Volunteer group rebuilds the canopy in the Wissahickon, one tree at a time


I don’t think i would have noticed that the patch of forest off Livesey Lane had been restored if Steve Jones, president of Wissahickon Restoration Volunteers (WRV), hadn’t told me.

I visited the area on a humid morning in late May. The canopy was complete, shading out the sun completely. I heard the usual forest birds around me: the flute-like singing of a wood thrush, scolding chickadees. The trees, though, mostly red maples and tulip trees, were small as forest trees go, with trunks about 8 to 12 inches in diameter.

WRV planted those trees starting about 20 years ago, according to Jones, when the ground had been covered by exotic plants, making it impossible for trees to grow. Indeed, further up Livesey Lane, I passed an impenetrable thicket of Japanese knotweed, this spring’s shoots already 10 feet tall, that could have served as the “before” photo for the restored forest downhill.

Volunteer with shovel near tree sapling, in forest
Photography by Rachael Warriner

WRV started restoring forests in 1997, planting native trees and shrubs while removing exotic, invasive weeds. That year Jones spotted a volunteer recruiting brochure for the new organization on a bulletin board at the Andorra Free Library. “The WRV was founded by Joe Dlugach,” said Jones, “He asked me what kind of skills I had, and I said I didn’t have any skills; I’m an English teacher. So I started editing the newsletter for the group, and I learned more about what ecological restoration is.”

Now, the organization is taking advantage of more than two decades of work to assess what works and what doesn’t. Jones says the group has located approximately 4,000 stems, trees or shrubs that WRV planted between 1997 and 2019 and is trying to get a handle on which species are surviving at which sites and how they are growing.

“It tells us what planting regime is giving us the best bang for our buck,” says Jones. For example, early results of their analysis show that oak trees are particularly slow to grow, while red maples and tulip trees shoot up quickly and form a canopy that shades out the exotic plants.


“I would expect it to take a decade or so for the trees to be large enough to shade out the knotweed,” says Bill Keyes, who lives in the Blue Bell Hill neighborhood on the edge of the Wissahickon, where WRV started working with neighbors to plant trees and cut back Japanese knotweed four years ago. Today the saplings, protected by black plastic deer guards, stand surrounded by Japanese knotweed that are only a foot or two tall, hacked back by Keyes and his neighbors. Keyes says they also protect the young trees from fast-growing vines that could easily overwhelm them.

Planting trees during the COVID-19 pandemic this spring has been a little tricky to organize, says Jones, given the need to stay 6 feet apart. Ordinarily, a tree planting involves several volunteers working together to dig holes and plant multiple trees in one event.

“So we came up with a program called One Tree at a Time,” explains Jones. “One of our leaders goes to established sites and stages tools and plants at the sites. Later, another one of our leaders comes along and installs the trees by himself or herself and then does some suppression of exotic invasives in the area.”

Volunteer Chris Richter describes his role in a One Tree at a Time planting.

“I went out with my daughter near Historic Rittenhouse town,” says Richter. “We cut a patch of weeds out and planted a tree there.”

This summer the WRV will be launching an oak experiment, planting the stubbornly slow-growing trees in pairs. One of each pair will be planted directly into the forest soil, as WRV has been doing it for more than 20 years. The other will be planted in a hole including biochar, a charcoal soil additive, as well as fungi that could benefit the growing trees by forming mycorrhizal networks, according to Jones.

Oaks, like most plants, grow best in symbiosis with soil fungi that penetrate the tree roots, helping them take up soil nutrients. The question is whether this inoculation at planting will make up for poor soil at the sites.

It’s a waiting game, but in another 20 years, WRV should know the answer.

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