Page 1

ANDROPOGON'S ONLY COPY PLEASE RETURN

Andropogon Associates, Ltd.

I

\

Phase One Report: Consensus of the Interv~e~s, Key Issues & Initial Program RecommendatioJ\s \

-

October 1989 Architects, Landscape Architects & Planners

(215) 487-0700

Fax: (215) 483-7520


Landscape Management & Restoration Program for the Woodlands of Central Park Phase One Report: Consensus of the Interviews, Key Issues & Initial Program Recommendations

October 1989

Submitted to Central Park Administration The Arsenal Building Central Park New York, New York 10021 Prepared by Andropogon Associates, Ltd. Ecological Planning & Design Consultants Architects, Landscape Architects & Planners 374 Shurs Lane, Philadelphia PA 19128 Phone: 215-487-0700 FAX: 215-483-7520 Project Director: Leslie Sauer Project Staff: Jose Alminafia, Judith Fitch & Rolf Sauer


Landscape Management & Restoration Program for the Woodlands of Central Park Phase One Report: Consensus of the Interviews, Key Issues & Initial Program Recommendations Contents

page

Key Map of the Woodlands of Central Park

2

Summary: Landscape Management & Restoration Program for the Woodlands of Central Park

3

Introduction: The Purpose, Process, and Participants of this Study

4

Consensus of the Interviews and Key Issues Park Activities That Currently Damage the Woodlands: Off-trail Use of Bicycles and Vehicles, and Trampling Stormwater Management The Spread of Exotic Invasive Vegetation Maintenance & Security Education & Signage

9 10 14 15 24 27

The Approach & Framework of the Landscape Management & Restoration Program

30

Assessment of Current Conditions & Initial Program Recommendations The North Woods The Ramble The Hallett Nature Sanctuary A Habitat Corridor Network: Vegetation Management Elsewhere in Central Park to Foster Diversity in the Woodlands Soil Rehabilitation & Establishment of a Soil-Making Operation at the Mount Bibliography

37 37 44 48 51 53 55


Key Map of the Woodlands of Central Park

.. .. r===:;~:=-====='5.:::;;;;;;;;;;;;;;:::;;;;;;;;;;:;:;;;:. ~ '----' --------''-----' ~ If. .& .. ,

.I

I

••••

~

r=;:'==;====:=.;;i'S

,~~

.... " I....

I~'--"

r-----'I"""---' . - - - - . , - - - - . , - - ,

,...

I."

.. __

r----'l..---...~

~

.~"

It'

~

.----.,-,., - - - " , - - - , r - - \ ' - -''''''II

o - l ~ ~ , - - ., - - - . . , - . , . -

'_'II

1.1'

Hallet Nature Sanctuary

II

.I"'" "'.

The Ramble

North Woods Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

2

....


Summary: Landscape Management & Restoration Program for the Woodlands of Central Park The woodlands of Central Park, which include the Hallett Nature Sanctuary, the Ramble, and the extensive forests of the North End, have deteriorated significantly over the past years. Erosion and bare, compacted soil are increasing in extent and a few aggressive exotic species are naturalizing throughout, displacing valued native plant communities and remnant planted landscapes. At the same time, the infrastructure of paths, bridges, and stormwater facilities is in dire need of repair. Despite growing concern, effective action in the woodlands has been delayed because of the lack of any clear consensus on appropriate policies and procedures. A sequence of interviews and site visits in 1988 initiated a planning, design, and implementation process which is intended to be as fully participatory as possible to ensure that those who will use and care for the park over time have a strong role in determining how the woodlands are restored and managed. . The major long-term goals and policies for each woodland area were reviewed as well as the major issues which need to be resolved. This report outlines initial program recommendations which represent the general consensus of this first phase. The first priorities identified were to initiate effective control of those activities which currently damage the woodlands, including the misuse of vehicles and bicycles, trampling, and stormwater management. Secondly, immediate management is recommended to stabilize all bare soil and eroded sites and to develop an ongoing program for the gradual control of invasive exotic vegetation. The establishment of a Forest Management Team is suggested to carry out this work, which is long term, labor intensive, and specialized. To better address the need for greater security and education, significant increases in the Urban Rangers Program are also proposed, as well as additional interpretive programs. Subsequent phases will address the development of more comprehensive planning and design documentation which will be subject to extensive aesthetic, programmatic, and environmental review by the community, park staff, and regulatory agencies. The goal is to restore both the aesthetic drama and historic character of these woodlands while fully protecting and enhancing their habitat values for future generations.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

3


Introduction: The Purpose, Process, and Participants of this Study The woodlands of Central Park comprise three major areas: the 4-acre Hallett Nature Sanctuary in the southeastern section of the park; the Ramble, a 38-acre site in the center of the park that is both famed for birdwatching and for its intricate Olmstedean design; and an intermittent forest of over 90 acres which occupies the northwestern corner of the park. Like the rest of Central Park, none is truly a natural landscape; all three sites were subject to extensive grading, drainage alterations, and planting when the park was developed over a century ago. Now, however, they feel very natural in character, especially in contrast with the rest of the park, and represent for millions of people a retreat from the city that surrounds them and a contact with nature and the forest which once blanketed the entire region. Today, there is increasing concern over the condition of these woodlands, as the consequences of past neglect and the stresses of the urban environment become more visible. Eroded or compacted bare soil covers large areas and exotic invasive vegetation, naturalized from earlier plantings, now threatens to overwhelm and displace developing native habitats. The infrastructures of historic features, drainage, and paths are in need of complete reconstruction. The vistas and dramatically crafted views of the original design are now obscured by overgrown plantings and volunteer vegetation. In 1984, the Central Park Conservancy, in conjunction with the New York City Department of Parks & Recreation, published a report, entitled Rebuilding Central Park: A Management & Restoration Plan, which outlines a remarkable effort, initiated in 1977, to systematically restore the fabric of the entire park, a goal which is paralleled only by the initial establishment of the park under Olmsted and Vaux's Greensward Plan. Following the broad outlines of this 1984 report, it is the purpose of this study to delineate a Landscape Management & Restoration Program for the Woodlands of Central Park. Forest reclamation, despite its laudable goal, is the subject of considerable controversy, because there is limited experience and documentation of urban restoration projects. Often there is little agreement on the goals of landscape management, especially when the site is a heavily used and historic landscape; Central Park is an excellent example of this. Recently, tree removals to restore a vista in the Ramble sparked enough protest to cause the abandonment of the restoration effort. Tree clearance, in general, is unilaterally opposed and against current policy. Indeed, any change or unfamiliar activity is likely to be regarded with suspicion by park users. Even amongst the scientific community, there are conflicting opinions on landscape management. When management is undertaken, it often leads to frequent policy shifts in reaction to each comment raised, which only subjects the landscape to additional stress. Wildlife advocates often recommend plant species which are recognized as invasive pests by plant ecologists. Similarly, foresters often recommend clearing canopy trees to stimulate the growth of native shrub and understory layers, which can trigger the invasion of exotic disturbance species instead. Still others, leery of the results of past Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

4


management efforts, advocate allowing "nature to take her course", despite clear evidence of continued deterioration of native plant communities. Unfortunately, the consequences of letting parkland habitats "take their course" can be severe. Neglect may permit exotic species to overwhelm a site and erosion and trampling to go unchecked. Uncertainties about policy and funding restrictions also result in inaction. At the present time, for example, little is done in the woodland areas of the park beyond occasional trash removal. Effective landscape management must be continuous and incremental. The most critical component of a successful approach will be achieving real consensus on the goals and principles of landscape management. The genuine participation of the full spectrum of interested parties is necessary to ensure adequate support for a coherent effort that can be sustained over time. In order to address these complex issues and produce a plan which has a broad base of support, a major component of this phase of the program was a key informant survey. From July through September 1988, a sequence of interviews was conducted with individuals who have been involved with the Central Park woodlands. The purpose of these interviews was to identify the significant areas of concern in the woodlands and to clarify where there was consensus or disagreement, as well as to recommend strategies to reconcile seemingly conflicting needs and viewpoints. At the same time, the interview process was augmented by preliminary field reviews to assess current conditions of the three woodland areas in the park. The sources of stress and extent of damage were evaluated as well as the general health of the vegetation. The directions of changes in the landscape were also recorded and correlated with prevailing trends elsewhere in the urban environment. A draft report was prepared at the conclusion of this phase and was circulated to all participants and other interested parties for comment and then revised to incorporate comments received. This report is intended to provide the foundation for a policy in developing a Landscape Management & Restoration Program for the Woodlands of Central Park. Part One of this report summarizes the key issues raised in the interviews and field studies. Part Two describes a preliminary assessment of the current condition of each of the three woodland sites and an initial restoration program. It is hoped that this phase represents the first step in a truly participatory design

process. We wish to express our gratitude to the following individuals who gave of their time, expertise, and concerns in this effort. We look forward to working with them in the future to realize this challenging program and invite others who are interested to join in this effort. Continued public participation in the development of this program is encouraged. Please send your comments to: Marianne Cramer, Central Park Administration, The Arsenal, Room 236, Central Park, New York NY 10021.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

5


List of Parties Interviewed: New York City Department of Parks & Recreation and the Central Park Conservancy Henry J. Stern Elizabeth Barlow Rodgers Tobi Bergman Marianne Cramer Neil Calvanese Geraldine Weinstein Marc Matsil Sally Austin William B. Lough Theresa LoPiccolo Yap Richard Kruzansky Laura Starr David Carlson Cecile Loomis Furman Horton Terese Braddick Carol Anastasia Erik Lauer Lee Henry Sgt. Gerard Rosato Daniel Smolanick

Commissioner, Parks & Recreation Central Park Administrator Chief of Operations, Central Park Chief of Design & Planning, Central Park Director of Horticulture, Central Park Former Director of Horticulture, Central Park Director, Natural Resources Group, Parks & Recreation Director of Education, Central Park Chief of Forestry, Parks & Recreation Soil Conservation Program Coordinator, Central Park Soil Conservation Program Assistant, Central Park Assistant Landscape Architect, Central Park Landscape Architect, Parks & Recreation, Capital Projects Natural Resources Specialist, Parks & Recreation Tree Care Coordinator, Central Park Director, Urban Park Rangers Urban Park Ranger Urban Park Ranger Park Enforcement Patrol Officer Supervisor, CPOP, Police Department, Central Park Precinct Officer, CPOP, Police Department, Central Park Precinct

Friends of Central Park Robert Makla

President

Community Board Representatives John Levitt Daniel Karpus Elizabeth Finkel Eileen Burney

Member, Community Board #5 Member, Community Board #7 Member, Community Board #8 Member, Community Board #10

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

6


New York City AudubonSodety Geoffrey Ryan Norman Stotz Starr Sapir

President Past President Board Member

Linnaean Society John Farrand, Jr.

