A long-range experiment is happening in West Philadelphia's Haddington Woods, a 40-acre urban forest, where experts, citizen scientists, and officials hope to find ways to restore and preserve city parklands, and find answers to dealing with invasive species, soil degradation, and even global warming.

"All of the [city's] forests are degraded," said Joan Blaustein, Philadelphia Parks and Recreation's director of urban forestry.

Haddington Woods, north of the 69th Street Transportation Center and east of Cobbs Creek Golf Club, was chosen as a testing ground because it has some of the most degraded - and some of the healthiest - forests in the city. It is home to many species of flora and fauna, offering both wooded and wetland habitats.

In the first half of 2015, Parks and Recreation removed harmful invasive plants and dead or unhealthy trees in a 23-acre area that had been fenced off to keep deer from disturbing the experiments within. Last fall, crews planted about 5,000 trees and shrubs, including native species of oak, dogwood, and hickory - all species present in healthy parts of the woods.

This winter, the fenced-off areas are free of the stray garbage and thorny vines that cover most of the woods. Mature trees are marked with a streak of blue paint, while saplings have plastic blue markers tied to them. Felled trees rest under a layer of wood chips and leaves, offering new habitats for foxes, raccoons, box turtles, and other wildlife.

When the Haddington Woods project began in 2014, homeless people lived on the grounds and about two-thirds of the area was degraded by invasive and overgrown plants.

"One of the main things was to remove invasive vines," Blaustein said. "They climb up trees that they will eventually bring down. A lot of them are grapevine and honeysuckle.

"They migrate from people's gardens," she added.

Parks and Recreation also has encountered the challenge of climate change.

"It's only in the past few years that we've realized we can't restore the way we did in the past," Blaustein said. "A lot of the species that are currently in our forest mix aren't going to be alive a hundred years from now. . . . The conditions are changing faster than ecosystems can manage."

The project was born during Michael DiBerardinis' tenure as deputy mayor in charge of Parks and Recreation under Mayor Michael Nutter, a position DiBerardinis held from April 2009 to January 2015.

DiBerardinis said he became aware of the importance of a forward-thinking plan to protect the long-term health of our natural resources when he managed natural areas statewide during Gov. Ed Rendell's administration.

"This is not a five-year or a 10-year program. It's a 50- or 70-year program that you have to pay a lot of attention to," said DiBerardinis, now managing director in Mayor Kenney's administration.

So far the cost of the entire project has been about $317,000, of which $58,000 went to pay for trees and shrubs, and $46,000 for fencing.

In addition to the $317,000, an additional $48,000 was spent on consulting scientists and for the citizen science programs.

The notion of community involvement has long been part of Parks and Recreation's mission, and DiBerardinis urged the department to seek ways to deepen this involvement.

"If you look at the literature that's out there, one of the most important things in making decisions on land use is having people involved who will be benefiting from the land," Blaustein said.

While Parks and Recreation has long worked with volunteers to help maintain its grounds, the Haddington Woods project is the first in the city to employ "citizen science" in both the planning and execution of experiments.

As part of this initiative, University of Pennsylvania lecturer David Hewitt taught a free class for community members in spring 2014. The class, which was primarily held at the nearby Haddington Branch of the Free Library, focused on ecological principals for city planning. That was followed up by another class on designing experiments.

John Janick, a Web developer who took Hewitt's class, said that other community-involvement efforts usually attract "a bunch of plant enthusiasts. . . . But [this class] was about half people from the nearby community who had an interest in the park. It was a really refreshing atmosphere."

After the classes, scientists, community members, and Parks and Recreation staff gathered to share their ideas.

"Everyone met together with data and maps all over the place, and you could walk around [and] make suggestions for what you'd like to see. . . . It was really up to anyone to come up with ideas on how to use the park spaces," Janick said.

Out of this collaborative effort emerged three experiments:

Density, which seeks to find the most healthy and cost-effective mix, size, and spacing of native tree species.

Biochar, which will address soil health, and seek to create soil conditions that will ensure invasive species don't return in restored areas.

Southern species, which will study nonnative species that could thrive in Philadelphia, many of them several hundred miles north of their natural range.

Results gathered at Haddington Woods will continuously shape Parks and Recreation's practices and plans.

The city expects the work at Haddington Woods to set an important precedent for the future of both forested and manicured parklands in Philadelphia.

"We're looking for best practices that can be applied across the system," DiBerardinis said.

That applies to both ecology and collaborative approaches. DiBerardinis said he urges Parks and Recreation to continue asking: "Where are the partnerships? Where are the organizations, institutions, and individuals who can work with us and help us manage the ecosystems at the highest level?"

Blaustein and Hewitt hope that as many individuals as possible will continue to be involved in the first round of data collection in May, and in reforestation efforts for years to come. More citizen-science classes will be held this year at Pennypack Park, another city forest.

And after what he's seen at Haddington Woods, Janick said: "I have a lot of hope for the city if that's a sample of what could happen. That kind of community involvement is what's necessary for what the city is trying to do."