Air Date: Week of January 5, 1996

Efforts are underway in Brooklyn, New York's Prospect Park to replenish the soil erosion caused by its millions of visitors. Modern ecologists are using a variety of techniques to help optimize the growth and health of vegetation in this 526-acre tract. Neal Rauch reports from the Borough of Brooklyn.

Transcript

CURWOOD: It's Living on Earth. I'm Steve Curwood. So let's say you live in Bedford Stuyvesant, one of Brooklyn, New York's poorest neighborhoods, or Park Slope, one of its wealthiest. How far away do you have to go to take a walk in the woods? Not that far, actually. You can just go a few blocks and be in Prospect Park. Back in the 1800s when Frederick Law Olmstead was busy creating parks in many of America's cities, he joined forces with Calvert Vaux in New York to create Prospect Park in Brooklyn, and its far more famous cousin in Manhattan, Central Park. And for years, Brooklynites have hiked and played in Prospect Park's half square mile of forest, which recreates the vast forests which once blanketed New York. There's only one problem. As the trees of Prospect Park grow older, none are sprouting to take their place. Neil Rauch has more from Brooklyn.

(Crows caw. Ambient voices)

RAUCH: To the casual observer, Prospect Park looks like it's in pretty good shape. There's plenty of greenery during the spring and summer, a mosaic of colors in the fall, and the scene of snow-covered trees in the winter can be breathtaking. But when going on a tour with an expert, it becomes clear that the 250 acres of woodlands, roughly half the park, are in trouble.

TOTH: There is no new generation of trees growing underneath the mature canopy trees of this forest. These are woods without a future. Essentially, the ecological processes have broken down.

RAUCH: Edward Toth, Director of Landscape Management for Prospect Park, says that ecological processes weren't that well understood when the park was created in the late 1860s by Frederick Law Olmstead and Calvert Vaux. The two men planned Prospect Park as a sculptured and manicured replica of rural New York, built around the remnant woodlands of western Long Island. It was intended to serve as a refuge from urban life, but Edward Toth says it soon became evident that the large number of visitors to the park were causing problems.

TOTH: Within the first years that the park was open, Olmstead was already writing about the serious impact of people trampling across new plantings.

RAUCH: Today, the 6 million visitors to the park each year means 12 million feet compacting the ground into a rock-hard surface. Now nothing can grow here, and severe erosion has resulted. In recent years mountain bikes have made the situation even worse. It's Edward Toth's job to reverse the woods' decline.

TOTH: What our challenge is as modern ecologists is to take our knowledge that we've gained in the 125 years since they've built this and look at how woods function and what they need to sustain themselves, and how that can happen in the face of this continued pressure from people.

RAUCH: These woods in fact have been under people pressure for hundreds of years. In the early 1600s forests here were cut down to make way for Dutch farms and then by the British for firewood. Later, Revolutionary War battles were fought on what is now park land. But the woods were never totally clear-cut at any one time. This allowed the forest to regenerate itself as farms and homes were abandoned. The current restoration project is trying to bring back this natural regeneration process.

ZIMMERMAN: We need to get over this rail first, so why don't we do that? Yes, we're going to break the law.

RAUCH: Landscape architect Christian Zimmerman and Edward Toth are using two strategies to help jump-start the process. On this badly eroded hill, they are taking active steps.

ZIMMERMAN: We're walking through an area that's filled with small plants that are anywhere from a foot or 2 to 3 feet tall. These are all native plants that were grown in our nursery. We grew over 20,000 plants for this project this summer and fall...

RAUCH: These wildflowers, along with logs placed on the hill, stabilize the soil. This will allow saplings that are now being planted to take root.

(Digging sounds.)

RAUCH: It was the perception that the woods are a haven for muggers that originally led to the cutting of the underbrush in the 60s and 70s. This left no plants to anchor the soil, and newly open land became an open invitation for all those feet. But the whole notion that more foliage leads to more crime may be a false one. Park administrator Tupper Thomas points out that the widely publicized murder of a teacher a few years ago, terrible as it was, was the only one in the 15 years she's been here. Not a bad statistic for this New York City borough.

THOMAS: It's 526 acres in the middle of Brooklyn. It's the safest place to be in Brooklyn. If you look at the crime rates in relationship to any other 526 acres.

RAUCH: Nevertheless, in a bow to the perception of crime, the new dense foliage will be planted some 10 feet back from the paths, with only low plantings right along the side to give park users more of a sense of security and, if necessary, a running start.

(Horns honking; traffic sounds)

RAUCH: This active landscaping work is being done in the middle of the park. Elsewhere a very different method is being tried.

ZIMMERMAN: Nature at work.

RAUCH: Landscape architect Christian Zimmerman reads one of the many signs posted around the park.

ZIMMERMAN: This area was once part of a forest. We are letting it slowly return to that state by not mowing the grass and by planting forest trees and shrubs. It may look overgrown to you, but nature is at work building a woodland. We need your help ...

RAUCH: Zimmerman and Toth take us along the edge of the park where this passive form of restoration is being used.

TOTH: There are processes in nature whereby a forest rebuilds itself if you start with essentially a meadow. That's a process of succession. If there are areas of the park that we're not going to get to for 15 years, if we stop mowing now and allow the woody plants to start growing again, nature will have done a great deal of work for us before we show up in our more active phase of dealing with that area.

RAUCH: One potentially controversial part of the restoration plan will be the removal of exotic trees put in by Olmstead and Vaux. The foreign trees have been aggressively reproducing, pushing out native species. One of these so-called weed trees, says Edward Toth, has firm roots planted in Brooklyn folklore.

TOTH: Tree of Heaven or ailanthus, which is known as the tree that grows in Brooklyn: the ailanthus tree was made famous by that story, and grows in most waste lots throughout the city. Although I have one in my back yard at home and I wouldn't cut it down for anything because it's the only thing we've got.

RAUCH: Cutting down mature, healthy trees in New York City parks is generally considered a sacrilege. But the Parks Department has made an exception in this case.

TOTH: Clearly these are four species where we can't coexist. And they weren't written about by Olmstead and Vaux as being integral to the design of the woodlands. I don't, in my heart of heart, think we'd have an argument with either Mr. Olmstead or Mr. Vaux at eliminating these four species.

RAUCH: Only saplings will be pulled at first. The mature trees won't be chopped down until after there are more native species filling the canopy. Even all this will not recreate a natural system. This park is a manmade setting, less than half of which is devoted to woods. The babbling brook, the duck pond, and the lake are all completely artificial, fed by the city's water system. Park administrator Tupper Thomas says Prospect Park is, after all, part of New York City.

THOMAS: The point is that it feels like you're in the Adirondacks, and you're not. You're in the middle of Brooklyn that doesn't have lakes. It doesn't have big mountainous hills. And it doesn't have rivers, and it doesn't have a forest. And this is the one place in Brooklyn where you'll find all that.

RAUCH: The restoration plan is expected to cost millions of dollars with $15 million coming from private fundraising and around another 28 from the cash-strapped city. But this may not really be a lot of money, considering that this project is going to take a quarter of a century. And as landscape management director Edward Toth says, the final results may not be known during most of our lifetimes.

TOTH: Long time is what we're about here. We're talking about processes that are going to take 50 to 100 years to tell us if we're succeeding at what we're doing. I think the reality is given the impacts that we have, that this will always continue.

RAUCH: For Living on Earth, I'm Neil Rauch in Brooklyn, New York.