Member, Naturalist & Writer

Bird Walk Tour Leader Sarah Elliott

Central Park Naturalist

Landscape Architecture Consultant Bruce Kelly

Landscape Architect

and the many park patrons who freely gave short impromptu interviews when approached on site and asked about their use of, and concerns for, the woodlands路 of Central Park.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

7


Draft Comn1ents on the First-Draft Report Were Received From: New York City Department of Parks & Recreation and the Central Park Conservancy Tobi Bergman Marianne Cramer Neil Calvanese Geraldine Weinstein Marc Matsil Sally Austin Richard Kruzansky Furman Horton

Chief of Operations, Central Park Chief of Design & Planning, Central Park Director of Horticulture, Central Park Former Director of Horticulture, Central Park Director, Natural Resources Group, Parks & Recreation Director of Education, Central Park Soil Conservation Program Assistant, Central Park Tree Care Coordinator, Central Park

Northwest Central Park, Multiblock Association, Inc. New York City Audubon Society, Conservation Committee Geoffrey Ryan Albert Appleton Norman Stotz Starr Sapir John Seirup

Member, Central Park Subcommittee Member, Central Park Subcommittee Member, Central Park Subcommittee Member, Central Park Subcommittee Member, Central Park Subcommittee

Linnaean Society John Farrand, Jr.

Member, Naturalist and Writer

Friends of Central Park Robert Makla

President, Friends of Central Park

Additional Respondents Nicholas Wagerik Roger F. Pasquier M. M. Graff

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

8


Consensus of the Interviews and Key Issues While nature herself is remarkably variable, disturbance is typically simplistic. When disturbance is uncontrolled, deterioration usually accelerates and a once rich site steadily diminishes in diversity, value, and interest. There are so many sources of disturbance in the modern urban environment that it is often all too easy to assume that solutions are too complicated to implement. The Park and its public, for example, were frequently described as "unmanageable" during the interview process. Air pollution is visible and extreme, and seems beyond the Park's control, but urban wildlands can be sustained over time only if we succeed, through management, to prevent further damage and compensate for such environmental stresses. More important, however, is the fact that the greater share of disturbance is due to the nature of human activities, not environmental conditions. These changes, observable in the woodlands of the Park, can also be seen in woodlands of rural parklands as well. The intensity of use is certainly problematic, and a growing stress on parklands, yet this is also the very reason most parks exist: to be used by people. A major goal of this report is to assist the Parks & Recreation Department in confronting and changing those uses and activities which damage the landscape, rather than looking for a "miracle plant" which will take extensive trampling, or seeking a commitment to replant promptly after damage occurs. Once disturbance is controlled, the landscape will become far more able to renew itself. The task of restoration is immense and recovery will not happen overnight, and it is necessary to set priorities. Rather than trying to deal with everything, this program focuses on a few critical activities, in order to effect significant changes for the better, to reverse the process of deterioration, and to initiate recovery. Despite the complexity of urban systems, there are actually only a few major stresses that account for the bulk of disturbance. Four general management issues were raised time and again. They include: (1) landscape disturbance from certain park activities -the off-trail use of bicycles and vehicles, and trampling; (2) stormwater management; (3) the proliferation of invasive exotic vegetation; and (4) the lack of maintenance and security. These are the most severe problems in the woodlands of Central Park and set the framework for management and restoration program. They must be tackled directly, for until they are resolved, true restoration will remain an illusion. Not surprisingly, these are also park-wide problems which are chronically faced by nearly every park manager. Happily, there was not only broad consensus on the nature of these problems, but near unanimity on appropriate solutions. In this report, the activities which damage the woodlands will be reviewed and general recommendations will be summarized. This is followed by a proposed framework for a restoration and initial program recommendations for the three woodland areas.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

9


Park Activities That Currently Damage the Woodlands Inappropriate behavior abounds in the park, both intentional and inadvertent. Though often very problematic, it is a testament to the important and exhilarating sense of freedom people experience in the park -- and the woodlands feel the wildest of all. The primary activities which directly damage vegetation and disturb the soil surface include the off-trail use of bicycles and vehicles and trampling. Additional erosion and sedimentation results from uncontrolled stormwater. The spread of exotic vegetation is the most visible consequence of these and other urban stresses.

Off-Trail Use of Bicycles The off-trail use of bicycles is a serious and presently completely uncontrolled problem in the woodlands, except for the Hallett Sanctuary which is fenced. Sections of the Ramble have been completely decimated and a whole sequence of new outlaw trails made by bikers was opened this year in the North End. Cyclists travel from all over the city to tackle the steep topography and rocky outcrops found in Central Park. Enforcement is very difficult, since bicyclists are not easily pursued except by another off-trail vehicle which, in turn, also damages vegetation. Their activity often goes unnoticed in the forested sections of the park. Bicyclists have a place in the park and often feel strongly that this includes the wooded sites, whether or not they are aware of the damage they cause. A special task force should be appointed to develop a program to control off-trail use of bicycles. The effort should be initiated immediately and widely publicized. Bicycling restrictions should be delineated clearly in all signage and park guide materials. Log posts along borders have been effective in deterring bicyclists and should be considered here. The cooperation of organized bicycle groups should be sought, and should include a census and interviews. It is likely that meeting the needs of bicyclists elsewhere in the park will be integral to effective negotiation. Patrols should be initiated. Security personnel should issue citations consistently and request full cooperation and strictness from the courts. A study should be undertaken to evaluate how frequently a citation actually results in a fine and whether or not inadequate identification is a problem in enforcement. It may be necessary to increase the use of confiscation as an action where identification is inadequate or to pursue the option of bicycle registration and licensing. 'Hot spots' for illegal use should be targeted for extra security personnel during likely periods of high use. The task force should report periodically on its effectiveness to the Central Park Administrator.

Off-Trail Use of Vehicles Vehicular traffic also poses problems for the woodlands, most particularly in the North End. There is no traffic in the Hallett Sanctuary, because the fence prevents access, nor is there, at present, any anticipated need for vehicular use during the restoration process. The pathways in the Ramble are wide enough to permit the use of smaller vehicles, such as pick-up trucks belonging to the Parks & Recreation Department and police. The existing routes will also provide adequate access during Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

10


the reconstruction of the architectural features and drainage infrastructure. The greatest access problems occur in the North Woods, where the steep topography, narrow trails, and frequent stairs severely limit vehicular use. In the North End, where all patrols are in pairs and in vehicles, no routine security is provided for the woodland areas because of restricted access. When access is necessary, damage is incurred. Where there are stairs, bypass trails become established. Where there are no pathways, off-trail use may occur, for example, for police activities. Path routes should be recognized as critical during further restoration efforts and may in places require widening and the elimination of stairways. An assessment of existing paths and access should be initiated to delineate an appropriate design program which meets current needs while respecting historic character. Even where the path design is adequate, additional problems occur because many of the Parks & Recreation Department's vehicles are simply too large for the paths. Trucks continuously erode and compact path margins. The vehicular service fleet should be down-scaled to provide smaller vehicles suited for use on the narrower and curvilinear woodland trails. Specific recommendations are provided in "The Central Park Management Study", prepared in 1988 by the consulting firm of Deloitte, Haskins & Sells. The Parks & Recreation Department is currently attempting to curtail unnecessary traffic in the Park, especially by its own personnel shortcutting through the Park. While any apparent restriction on convenience is typically resisted, these efforts should be applauded and expanded. This is especially important in the woodlands, where the presence of vehicles represents a very noticeable intrusion. During the restoration work, the size and use of vehicles should be minimized whenever feasible.

Trampling Controlling trampling would make the single greatest improvement to the health of the woodlands of Central Park. The problems of trampling are further aggravated by the fact that many of the steepest slopes in the Park's woodlands are constructed of fill, often over bedrock, and are simply not as stable as a natural slope. Once soil loss commences, it tends to proceed rapidly through the softer fill soil, encountering no layers of more resistant gravelly layers or fractured bedrock beneath. Under such conditions, it is imperative to maintain vegetative cover. The decline of the landscape following trampling is a familiar scenario: it begins with damage to herbaceous and small woody vegetation. No less important is the fact that, once exposed, soils continue to deteriorate. Plants improve soil by adding organic matter and by loosening compacted layers. Without vegetative cover, no organic matter is added and rain-splash action alone, without further trampling, will increase compaction. In combination with air-borne pollutants, an impermeable surface or crust is formed, which reduces the infiltration of water and inhibits air circulation, producing harmful levels of carbon dioxide.

