends and the multiflora rose begins! (April 2008)

Our plan was to extend the floodplain planting by at least half an acre. For the first step, we turned to the Fairfax County Park Authority, which donated a crew to “brush-hog” the invasive thicket that covered our target area. Here is what the site looked like after the FCPA crew finished. In this picture, we are setting out the first batch of plants for installation. The crew was able to clear a little over an acre of invasives―a major advance! In the far background, you can see the original planting. (April 2008)

After the brush-hogging, we cut the invasive vines that were growing up the trees. As in the original area, there aren’t many trees here because the invasives have suppressed forest growth. (April 2008)

The vines can burden the trees quite heavily. The burden on this tree consists mostly of English ivy (Hedera helix), Oriental bittersweet, and Japanese wisteria (Wisteria floribunda). The vines compete with the trees for light and nutrient, and their weight makes the trees more likely to fall during storms. (April 2008)

Once the vines have been cut and the invasive shrubs suppressed, we can start planting. We planted a wide range of native, moist-soil trees, shrubs, and herbaceous plants, all grown at our Wild Plant Nursery. (April 2008)

For the long-term health of the site, it’s important to establish a wide variety of tree species. We cannot rely on natural regeneration alone in a situation like this, because the surrounding stands are too badly degraded, and the invasives still have a very strong grip on this site. (April 2008)

All those little seedlings have been planted into some very extensive invasive root masses. The invasives will resprout―copiously―for years. Regular control will be essential for maintaining this planting. (April 2008)

Our old floodplain planting has now been extended by a little over an acre. But, as with that original planting, we expect to tend this little patch of resurgent forest for many years, mainly to fend off the invasives, but also to replace the seedlings that die, and to enrich the planting with other species as opportunity permits. We believe that long-term engagement with a site is generally the best guarantor of success. (April 2008)

We also believe that lunch is important! A group photo before one of our work-day picnics. (April 2008)

Back to the buffer strip project on the Wilburdale lawn. It’s time to plant there too. Here, Tree Bank Project Manager Tommy Ventre shows the NOVA students how to extract a seedling from a pot. (We don’t assume much in the way of prior knowledge!) (April 2008)

As with the other Wilburdale plantings, the planting stock for this buffer strip came from our Wild Plant Nursery. Here, the plants have been dropped in place along the buffer. (April 2008)

The buffer goes in. Note that this section of stream bank has been “armored” (lined with stone), to prevent it from eroding. The opposite bank is not armored. Armoring is sometimes necessary but it does tend exacerbate erosion downstream. (April 2008)

The NOVA students did an excellent job with this planting. (April 2008)

This site looks more forgiving than it is. Planting into bulldozer-compacted turf can be tough, as these two students have apparently found. But they prevailed―the seedling went in! (April 2008)

The plants are in and the tree shelters have been installed. That’s several hundred more feet of buffer for Cameron Run! (April 2008)

At this point, the buffer planting is only 10 to 15 feet wide. We hope to widen it in subsequent years, but the lawn is an important meeting place for the neighborhood, so we’ll just have to see how local residents feel about that. Our present planting may narrow, but it sure is dense! In terms of buffering effect, the density may compensate somewhat for the narrowness. (April 2008)

A group photo of our NOVA collaborators, along with the Sangha’s Tommy Ventre, on the far left. NOVA professor Lisa Williams is to the left of the picnic table, in the purple shirt. (April 2008)

Students from the GW Community school were another very important group of collaborators at Wilburdale this spring. GW Community has been working with us at Wilburdale since 2006. Here, the Sangha’s Tommy Ventre (third from left) orients a group of GW students for a forest enrichment planting. (April 2008)

Enrichment plantings are an important part of our work at Wilburdale. They help us maintain our large-scale plantings; they help us displace invasives; and, increasingly, they help us cope with erosion from stormwater runoff. (April 2008)

Wilburdale’s forest owes a growing debt to GW students. We hope that this effort will benefit the students as well, by giving them the opportunity to create a meaningful connection with a local natural area. (April 2008)

Our Wilburdale agenda for spring 2008 also included a tour for local National Wildlife Federation Habitat Steward volunteers. Here, Chris Bright, the Sangha’s President, talks to the stewards about the condition of Backlick Run. That’s Chris with his back to the stream. (May 2008)

Lisa leads the stewards into the floodplain forest restoration area, and describes our struggle against the invasives. (May 2008)

Of course, no tour is complete without a little hands-on effort! Here the stewards try their hands at pulling European privet (Ligustrum vulgare), an invasive plant that dominates the shrub layer of portions of Wilburdale’s forest. (May 2008)

The haul of uprooted privet. Bit by bit, thanks to efforts like these, native forest is reemerging at Wilburdale. (May 2008)

Winter is a good time to go after a lot of woody invasives. The lack of foliage makes it easy to see what you’re doing. These volunteers are clearing a thicket of European privet. (March 2009)

A successful bout of invasives control! (March 2009)

Our privet-control efforts yielded a substantial amount of slash―evidence that our volunteers are really making a difference in the park’s forest. (March 2009)

The “tree tubes,” which protect tree seedlings from deer, mark our planting on the lawn side of the park. These trees were planted in the spring of 2008. The groundlayer, unfortunately, is almost entirely Oriental bittersweet (Celastrus orbiculatus), a very invasive alien vine. If we don’t deal with it, it will overwhelm the planting. (June 2009)

We dispatched a couple of our seasoned “Weeding Divas”―Valerie and Melissa―to deal with the bittersweet. (June 2009)

This is our stream-buffer planting at one year. The trees are in good shape, but the planting is threatened by Oriental bittersweet and another aggressive alien vine, porcelainberry (Ampelopsis brevipedunculata). There’s also some native grape in there, but the grape is no match for the alien vines. (June 2009)

A closer look at the buffer planting. Several dogwoods are rising above their tree protectors. And the “no mow” management seems to be working: dense growth of the native jewelweed (Impatiens capensis) seems to be outcompeting the invasive alien grass, Japanese stiltgrass (Microstegium vimineum). Believe it or not, invasives control can be kind of a balancing act. Sometimes relatively light management can tip the balance back in favor of the native plant community. (June 2009)

A year later, we’re still at it. Along the stream bank, a volunteer carefully lops away Oriental bittersweet. This vine’s root system is extensive, and at least for now, we think that it’s best left in place, to prevent erosion of the bank. But cutting back the bittersweet top growth will prevent it from taking over our planting. (May 2010)

There’s a dogwood in there somewhere! Two volunteers from the local Art of Living Chapter cut alien vines off a dogwood sapling. (May 2010)

Two high school students bag invasives in a part of the forest that hadn’t seen any control for an entire year. They were pulling European privet, Oriental bittersweet, and the invasive alien herb, garlic mustard (Alliaria petiolata). But by local standards, this patch of forest wasn’t in bad shape. We may be making some progress in there. Unfortunately, however, we lost the better part of one of our plantings, as you can see from the tree tubes stacked behind the students. Too bad―but not every planting succeeds. That’s one of the reasons why we have our Wild Plant Nursery; we can always replant! (June 2010).