Women shook mulberries from a tree with an umbrella flipped inside out. An opera singer practiced his scales in the woods. Campers had arranged chairs and cooking supplies around a sapling.
At Kissena park, a field of mugwort, a weed that takes over waste places and irritates the skin, had become a growing forest. Danica Doroski, MFS ’17, went to the park to measure the trees, but she also saw connections growing between the forest and people.
Six years ago The Million Trees NYC Initiative planted her study site, the former field, with young saplings. The whole project, which planted one million trees in New York over ten years, cost 400 million dollars.
Such an expensive endeavor, Danica pointed out, needs follow-up. Managers need to know which plantings took root, and which failed. In the course of her master’s research in Kissena Park, Danica asked, which trees dropped seeds that established and grew? Though young, the forest is already changing.
“Most of what I was seeing were tree of heaven, mulberry, and locust, seeding in and forming a pretty dense canopy. There is also a lot of clonal growth, like sumac and sprouting,” She said. These dominant species were not planted: they are the ones that tend to swiftly take over urban spaces.
However, some of the planted trees had successful seedlings. “Of the planted trees there is a lot of great black cherry regeneration, which is not surprising because that’s something bird dispersed—that’s a huge factor in recruitment. But oaks were starting to fruit, the tilia was starting to seed, the celtis was even fruiting—and the hickories! We did see some hickory regeneration, which was pretty shocking.” The trees took well to Kissena.
She saw an ecological concept play out in the woods, “This idea that black locust, tree of heaven, mulberry, all of these really fast growing but short lived species seed in really aggressively, alter site conditions and theoretically shade themselves out eventually.”
Those fast-growing species make the site better for the oaks, hickories, black cherries, and basswoods that the project had planted, she explained. They shade those plants and drop leaf litter that puts nutrients back in the soil. Then, as the fast-growing species compete against each other and die for lack of light, they will, Danica thinks, make room for those desired species to rise up from the understory.
“It’s like relay floristics 101—it’s pretty cool,” she said, using the shorthand for a classic forest science concept.
In many ways, Kissena’s forest, like other urban forests, are fundamentally different from the woods of rural area. From the dirt up, urban forests experience different influences than rural ones. The park’s soil is deposited construction debris. Instead of windstorms and timber harvests, disturbances in urban forests include heavy human traffic and parks department weed control. Litter, dumping, tread-worn bare ground, and invasive species are omnipresent.
“We have a high edge to interior ratio which makes those spaces really susceptible to invasive species. There’s a whole host of unique circumstances for urban forestry.” And urban forests are so little studied. New guidelines are needed to effectively manage them, Danica said. “My study tries to capture the wealth of that—and think about looking at the urban forest as an ecosystem that has those disturbance regimes built into it.”
Human disturbance isn’t just a challenge. In some ways it’s the best part of the forest. Danica ran into visitors throughout her work. She observed that the mulberry foraging, opera singing, and wild camping all showed the strong relationships between people and the park. “All of those activities are directly enabled by these plantings,” she said. They showed Danica how forest spaces are needed in urban settings—and the roles that foresters can play in them.
“It gave me kind of perspective on the role of the urban ecologist. To not only bring scientific rigor to an understudied space but also to comfortably convey hypotheses and ideas to people on the ground.”
Danica’s research was supported by a YIBS small grant. She plans to build on her research at Kissena park, studying the successional dynamics of urban forests.