Phase One; Landscape Management & Restoration Program for the Woodlands of Central Park

11


Once exposed, a trampled trail often is well used and becomes in itself an incentive to further trampling. At the same time, maintenance of the original paths has been long deferred and the paths are now severely deteriorated. In many places, a desire line is often hard to distinguish from an original path. Until the paths are rebuilt, it is unreasonable to expect the visitor to keep to them. Therefore, restoration of the path infrastructure should be given the highest priority and should precede major replanting efforts. Bare soil is not an acceptable path surface in Central Park. All bare-earth, desire-line trails should be eradicated and revegetated and all areas of bare soil should be restabilized. When bare soil is visible anywhere, trampling is undertaken far more casually than when paths are well maintained and erosion well controlled. One of the most difficult aspects of trampling is that much of it is deliberate. People often are attempting to find seclusion in the vegetation, for private encounters, or simply for the sake of feeling removed from civilization. At other times, people want only to achieve greater intimacy with the landscape, to come closer to the water's edge, for example. It has been the general intention of the park's restorers to maintain the original

Olmstedean path system, insofar as is feasible, in part because the total number of visitors today is not much more than when it was new -- up to 10 million visitors per year then and roughly 12 million per year today. Except where use patterns have changed, due to new features, this has been a reasonable goal and has retained much of the character and intent of the original design. However, this is always a balancing act which requires a measure of judgment. The original path system, while exceptionally well planned, was not designed for the park user of today, who is often more informal and less confined than the Victorian-era stroller. Tour groups today do not, for example, confine themselves to walking on paths, usually for good reasons from an interpretive perspective. This need should be accommodated without resulting in trampling. The addition of a few standing places where a group can gather and a limited sequence of very short adventure trails, narrow in width, designed for single-file walking might permit access to selected special areas without trampling and eliminate ambient disturbance. Ideally, these trails should not look like paths at all, but simply be comprised of large stepping stones and buried rocks which appear to be bedrock yet provide a hard surface with minimal upkeep. This rocky aspect is also in character with Central Park and should mimic existing outcrops, which, of course, are already often chosen as clambering places. Using "boulders and other large scale systems to hold soil" was also recommended in the "Soil Survey and Management Report" prepared by the Central Park Conservancy in 1981. These adventure trails could typically occur as short loops off existing trails at selected sites, some of which were designated by tour leaders during the interview process. The gathering areas along the small walking loops could be constructed of a variety of surfaces, including 'bedrock', gravel, stabilized earth, or other materials which appear more natural in character. The object of these trails is to provide adequate protection of those areas which are routinely trampled just off trail, as well as to provide enough footing and direction without establishing a Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

12


full-fledged paved path. This recommendation is not intended to propose a new secondary trail system or to suggest an extensive new path development. Only the minimum should be considered and further evaluation is required. A more subtle aspect of erosion has to do with the psychology of trampling and the kinds of spaces that are provided by the vegetation. Wherever privacy is desired, very dense shrub-form vegetation is sought which serves as a visual screen. Brushy vegetation close to the pathway, rather than confining the walker, may actually serve as an incentive to leave the path. When one site, for example, is pounded into oblivion, it is abandoned in favor of another site, until the former site recovers and is once again used. Throughout the Ramble and North End, these conditions seem to prevail; however, further investigation of trampling patterns is necessary. In contrast, the more open character of the mature forest areas actually affords less cover and is less trampled by those seeking shelter than sites with more privacy. Nearly every previous management recommendation has urged thinning of the woodland canopy, in order to stimulate dense shrub and understory growth. This also reflects the conventional wisdom of most foresters. However, this approach poses major problems in the woodland areas of the Park. None of the woodlands yet has anywhere near the canopy cover of a typical healthy native forest in the region; nor is a forest a place to favor specimen shrubs or specimen trees for that matter. The round canopy of an open-grown specimen is not the forest ideal, but reflects a gardener's or horticulturalist's goal instead. If this forest were a vast expansive, unbroken, and undisturbed tract, then creating openings and some canopy thinning might greatly diversify the habitat and favor desirable shrubs and herbaceous growth as well as canopy reproduction. But these woodlands are, instead, fragmented and disturbed, with a discontinuous canopy. Successional species, such as black cherry, black locust, and mulberry, often prevail and it is these species, as well as invasives, which would be favored by thinning, not the more desirable mast species of oak, hickory, and beech. Where invasive exotic vegetation is established, openings in the canopy are likely to lead to rampant growth of disturbance species, rather than favoring more diverse native vegetation. Elsewhere, nursery-grown shrubs may be densely planted beneath the newly opened canopy. The round, bushy, newly planted shrubs seem to discourage trampling for awhile, but once they become head-high and serve as a visual screen, they attract those who wish to hide behind them and the decline begins. Dense, round shrub mounds should, instead, be confined to planting beds in turf areas, where security is less problematic and plantings more easily replaced. In contrast, another conventional woodland treatment is to clear away most of the shrub and understory layers to provide complete visibility. This is often perceived as a useful security measure and vigorously pursued after a notable crime has occurred. Unfortunately, erosion is usually a consequence and native communities are eliminated even before they can be trampled away. Only disturbance species are favored by such overkill tactics. Security needs can be amply met with sounder management techniques. A healthy, well-managed forest landscape is multi-layered, not simply comprised of two layers, and is far more varied in charader than either an open understoryless woodland or a dense shrub mass with a few specimen trees. In addition, wildlife is Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

13


favored in forested areas with diversity of plant forms as well as species. A high level of foliage height diversity is typical of many areas which support a wide variety of birds. A native forest is typically more open than the knotweed patches or horticultural shrubs and more layered than the cleared woodland, both of which have very little diversity of form. The understory would, for example, be comprised of open-branching spicebush and maple-leaf viburnum, as well as leggy sassafras and dogwood, all incidentally with high lipid fruits of exceptional value to wildlife, especially migratory birds. Like many other areas of the park, the woodlands are used by the homeless. The Hallett Sanctuary and sections of the North Woods, which are not routinely patrolled and have sources of city water, support fairly large and constant homeless populations, especially during the warmer months. Each encampment site is reduced to bare soil fairly quickly. At present, there is a patrol for the homeless run by the Human Resources Administration, which seeks to escort individuals out of the Park and to a hospital or shelter if they accept it. The Central Park Daybook, for example, has logged about 100 individuals daily leaving the Park during morning clean-up, although this is far from the entire population. While the problems of the homeless cannot be solved within the boundaries of the Park, the Park's administration must work closely with homeless support groups. A related problem is the use of the Park for toilet facilities .. Not only is undue trampling a consequence, but landscape and maintenance crews are faced wi th a clean-up problem which they are poorly equipped to deal with. A greater number of public toilets is essential and the problem is compounded by a shortage of facilities city wide. Every park manager is familiar with the almost insurmountable difficulty of maintaining clean and safe restrooms; however, appropriate use of the. Park is impossible without them, especially for the very young and old or those who have travelled a distance or intend to stay awhile. This issue was raised again and again during the interviews. Rebuilding Central Park: A Management & Restoration Plan strongly recommended adequate maintenance and the reopening of all closed facilities. The subsequent Central Park Management Study reiterated this recommendation and advised on appropriate maintenance equipment. In most cases, full-time staffing will also be needed to provide an acceptable level of security.

Storrnwater Management Stormwater damage in Central Park was also a matter of concern. Urban woodlands are often surrounded by city outfall pipes, which creates deep stormwater gullies; however, such extreme conditions do not typify Central Park, which is hydrologically separate from its surroundings. To accompany the extensive recontouring of the terrain that went into the creation of Central Park, Olmsted and Vaux designed a comprehensive system of surface and subsurface drainage. Although in need of maintenance and no longer functioning in places, this infrastructure still provides a remarkable level of protection. There are, however, problems associated with the increase in runoff. The stream courses, both natural and artificial, show the greatest stress. The stream and water bodies in the North End, modified from the earlier Montayne's Rivulet, are filled with sediment and subject to erosion in places, due Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

14


primarily to changes in drainage in the watershed which have occurred since the park was established. Additional facilities and impervious surfaces, the conversion of tall grass meadow to turf, soil compaction, and erosion over time have all increased runoff, producing larger volumes of water and sediment than the original system was designed to accommodate. The Gill in the Ramble, an entirely artificial watercourse, has been impacted by heavy loads of silt from eroding side slopes and severe trampling along its banks. The major hydrologic systems in the woodlands should be monitored and modeled, and a stormwater management plan developed for each site. Where watershed boundaries go beyond the limits of the woodland, the management plan should address the whole watershed. This information will be critical to restoring the stream channels as well as to rebuilding the stormwater infrastructure, especially in the North End where the hydrology has been significantly altered over time. The strict replication of the original design would not withstand the present storrnwater loads which the streams now carry. Once adequate hydrologic data are available, the design of the drainage infrastructure can be modified as necessary or runoff controlled in the upper watershed. Any proposed alterations in the path system should also be included in the drainage review. The stormwater management plans should be designed to maximize recharge of groundwater and minimize runoff, providing greater levels of retention and infiltration than were realized in the original design. This also will help support vegetation in times of drought. In the North End, for example, all woodland areas should have a buffering margin of tall grass and wildflower meadows, rather than turf or paving. Any restoration of landscapes adjacent to woodlands should achieve effective erosion and sedimentation control, both during and after construction, and be designed to improve retention over existing conditions for the low volume, high frequency storm (a two-year storm), as well as the high volume, low frequency storm (a lOO-year storm). The recent restoration of turfed areas in the park has generally favored reduced compaction and increased infiltration, which is consistent with these goals. However, greater levels of stormwater retention should be incorporated in the design criteria. The restoration of paths is integral to realizing the storrnwater management plan and, in conjunction with drainage features, should be given very high priority. Both are necessary to appropriate utilization of the park and the control of erosion and disturbance, and should precede major landscape restoration. The second major goal of stormwater management in the woodlands should be to restabilize and revegetate all existing areas of bare soil. Appropriate restoration techniques are described later in this report.

