A look at an urban forest (Hunter Island in the Bronx) that has been degraded and is
in need of restoration.
engaging hundreds of local volunteers to create more than five miles of
well-marked hiking trails,” explained Sarah Charlop-Powers, the executive
director of the NAC.
There are similar efforts underway in other forested natural areas
within the city. Alley Pond Park in northeastern Queens illustrates both the
indignities once suffered by natural areas in general and the promise of
restoration. Until the 1970s, the wetlands and forests of this 635-acre tract
were treated as dumping grounds both by city residents and by contractors
working on the Cross Island Parkway in the 1930s and the Long Island
Expressway in the 1950s.
Restoration of Alley Pond Park by a variety of collaborators began in
earnest in 1987. To date, 100 acres of the park have been restored, an
effort that included planting 58,000 native trees and shrubs with the help of
volunteers. Currently, NYC Parks is focusing on the final phase of work in
a 30-acre parcel on the east side of Alley Creek, where a coastal forest
desperately needed intervention. “The entire area was dominated by non-native invasive plant species, including woody vines like porcelain berry and
bittersweet that strangle and kill mature trees,” King said. After removing
hundreds of tires and other debris, the NRG applied strategic herbicide
treatments to remove invasive plants, then planted native trees, shrubs,
and herbs and provided supplemental irrigation and other forms of intensive
management during the natives’ establishment period. Now, hikers in this
section of Alley Pond Park can follow distinct trails amidst wildflowers and
newly established native trees like maple, birch, hickory, oak, hackberry,
sweetgum, and tulip poplar.
The NRG’s forest restoration process seeks to mimic natural succession
by establishing vertical layers of native species. Some of the native trees,
shrubs, and herbaceous plants are chosen for their ability to establish
rapidly, because closing canopy cover is essential. “Much of our canopy is
still broken from Hurricane Sandy and other recent
severe storms, and in urban areas, canopy gaps are
not a good thing – they facilitate the spread of our sun-
loving invasive species and basically just give us more
and more work to do,” King said.
The NRG’s approach to the restoration of natural
areas involves several innovative techniques. They
ensure that each layer of plant material performs a
vital function, while anticipating the future cultural
needs of the site as conditions change. For instance,
there are some versatile shrubs – such as elderberry, grey dogwood, and nannyberry viburnum – that
tolerate full sun but also do well in at least partial
shade. As such, those shrubs can serve as a nurse
crop to young trees.
Additionally, a strategy of planting a broad diversity
of species offers the forests greater protection against
the threat of exotic insects, which can devastate a
monoculture. There’s a special emphasis on choosing
plants that have mutually reinforcing, highly adaptive
seed dispersal – for instance, the silky dogwood shrub, which fruits in late
summer, attracting migrating songbirds that also consume the blue fruits of
the tupelo tree that are out at that time.
King feels that it’s important to focus on projects in large areas with
“core” forest (forest parcels that are as far as possible from the forest’s
boundary). Projects are prioritized based on ecological landscape connectivity
and prior investment. And she doesn’t want anything that has already been
restored to revert back to being fully invaded by invasives, so restored areas
are swept annually for the first two years to remove non-native species, and
subsequently at 18-month intervals until the newly planted tree canopy closes
(which can take decades).
The sheer scale of the project means that it will continue for decades, but
King says that she has a clear vision of a time when “all forested areas are
dominated by native species and that invasive species have been managed
to the point that natural forest regeneration is occurring.”
The Forest Restoration team unloading a large delivery of
native trees in Alley Pond Park, Queens.