The Spread of Exotic Invasive Vegetation While erosion is the most visible aspect of environmental damage in the woodlands of the Park, the spread of exotic invasive vegetation is perhaps the most pernicious consequence. Planted woodlands and native forests alike can be overwhelmed by exotics and end up looking like overgrown vacant lots, if adequate control is not undertaken quickly enough. All stages of this process can be seen in the Central Park woodlands, from initial introduction of a pest species to complete takeover. Three Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

15


species -- Norway maple, sycamore maple, and Japanese knotweed -- currently account for the bulk of the problem in the Park. In the last century, both Norway and sycamore maples were widely disseminated.by nurserymen, horticulturalists, and landscape architects, and are still cultivated on a massive scale. Like many other disturbance species, their vigor in our landscape and easy propagation are part of what made them so popular. Many nurseries in the region today have more varieties of Norway maple than all other maples combined. Japanese knotweed, in contrast, requires far less help from propagators and planters to accomplish its phenomenal increase in range. Planted earlier in this century, it was soon abandoned because it grew out of bounds so quickly. Although a few suppliers claim to have a non-rampant variety, Japanese knotweed is now almost unavailable in the trade. Yet today, there is hardly a corner of Central Park, except for lawn and intensively maintained beds, where knotweed cannot be found. Its spread throughout the region is equally spectacular and it can be readily found up and down the east coast. While vegetation, in general, is usually perceived as providing soil stability, knotweed and both Asian maples actually provide very poor erosion control, as compared with healthy native communities or well maintained horticultural landscapes. Norway and sycamore maple have very large and thick dark leaves which emerge early in the spring and typically fall off the tree long after those of the native maples, creating a shade so dark that it severely inhibits ground layer vegetation. Even more problematic is the fact that Norway and sycamore maples appear to be strongly allelopathic, that is, they suppress the growth of other plant species due to the release of toxic substances in the soil. As a result, once Norway or sycamore maple become established, reproduction of other species comes to a halt and the ground beneath them is often totally barren. Without the additional protection of ground layer and/ or small tree and shrub vegetation, the root systems of the trees do not provide adequate stabilization. Even more devastating, of course, is the loss of native plant communities or valuable planted vegetation. Japanese knotweed is an even greater failure at site stabilization. Although large in size, often up to eight feet or more height, this plant is actually a stout-stemmed herbaceous plant which dies completely back to the ground each winter, leaving no winter cover. This problem is compounded by the fact that knotweed lacks a fibrous root system, which would provide greater soil stability. Spreading quickly by rhizomes, it soon displaces other more stabilizing vegetation completely. Given its behavior pattern, it may also be allelopathic. There are, at present, no effective natural controls for these plants. Even though Norway maple, for example, is subject to numerous diseases and pests which create problems in horticultural settings, as yet none has checked its spread in the wild. Over time, it is inevitable that some organism will take advantage of so widespread a host but, in the meantime, extensive areas of native habitat are being decimated and their recovery is severely hampered by a wide range of other environmental stresses. A major effort will be required to repair the damage done.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

16


It is strongly recommended that no species which has demonstrated itself to be a

successful invader at the expense of native habitats in the region, or is even suspected of being a pest, be planted in Central Park, because of the threat they pose to the woodlands, planted sites, and regional natural areas. This is a conservative policy, but the consequences of being too optimistic may be very costly to remnant habitats. Urban wildlands are already severely stressed and it is important not to compound that risk. This is especially relevant to woodland areas, where it is desired that nature take its course as much as possible. What makes a plant an exotic invader, instead of a simple garden escapee? It is all a question of degree and context; how fast, how widespread, and most importantly to what extent does it displace native habitats. Appropriate evaluation of exotics requires careful observation of their behavior throughout the region. It is critical to identify what we call 'Huns', those plants which are not only reproducing rapidly in highly disturbed sites, such as vacant lots, but are also making significant inroads in less disturbed areas, such as large woodlots. The most conspicuous trait of a 'Hun' is that it displaces whole communities, not just a few species. No one looking at plants in the eastern corridor, for example, can fail to have observed knotweed and Norway maple. There is already more than enough evidence to alert any park manager to the seriousness of the threat these pose to native habitats. A park-wide ban may seem extreme, however, many of the species are dispersed by birds and quickly traffic over fairly large distances. All are extremely difficult to eradicate once established and none is so critical to the landscape character of the park that it cannot be replaced by another less threatening species. Beyond jeopardizing native habitats, invasive species typically represent a significant maintenance drain on more horticultural landscapes and often out-compete desirable exotics as well as indigenous species. It is strongly recommended that the following species be banned from being planted,

and their presence controlled, in Central Park:

Norway maple Sycamore maple Russian olive Autumn olive Osage orange White mulberry White cottonwood

(Acer platanoides) (Acer pseudoplatanus) (Eleagnus angustifolia) (Eleagnus umbellatus) (Maclura pomifera) (Morus alba) (Populus alba)

Shrubs & Small Trees Barberry Winged euonymous

(Berberis japonica) (Euonymous alatus)

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

17


Amur honeysuckle Tartarian honeysuckle Blunt-leaved privet Smooth buckthorn Shining buckthorn Multiflora rose Rugose rose

(Lonicera maackii) (Lonicera tatarica) (Ligustrum obtusifolium) (Rhamnus cathartica) (Rhamnus frangula) (Rosa multiflora) (Rosa rugosa)

Porcelain berry Oriental bittersweet Japanese honeysuckle Kudzu Japanese wisteria

(Ampelopsis brevipedunculata) (Celastrus orbiculata) (Lonicera japonica) (Pueraria lobata) (Wisteria floribunda)

Herbaceous Plants Purple loosestrife Japanese knotweed

(Lythrum salicaria) (Polygonum cuspidatum)

There is as yet no consensus on this preliminary list of plants which are proposed as unsuitable for use in the Park and further evaluation is needed. Several species recommended in this Park-wide ban have been planted in the Park and have not yet naturalized. Barberry, winged euonymous, autumn olive, Japanese wisteria, and rugose rose, for example, have proved successful enough that their continued use elsewhere in the Park has been suggested with control of these species confined to areas intended to be more natural in character. However, this does not necessarily mean they will not become pests. The multiflora rose, for example, planted at the Point, now finds limited suitable habitat in the adjacent wooded area of the Ramble, but in the future is more likely to spread into any meadow areas which are developed to increase environmental diversity. Throughout the region, it is a pest of serious proportions. These species should be gradually removed from the woodlands, and not replaced in plantings elsewhere in the park. This list should be periodically reviewed and revised by a task force coordinated by the Natural Resources Group of the New York Parks & Recreation Department. While the need to control exotics is generally recognized, in the past there has not been agreement on an appropriate approach. It is not, for example, remotely feasible or necessarily even desirable to immediately remove all exotic pests from the Park or even the woodland areas. Initial efforts should be concentrated on the most pernicious species, namely knotweed and Norway and sycamore maples. Appropriate broad goals are to keep undisturbed areas free of invasion and, in areas of moderate disturbance, to incrementally remove exotics and replace them with native canopy species. In the most severely disturbed areas, the objective may simply be to contain the exotics, at least for the time being. This approach is not unlike medical triage, which identifies those areas which are beyond assistance, those which do not need assistance, and those which can be helped. Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

18


Even when the need to control invasive vegetation is acknowledged, conflicts arise over the use of herbicides. For most people, the justification for using an herbicide is the perception that this will require less labor. Managers note that it is important not to devote a disproportionate amount of energy to control a few areas if the invasives are busily spreading unchecked elsewhere and if all available labor has been allocated. For others, the most intractable aliens, such as Norway and sycamore maple and Japanese knotweed, seem to be simply uncontrollable without herbicides. There is always the danger, however, which was often voiced, of overreliance on herbicides. In response to these concerns, we recommend the following guidelines should the use of herbicides be considered: 1.

Every effort should be made to minimize the use of herbicides. In some areas, any herbicide use at all may be deemed inappropriate, particularly where wildlife might be jeopardized.

2.

All management which includes herbicide use should follow the Integrated Pest Management (IPM) approach, which advocates combining herbicides with non-chemical procedures to minimize the reliance on herbicides.

3.

Herbicide use should be confined, to the maximum extent possible, to severely invasive exotic species.

4.

Wherever herbicide use is being considered, entirely mechanical non-herbicide procedures should be implemented as well and evaluated for effectiveness.

5.

The initial management should include at least one mechanical clearance before any herbicide is used.

6.

Herbicide use should diminish over time on each site, as initial control is accomplished and more desirable plant communities are established. Where use has remained high for several years, the management program should be reevaluated.

7.

Be consistent and continuous with management. Follow-through is critical. Do not initiate management on an area larger than can be sustained over time. Where prioritization is required, protecting the least disturbed habitats should be given the highest priority.

Whether herbicides are used or not, there will be a large labor demand for mechanical removal of exotics. Virtually all this work is hand labor and must be done with care and adequate supervision. Once a forest management team is in place, their efforts should be augmented by volunteer programs, such as the LIVE (Learning and Involvement for Volunteers in the Environment) student volunteer program. Last year LIVE supplied over 3,800 work hours requiring only 300 staff hours. Exotics removal is also suited for programs involving the handicapped, scouts, and youth training. Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

19


Persistence and patience, not weaponry, is the key to exotics control. What is important is not how hard you hit the target, Qut how often. After all, we are talking about plants that have shown themselves to be favored and spread by disturbance. They are resilient, prolific, and ubiquitous. Feral cat and dogs represent additional problems in the Park and pose a severe hazard to already stressed wildlife populations in the Park. Leash laws should be far mo~e rigorously enforced. There has also been serious concern raised about the spread of several native species in the Park, foremost among them the black cherry (Prunus serotina). The 1982 tree inventory revealed that over 19% of the trees in the Park greater than six inches in diameter were black cherry, and the ratio was far higher if one includes sapling size trees. In the Ramble, for example, the proportion was about 80%! This plant is clearly reproducing aggressively. Some have argued that, in the interest of maintaining diversity, this species should be treated like an invasive exotic. There are, however, some important distinctions. A defining characteristic of an invasive exotic is that native species and often whole native communities are literally displaced. The cherries are not invading healthy and diverse landscapes, such as oak and beech forests. At worst, they are reproducing well on sites which were previously turf or tended beds and establishing dense stands which temporarily occupy the space. In many cases, it is not native species they are crowding out, but exotic disturbance vegetation. Perhaps more importantly, the cherries do not preempt the return to native forest. If the exotics could be kept at bay and adequate seed sources for indigenous plants were available, natural succession would gradually replace the cherries with more diverse native vegetation. In sharp contrast, where Norway maples are established, there is no evidence that native communities would gradually colonize the site, even if the cherries were kept at bay. More than anything else, the cherries are taking advantage of reduced levels of maintenance which permit early successional vegetation to colonize many areas of the Park which were formerly tended. Because disturbance levels are high and there is only limited representation of native habitats in the vicinity, only a few natives, all easy propagators, account for a disproportionate amount of new growth. They represent a greater problem in horticultural landscapes, where they grow like weeds, than they do in the woodlands where their reign will be short-lived if more stable forest cover is established. American elm and black locust are similarly prolific and will also be controlled naturally once more forest-like conditions prevail. This, of course, is the critical distinction. Cherries, elms, and black locusts are easily controlled naturally, that is, by other native vegetation. This is not the case with knotweed and Norway or sycamore maple, which actually control and eliminate native vegetation. For this reason, the cherries and other prolific natives are not a threat to native habitats, but may be viewed as a maintenance problem in horticultural landscapes. Similarly, where they are abundant in woodland areas, it may seem appropriate to remove cherries and replace them with more diverse native vegetation of greater value to wildlife and scenic character. At present, however, this is not a Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

20


recommended course of action, because exotic invasives currently pose a much greater threat. Whenever trees are cut, it is an open invitation to disturbance species to colonize. It is also clear that currently available levels of maintenance are not enough to care for the landscape as it is, much less an increased demand. First priority should be given to stabilization and exotics control. Once this is accomplished, then selective removals accompanied by additional planting can be considered. When a general planting plan is developed, tree species typical of later stages of succession, such as hickories and beech, can be planted to accelerate the natural transition. If this sequence is followed, there is also likely to be support for the Park's efforts from the very people who have opposed such actions in the past. Lastly, when considering exotics, it raises the question of whether or not the woodlands should be perceived of as a native forest or as a crafted forest-like landscape comprised of both exotic and native species. The Ramble was clearly conceived of as the latter by Olmsted, and Hallett was very similar. In contrast, the North End supported some forest at the time of the Park's creation, and more woodland was allowed to succeed naturally than was planted. The major design emphasis was not planting, but reshaping the stream channel to create a sequence of pools and waterfalls, and to establish long vistas and scenic views in this naturally more dramatic topography. Occasionally it is suggested that native species are more vulnerable to urban stresses. Unfortunately, however, the exotics which are held up as successful examples often are invasive, causing problems in planted beds and woodlands alike. While the full breadth of native communities is not sustainable in the city, more than enough species survive to create rich and compelling landscapes if appropriately managed. The wildlife goal is to s~pport as great a diversity as possible of indigenous species which obviously have coevolved with native plant communities. While exotic food sources are also used by wildlife, they do not appear to be necessary to wildlife. During the interviews, there were very strong sentiments expressed in support of the use of native species only in the woodlands. An all-native policy generally is defined as excluding any species introduced in the post-Columbian era. It may, however, be advisable to consider some species which are endemic to analagous habitats slightly further south or which reach their northern limit in northern New Jersey in anticipation of a likely continued warming trend, which is compounded by the urban microclimate. Some species which might be considered include river birch (Betula nigra), Kentucky coffee-tree (Gymnacladus dioica), white fringetree (Chionanthus virginicus), Carolina silverbell (Halesia carolina), cucumber and sweetbay magnolias (Magnolia acuminata, M. virginiana), and redbud (Cercis canadensis). Another consideration is that native plant communities, once established, will be far more self-sustaining than the more maintenance intensive landscapes that characterized Olmsted's era. Exotics, on the other hand, often become pests if they naturalize well and, if they don't reproduce, they fail to support a naturally self-sustaining system and must be tended and replanted. This is not to say that native communities will be maintenance-free, but that the care required is more appropriately described as management, rather than maintenance, and that the Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

21


major activites required will involve repair of damage from use and exotics control than direct horticultural support of the plantings. This is especially important given the realities of the maintenance dollar today and the pressing need for many other maintenance tasks. Despite the evidence that exotics pose such severe threats and cost so much to control, new species are continuously being promoted on a grand scale. A current example is the Sawtooth oak (Quercus acutissima), pushed as potentially valuable for wildlife. It is foolhardy to spread it throughout the landscape and then sit back to see if it naturalizes all too well. Because so little is known about many exotics, it is strongly urged that plantings in the woodlands be largely confined to native species. Where greater diversity is desired, only those exotics which have been used locally for a long enough period to assure their staying within bounds should be considered. Of far greater significance \vould be concentrating such efforts on reintroducing native species, including the new American chestnut crosses which are being developed currently. The most often cited reason to introduce more exotics into the woodland's landscape is to increase diversity; however, until the full repertoire of suitable native species has been used, this is not an adequate rationale. No aesthetic requirement has yet been offered which would make the use of exotics necessary. A number of excellent recommended plant lists have been prepared, the most detailed of ,vhich can be found in the Parks & Recreation Department report, "The Ramble in Central Park, An Historic Landscape Master Plan", and in the "Report on the Birding Areas of the Ramble in Central Park". While these lists reveal a lvealth of predominantly native species which might be implemented over time, there are a few species which are likely to be especially useful in the early stages of woodland restoration. All of them can be found in a wide variety of urban wildlands and have demonstrated a tolerance for the urban environment, if uncontrolled trampling can be checked. Some, also, are more vulnerable to air pollution and should not be planted along major roadways. They should be planted in natural plant community groups keyed to characteristic habitats and in planting patterns that are typically found in the wild. Some species are not widely available commercially but could be obtained by contract propagation or in-house production by the Park. The Greenbelt Native Plant Center is an excellent example of the kind of approach which greatly broadens the Parks & Recreation Department's restoration opportunities. Similarly, the proposed acquisition of the Mohlenhoff Nursery would significantly expand the Park's propogation capacity. Recommended species include: Canopy Trees Red maple Silver maple Sugar maple Yellow birch

(Acer rubrum) (Acer saccharinum) (Acer saccharum) (Betula lutea)

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

22


Pignut hickory Shagbark hickory Mockernut hickory Hackberry Black walnut Tulip poplar Sweetgum Sourgum Whiteoak Scarlet oak Swamp white oak Chestnut oak Black oak Black willow Basswood

(Carya glabra) (Carya ovata) (Carya tomentosa) (Celtis occidentalis) (Juglans nigra) (Liriodendron tulipifera) (Liquidambar styraciflua) (Nyssa sylvatica) (Quercus alba) (Quercus coccinea) (Quercus discolor) (Quercus prinus) (Quercus velutina) (Salix nigra) (Tilia americana)

Small Trees & Understory Trees Serviceberry Gray birch American hornbeam Pagoda dogwood Flowering dogwood Hop hornbeam Sassafras Bladdernut

(Amelanchier canadensis) (Betula populifolia) >I(Carpinus carolina) (Comus alternifolia) (Cornus florida) (Ostrya virginiana) (Sassafras albidum) (Staphlea trifolia)

Shrubs Speckled alder Smooth alder Buttonbush Summersweet Silky dogwood Black huckleberry Winterberry Spicebush Flame azalea Pinxter azalea Swamp azalea Shining sumac Smooth sumac Staghorn sumac American elder Meadow sweet Hardhack Highbush blueberry Lowbush blueberry

(Alnus incana) (Alnus rugosa) (Cephalanthus occidentalis) (Clethra alnifolia) (Cornus amomum) >I(Gaylussacia baccata) (TIex verticillata) (Lindera benzoin) (Rhododendron calendulaceum) (Rododendron nudiflorum) (Rododendron viscosum) (Rhus copallina) (Rhus glabra) (Rhus typhina) (Sambucus canadensis) (Spirea latifolia) >I(Spirea tomentosa) * (Vaccinium corymbosum) * (Vaccinium vacillans)

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

23


Mapleleaf viburnum Arrowwood Nannyberry Northern arrowwood Yellowroot

(Viburnum acerifolium) (Viburnum dentatum) (Viburnumlentago) (Viburnum recognitum) (Xanthorhiza simplicissima)

* Appropriate in open landscapes There has been considerable interest in establishing evergreens, both trees and shrubs, in Central Park. Not only are they aesthetically appealing, but they also supply important winter shelter for wildlife. It is, however, important to note that very few evergreens are indigenous to the native landscape and the bulk of those planted by Olmsted failed to survive. Air pollution, which clogs the leaf's pores, is especially hard on these plants which shed their leaves (needles) only every three or so years rather than after only eight months. Several native species, however, do occur throughout the region and persist in well managed urban wildlands. Hemlock (Tsuga canadensis) is the only shade-tolerant forest canopy species; however, white pine (Pinus strobus) can be established in glades. Broad-leaved evergreens, such as American holly (llex opaca), inkberry (llex glabra), and laurel (Kalmia latifolia), can be established in the forest shrub layer.

Maintenance & Security It is almost unnecessary to state that maintenance and security are inadequate; after

all, this is an urban park. In fact, maintenance and security in Central Park are vastly superior to many other parks in the city. Nonetheless, almost everyone interviewed raised these two issues repeatedly. Not unlike damaging park activities, these problems, though extremely difficult hurdles, must be dealt with successfully if restoration is to be accomplished. Maintenance and security were also frequently yoked. Poor maintenance, it was noted, made people feel less safe and was assumed to foster crime. Similarly, increasing maintenance personnel was often suggested as a preferable means of upgrading security, by providing a 'presence' in the Park, rather than relying exclusively on an increase in policing activities. Maintenance is one of the most frequently discussed issues in park management and perceived of as the most intractable. There is no faster way to get an emphatic negative answer than by requesting a significant increase in a maintenance budget, yet virtually every problem raised in this study is ultimately tied to maintenance. Obviously, if the woodlands had been adequately maintained, there would be no need for wholesale restoration. Yet the willingness of agencies to spend money on new capital projects is matched only by their reluctance to spend it on maintenance. Ironically, such capital projects, once installed, rarely receive the maintenance they require and typically deteriorate rapidly, just another stage in the cycle of construction followed by neglect. This approach will be even less successful in the woodlands if the long-term goal is to establish relatively self-sustaining landscapes and largely native habitats. Even though designers today are urged to plant 'low-maintenance' landscapes, a new landscape needs continuing care especially during the first three-to-five-year establishment period. The temporary success of the Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

24


woodlands if the long-term goal is to establish relatively self-sustaining landscapes and largely native habitats. Even though designers today are urged to plant 'low-maintenance' landscapes, a new landscape needs continuing care especially during the first three-to-five-year establishment period. The temporary success of the recent renovation of the Point in the Ramble is already jeopardized by inadequate maintenance and failure to control destructive use patterns. The difference between a conventional capital project approach and that required for effective long-term landscape management is no less important in the area of fundraising. City capital projects are funded through the sale of bonds and when the city has a good credit rating, monies are relatively easy to secure. Maintenance, on the other hand, is funded through the tax base, which is the problem. It is, however, the clear intent of the Central Park Management and Restoration Plan to maintain what is restored. This goal underlies the Conservancy's current capital campaign to raise a $10-million endowment, using private funds to insure the future. At the same time, the approach to capital projects is evolving. The first few years after a major landscape installation are critical ones, warranting an extra measure of care beyond what will eventually be their annual maintenance, and this cost is increasingly recognized in the capital budget. The Central Park Administration is doing an excellent job of maintaining the areas it has restored. The approach which is advocated in this report is clearly labor intensive regardless of how funding is obtained. Moreover, it is best implemented by individuals who are familiar with the site and have been observing the changes in the landscape over time. There are several existing models within the park system which may be appropriate for management of the woodlands. The first is the specialized team and the second is the caretaker or zone gardener. Despite the difficulties of confronting the labor issue, it is mandatory because good forest management is a lot more like maintenance than a traditional capital project. There are, at present, several specially trained "job-specific" teams in the Park, including playground repair and grafitti removal; they range over the whole park and are specially trained and equipped for their assigned task. The team approach would be as useful in implementing projects and could be coordinated with the Natural Resources Group Natural Areas management crew. Since the tasks are unfamiliar, personnel will benefit greatly from the opportunity to maintain a running dialogue with each other. Because there is no standardized training available in ecologically sound forest management, it will be helpful to conduct on-site workshops and establish a sequence of demonstration areas which are monitored and evaluated, in cooperation with the Natural Resources Group. The techniques demonstrated in Central Park will be applicable throughout the park system. Indeed, like feeding time at the zoo, the restoration effort should be actively publicized and made the focus of tours and walks. Visitors should be informed about the schedule and work sites so they can observe the activites. Temporary moveable exhibits can further inform the visitor and help offset suspicious reactions. In the North End, the restoration work site also will provide a destination in the woodlands which is safer for the visitor because of the crew's presence and can become a significant vehicle for reintroducing the general public to the site. Once Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

25


established, the team could be expanded and coordinated with a variety of existing and proposed programs, including adult education, trade school and youth training programs. A specially trained crew also would be of considerable use elsewhere in Central Park in small wooded areas as well as in larger natural areas in the park system. A more difficult aspect of the team approach to the management crew is recruiting appropriate personnel. Landscape workers are often unsure where they fit in the hierarchy and there may be no appropriate advancement for a qualified worker over time. It is a job which entails hard physical labor and also requires a thoughtful and trained individual, a niche which is often poorly recognized in a bureaucracy. Recruiting from among former rangers, especially seasonal staff, may be fruitful. Turnover is typically high and the most frequent complaint of the rangers interviewed was that they didn't get to spend enough time outside, something easily remedied in woodland management. Each one has already demonstrated an interest in natural history and urban ecology and a degree of personal initiative. Once there is a trained core of individuals, additional labor can be recruited seasonally from LIVE and other volunteer groups with team members leading the crews. The caretaker approach was also considered. However, the current scale of the work involved greatly exceeds what can be effectively implemented by one individual. Currently in Central Park, smaller crews of two or three are being implemented and have provided greater flexibility in resource management. The funding required to support a forest management crew'is considerable, though not when compared with a major capital landscape project. The fact that a crew represents additions to the labor force is probably a greater obstacle than the dollar amount involved. It may be very difficult to obtain the required labor from the Department of Parks & Recreation. It is in this area that the Conservancy has the opportunity to make a profoundly important contribution. The Conservancy's mission, as stated in Rebuilding Central Park: A Management & Restoration Plan is "to act as a catalyst by funding innovative programs and projects that cannot be done with city funds". Two programs integral to woodlands management and restoration merit significant levels of Conservancy support: the Urban Rangers program and a Forest Management Team. The Urban Rangers Program was consistently praised during the interviews and additional rangers were perceived to be a solution to a wide variety of problems, especially security issues. People simply feel safe when there is a Ranger present. Another more subtle aspect behind their effectiveness lies in the Ranger's educational perspective. Activities that are classified as security problems and dealt with as policing matters by security personnel are often perceived as educational issues by the Ranger. One Ranger's response, for example, to an illegal campfire was to engage the picknickers in a dialogue about the hazards of fire near trees and how to put the fire out safely. Similarly, the Rangers are very responsive when approached by Park patrons. They typically take all requests seriously, rather than dismissing some concerns because the activity in question is not specifically illegal or worth a citation. In this manner, they often are able to defuse, rather than escalate, Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

26


potentially difficult situations and keep the major focus on education and interpretation rather than on security. While not a substitute for police and P.E.P. (Park Enforcement Patrol) officers, a greater Ranger presence can make the use of security personnel more efficient. A permanent Ranger station in the Ramble and North Woods were proposed and should be considered; however, it is of greater importance that they be out and about in the woodlands. A pair of Rangers may be required in the North Woods for reasons of safety. Given that only about 50% of a Ranger's time is spent in the field, supplementary staffing may be required to maintain an eight-hour-a-day presence. Lambert Pohner, the famed 'Falconer' of Central Park, for years performed an analagous role in the Ramble, giving impromptu tours and running a virtually continuous monitoring and interpretive program. He introduced many people to the joys of bird watching and can be credited with much of the present popularity and public awareness of the Ramble. He is much missed there today. The idea of permanent Ranger staffing in the North Woods also could be easily coordinated with the proposed North End Discovery Center, which will feature a small museum and workplace. The building area is very limited and would benefit enormously from a comprehensive associated interpretive program in the field, especially with its mandate to do ecological, historical, and cultural research. There is no indication that increasing the number of Rangers can be accomplished with city funds. Even now, the prolonged replacement procedure has resulted in personnel shortages. However, this can be remedied by direct funding of additional Rangers by the Central Park Conservancy above and beyond what is provided by the Department of Parks & Recreation. Today, for example, the Borough of the Bronx pays directly for two extra Rangers from its own budget. In the same manner, the Conservancy should seriously consider independent funding of a Forest Management Team (or teams) to ensure that appropriate management is undertaken without undue delays and on a large enough scale. This effort should augment, rather than replace, the city's responsibility. It is essentialto remember that most of the woodland areas are deteriorating and that this deterioration will accelerate with time. The current restoration goals of the Central Park Administration have sought to achieve complete renovation of the Park by the year 2000. The work of the next generation will be to sustain this effort and will depend on maintenance and management more than anything else. New York, like other cities, is beginning to recognize that renewing and caring for its past accomplishments is critical to fulfilling its present and future needs and opportunities.

Education & Signage Perhaps the greatest long-term opportunity to reduce stress to the Park's woodlands from trampling and misuse of the landscape lies in the educational and public relations programs run by the Central Park Administration and the Parks & Recreation Department. The average individual's interest in environmental issues is growing steadily, as is evidenced in the media. Urban ecology is an ideal topic to Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

27


develop further in programs and publications and would dovetail well with increasing public awareness and acceptance of the restoration efforts. Ecological disturbance and misuse of the Park have understandably not been emphasized during the renewal effort. However, there have been extraordinary changes in the Park in the past few years. People are back in the Park in great numbers. The restoration work funded by both the Conservancy and Parks & Recreation Department is widely appreciated, despite the continued suspicion some people retain toward any change in the Park. Topics which might have been more difficult to raise in the past are much more understood today. This will also facilitate a serious dialogue on park use, both within the Parks & Recreation Department and with the user groups, whose help should be actively solicited. Additional coordination with private efforts, such as the birdwatchers tours, would greatly enhance Park-sponsored efforts to develop a comprehensive presentation to the public. The long-term sustenance of native habitats in the urban environment will require not only effective management, but also greater sensitivity and awareness in the public, which are best fostered by education, and with every age group. Building respect for the Park through restoration and good maintenance and engendering responsibility in the patron through consistent education have been fundamental to the Central Park Administration's efforts since its inception. The existing publications and programs run out of the Dairy and the Castle and in the schoolrooms focus primarily on discovering the wonders of the Park itself, its history and the activities offered there. The tone is very positive and covers a diverse array of topics. Direct, firsthand, concrete experience of the Park are seen as the foundation for building an understanding of natural phenomena. Program leaders have found that it takes time for children to learn, to think, and to change their attitudes and actions. Therefore, the current curriculum consists of two to eight contacts in the classroom and in the park, working in small groups with three staff persons working with each class. In addition to the more in-qepth programs currently in operation, a simpler shorter program which focuses exclusively on the appropriate use of the Park was proposed which reaches the widest possible audience, not unlike a typical single school group visit to a museum. A significant aspect of education is signage, about which there are many contradictory opinions. The opinions of at least some park users are clear: some new signs are vandalized almost the moment they are installed. Most caretakers, however, feel the need for more comprehensive signage. For policing personnel, adequate signage permits more effective enforcement and can mean the difference between issuing a citation and a warning. One of the more frequently asked questions, for example, concerned where bicycle use is permitted. Signage, of course, can be informative and attractive as well as simply intrusive. The new exhibit signage in the park, for example, is already more successful and attractive than in most other parks. It was generally agreed that park-wide regulations should be displayed at all park entrances in conjunction with guide maps. Additional interpretive signage can be used in the woodland areas, Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

28


contributing to the education of the users and describing how fragile the natural habitat areas are. Interpretive trails in the woodland areas, especially in the Ramble and the North Woods, would inform even the casual visitor about urban ecology, landscape management, and habitat restoration. The Central Park Administration is in a position to make a unique contribution in the field of outdoor interpretive signage, which is at present an art still in its infancy, too often limited to numbered plant identifications and simplistic trail markers.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

29


The Approach & Frarnework of the Landscape Management & Restoration Program The most significant obstacle to woodland restoration in Central Park has been the difficulty of finding an approach which reconciles the seemingly conflicting needs of the various interest groups, especially between those interested primarily in aesthetics and design, who desire a complete historic restoration, and those who view these sites as significant natural habitat and seek to avoid any disruption of the current habitat. Even when the Parks & Recreation Department has made a concerted effort to address habitat concerns and limit disturbance of vegetation while restoring the historic landscape features, there has been strong public objection. The proposed restoration of the Loch and its associated architectural features, for example, was stifled as soon as a proposed scope was developed. The proposed plan was undoubtedly misunderstood, but because no effective dialogue was possible, no process of assessment and modification could be undertaken. In past debates over management of the woodlands, it has been frequently posited, especially as concerns the Ramble, that were Olmsted alive today he would not necessarily seek a strict replication of his original design. It seems, however, equally likely that he would maintain a strong sense of design and seek to restore critical vistas, diverse habitats, a rich aesthetic character, and an integral relationship with the rest of Central Park. It is also no less likely that Olmsted would place far greater value on the habitat aspects of the Park, especially given the changes that have occurred in the region since the Park's creation. It is appropriate to seek to restore the historic landscape features in the three woodland areas, but only to the extent that doing so is consistent with preservation of their natural habitat and woodland character. These goals are not in conflict with a managed native landscape. More recently than Olmsted, Russel Wright, at his horne and greatest work, Dragon Rock, now known as Manitoga, displayed exactly this design aesthetic, albeit in a more natural setting than Central Park. During the interviews, it became apparent that the conflict here lies less with the goals of the work and more with the process of implementing the goals. The woodlands restoration and management has been held up by the lack of a consensus on how to proceed, not by any anticipated funding problems. The naturalists highly value the scenic aspects of the Ramble and other woodland areas, and are aware of the profound need for rebuilding the infrastructure. Similarly, those who speak for the historic design have a strong desire to establish native plant communities and halt the continuous deterioration of the woodlands. The real problem seems to lie in the idea that 'restoration' can be accomplished as a discrete project, with a short construction time of one year or less, analagous to other reconstruction projects in the Park, such as the Sheep Meadow or a section of the Park's perimeter, which can be very destructive to remnant habitats. Such an approach, by definition, concentrates site disturbance, involving removal of large amounts of vegetation all at once before initiating replanting and stabilization. Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

30


A larger project, constructed in the way capital projects usually are, which includes architectural reconstruction, may span several seasons, during which time nearly all valued wildlife is displaced from the site. The Ramble, for example, which is a temporary resting site for migratory warblers crossing the vast urban wasteland may be irreplaceable in the region. Even a project affecting only a portion of the site may deny critical habitat to these birds who cannot wait out a one-or-two year hiatus. Struggling natural vegetation is similarly impacted. When forest restoration is viewed in the spirit of a capital project, the sheer amount of work undertaken becomes a severe stress to fragile remnant systems. Large-scale grading operations, extensive soil reworking, and massive planting efforts are, in this perspective, sources of disturbance and should be undertaken only where the landscape is in collapse, completely overwhelmed by knotweed, or with extensive and severe erosion. Similarly, where the vegetation is a mix of desirable species and pests, complete elimination of all invasives at once may actually open up the landscape so much that a reinvasion, perhaps even greater in scale than before, is invited. This habit of "V holesale reconstruction is poorly suited to forest restoration. Forests themselves take a long time to develop. This approach also requires that the designer must make many assumptions about the site with very little information. Trees, for example, are routinely.evaluated and only healthy specimens preserved, yet in a natural landscape many misshapen trees are the norm, and every stage from birth to mortality is found. . A common approach to dealing with these problems is fragmenting a project into smaller capital reconstruction pieces. However, though this confines damage to more limited areas at one time, it does not address the fact that this is simply a stressful way of working, and antithetical to establishing healthier, more self-sustaining natural systems. Another difficult aspect of restoration to comprehend, and the reason behind many unsuccessful capital projects, is the assumption that a complex living system can simply be installed in a season or two and then requires only maintenance. This misperception also lies behind the idea that a detailed comprehensive plan should, or even can, be developed before any restoration is initiated. Effective restoration should be carried out over decades. Many sensitive species should not be planted until greater levels of stability have been achieved. In some areas this will take many years because native canopy and understory layers need to be established before enhancement of more fragile groundlayer vegetation can be undertaken. Elsewhere it is impossible to assess the potential of natural recovery processes until the destructive impacts of misuse and exotics are controlled~ This is especially true in the North End where reproduction of native speices is still locally vigorous and may prove in some areas to minimize the need for replanting if competition from exotics can be reduced. Restoring a landscape is quite like raising a child; you can't really do it all at once or even plan for it all at once. This appraisal, however, should not be taken to mean no planning is necessary, only that a continuing planning process, with assessment and revision over time, is more realistic than a fixed

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

31


comprehensive plan. Long-term goals for each area must be reviewed and agreed upon in concept and a comprehensive plan developed for each set of management actions before they are initiated. The overall process must be clear even if every detail of every stage is not yet fully worked out. An incremental design and implementation process should proceed holistically. A good analogy is the holograph, which is from the same root word. A holographic image, such as the chessboard figures of Star Wars, has depth and is more realistic than a two-dimensional figure. When a holographic negative is cut in half, each piece bears a whole image, but with slightly less detail. No matter how small and how many pieces, the image is always whole. This process of landscape restoration is like putting the pieces of a cut negative back together again, making it whole once more. Each stage of the design process must be whole, but a greater level of detail will emerge at each level. The implementation process, and later the management process, should be as incremental as each preceding step. Tree pruning, without concurrent trash removal, will go unseen by the public and miss the opportunity to . involve visitors more directly in the restoration process. And, of course, it is participatory because those who have a hand in using and caring for the landscape surely must have a hand in designing the place. This is a team approach at every level. This process flows rather than proceeding from one discreet phase to the next, and the broad cast of participants changes subtly in composjtion over time, affording both continuity and freshness. This recommended, incremental process for design and implementation seeks to achieve restoration in phases and represents levels of health of the system, instead of area-by-area project completion. An important key to this approach to restoration is the principle of "minimal intervention", that is, taking only those actions which are necessary to counteract disturbance, but'also taking no actions which may inhibit the natural processes of restoration. The design process is informed by the changes observed during the implementation process. For example, this report has already clearly identified dirt bikes as a source of stress. This problem can and should be addressed immediately. It does not need to wait until construction documents are drawn up and reviewed. Similarly, eroded areas can and should be stabilized and will not preempt any critical design decisions, and the spread of knotweed can and should be checked. It is important that this incremental approach not be confused with the piecemeal

process typical of the past. And no action should be initiated without appropriate follow-through, most particularly ongoing management and maintenance. The following describes a general restoration scenario appropriate for Central Park:

Overall Progrmn and Policy Statement This report, Landscape Management and Restoration Program for the Woodlands of Central Park, is a document which represents the work of this phase. The first Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

32


priority, from an administrative perspective, is to initiate programs to control those stresses which were identified, including bikes, vehicles, and dogs. In addition, two management priorities are recommended for the forest management team. First, exotics removal in the Ramble and the North Woods should concentrate on knotweed and Norway and sycamore maple seedlings and young sprouts in those areas where they are invading and becoming established, rather than in areas where they are fully entrenched. Second, erosion control should focus on stabilizing areas of exposed bare soil. The team should be trained in mechanical control of exotics and it is advisable if one'team member is trained and licensed in the application of herbicides, although this is not absolutely necessary. At the same time, the team will require training in stabilization techniques, including long straw, jute matting, and dead stout stakes, as well as bioengineering techniques of live stakes, fascines, and brush layering. Replanting should be confined to the ground layer, where there is no vegetation at present, using vegetative plugs of little bluestem, for example, in open landscapes and lowbush blueberry in areas which, though temporarily open due to erosion, will gradually close over time. Where bare ground has been so eroded that the addition of soil is required, it is usually not necessary to incorporate new material deeply into the existing soil. Where the surface has been compacted, however, it is mandatory to break up the compacted layer completely. Otherwise is an impermeable membrane between old and new soil, preventing roots from growing upward into the new soil and inhibiting water infiltration from above; the new soil and new plantings will never properly knit with the existing soil, leaving the site permanently less stable than was the goal. Because there are no viable roots in tightly packed soil, the risk of disturbance is very low. This layer may only be inches thick, and there is rarely a need to go deeper. Hand excavation and raking are the most appropriate methods for this task. At this point, organic matter and other soil amendments can be added, and if necessary additional topsoil added to reestablish the original grade. In other situations, mulch and seed, or sod would complete renovation. However, this is not the case in the woodlands. Because of the heavy canopy, vegetative recovery is very slow. Reproduction by seed is negligible and vegetatively established plants may take several years to provide adequate cover under dense shade. Therefore, additional protection in the form of an erosion-control blanket is usually beneficial. A three-inch layer of long straw (that is, uncut rather than shredded) covered with jute matting tacked with wooden stakes is a completely organic treatment which provides erosion control as well as a measure of protection from damage should some trampling occur. Jute matting alone is not adequate. When the soil surface is treated in this fashion, uncomposted leaves may be used as an organic amendment without worrying that they will induce slippage of the new soil. Both the leaves and the matting with straw will decompose in place, providing additional nutrients. This technique is durable enough that the surface will withstand significant levels of runoff and disturbance and can be effectively implemented before complete reconstruction of drainage structures.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

33


Exotics control should be carried out concurrently and incrementally -- a kind of continuous attack policy. Any area cleared should be replanted immediately, with straw and jute matting wherever existing native cover is inadequate to close the gap in a single growing season. No greater area should be opened and replanted than can be adequately maintained in subsequent years. Erosion control and exotics control should be the only major priorities until a much greater degree of stability is achieved throughout the woodlands. At the Hallett Nature Sanctuary, the only immediate priority should be controlling unwarranted use of the site by closing access at the pond edge. This will also serve to restrict access by feral cats and dogs which has impacted wildlife in the past. Control of erosion and exotics is not as critical here as it is in the Ramble and North Woods.

Conceptual Plan for the Woodlands The activities of this phase would include: (a) Site evaluation and inventory review (b) Conceptual design (c) Management areas plan and interim management program There has been a remarkable amount of data gathered over time on the Central Park Woodlands, ranging from avid birdwatchers' life lists to scientific vegetation surveys. This information, though disparate, could provide a comprehensive picture of the woodlands' past and clarify current inventory gaps. This data should be integrated and mapped on an up-to-date topographic base. An Existing Conditions Map should also be prepared which describes existing habitat and the extent of disturbance. A concurrent effort should be made to gather and coordinate all historic design information and evaluate existing and future infrastructure needs. An historic landscape architectural study should be undertaken, probably by Central Park staff, including photographs, plans, sketches, and other archival materials. A significant amount of natural and aesthetic information has already been gathered for the Ramble in a report entitled, "The Ramble in Central Park: An Historic Landscape Master Plan", prepared for the New York City Department of Parks & Recreation. Preliminary design documentation should be initiated in this phase. Architectural features to be reconstructed should be identified as well as conceptual path layouts, including widths, materials, and any modifications to the historic design. Vistas and scenic panoramas should be delineated as well as critical sight lines. No cutting, however, should be undertaken at this time. This is not to say that vista restoration is altogether inappropriate, it is merely untimely and should be postponed until plant communities are both more diverse and more stable and confined to those sites where habitat values will not be compromised. In the meantime, restoration efforts can be directed to prepare the site for eventual vista reopening. Obviously, no new canopy should be planted along view lines, but desirable low shrub vegetation can be established. Landscape character should also be described, with clear distinctions made between open and closed canopy landscapes. Open landscapes are those stabilized primarily with herbaceous vegetation and may Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

34


include turf, tall grass, and wildflower meadows. Occasional trees, either specimen or groves, as well as shrub thickets may be included. The woodlands are, by definition, closed landscapes and should be stabilized primarily by stratified woody vegetation with nearly continuous canopy cover. Understory, shrub, and groundlayer vegetation is rarely continuous, except in patches. Open landscapes should be limited in the woodlands and confined to a few open glades, path margins, and transition zones along woodland edges. The existing and proposed plant community types should be described and keyed to a phased management plan which identifies generic management zones and guidelines. This preliminary design should provide enough direction to permit significant management and restoration to be accomplished while more detailed design development is in progress. A conceptual plan should be developed which describes the major habitats proposed, the design character, and major infrastructure restoration.

Phased Project Implementation Program The program and scopes for a continuing sequence of projects should be delineated, including capital projects, ongoing maintenance and staffing needs, and projected costs. During the time it takes to complete design documentation and fund these projects, the-major direction of restoration should be to prepare the woodlands to better cope with the impacts of construction. Where new pathways are proposed, they should be laid out for evaluation and modified in the field as necessary. Large trees along the route may benefit from root pruning as well as a prophylactic canopy pruning to compensate for projected root losses, once the comprehensive plan has been appropriately reviewed and accepted. Critically ill people in need of surgery often must wait until they have recovered acceptably to be strong enough to face the hardships of surgery. An analagous situation is faced in the woodlands. The 'surgery' these landscapes require -rebuilding the infrastructure -- will be stressful. New paths are urgently needed, drainage must be controlled, and bridges and archways need reconstruction. These activities, while stressful, cannot be avoided if the landscapes are to be utilized without damage by Park visitors. But before this is undertaken, the woodlands' recovery must be initiated and more comprehensive planning completed. The margins of all existing and proposed pathways and other features to be reconstructed should be the special focus of exotics control to reduce the presence of invasives available for recolonizing the site. Every effort should be made to avoid unnecessary soil disturbance, such as grubbing and rototilling. These methods may be appropriate for renovating horticultural bed plantings, but are not suited to the woodlands. If the surface is presently stable, even if supporting only exotic invasives, beneath the soil there are roots of numerous different pla~ts often from a great distance away. Tree roots, for example, are completely opportunistic, seeking any favorable ground, and easily extend thirty or more feet beyond the furthest reach of Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

35


their branches. Grubbing and rototilling also disrupts fragile microorganisms and may impact the mycorrhyzae on which good forest growth depends. A task force, coordinated by the Central Park Administrator, is recommended to ensure and oversee continuation of the design as a participatory process. The task force would also be responsible for developing an annual monitoring and evaluation process and establishing demonstration areas for all new techniques and products under consideration. The size of the task force should be limited to no more than eight people, but could be augmented by continued interviews and reviews with interested parties. Ideally, the proposed forest management team should be in place and have a representative on the task force. Their participation in this phase will serve as a critical learning process. Similarly, the initiation of more extensive management in the woodlands will provide valuable demonstration areas to inform the task force and other park personnel.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

36


Assessment of Current Conditions & Initial Program Recommendations

The North Woods More than anywhere else in the park, the North End offers the visitor the opportunity to experience a natural forest environment. The woodland area is extensive, covering approximately 90 acres, permitting the walker a long journey with minimal intrusion from the surrounding city. Although subject to significant modification during the Park's construction, there are also large areas of original topography which supported second growth forest at the time of the park's creation, especially on the side slopes of the Ravine and Loch. Here we find a native landscape with lower levels of disturbance than are found in any other woodland area in the park. Elsewhere, especially at its edges, the vegetation is similar to the woodlands of the Hallett Sanctuary and the Ramble, a mixture of native volunteers, overgrown plantings, and invasive exotics. When the park was established, the center of Manhattan was several miles to the south of the park. The Greensward Plan, however, was far reaching and reflected Olmsted and Vaux's conviction that the city would soon grow up around the park. Nonetheless, most of the park's visitors entered from the South End and it was there that the major features were concentrated. Even today, the South End is far more heavily used and attracts visitors from a wide array of neighborhoods around the city. In contrast, the North End is far less used, primarily by people from the immediate community. Unlike the Ramble and the Hallett Sanctuary, these woodlands are not even named, and are usually denoted simply as the "North End", even though this area includes the Meer and many other park features. In this report, the name "North Woods" is used to distinguish these forests from the general area of the North End of the park. The lack of named places (the water features are notable exceptions) in the North Woods speaks to the fact that the vision for this area has never been as strong as elsewhere in the park. The site was wilder and more natural than anywhere else in the park at its inception and has simply gone wilder since then. Today this is the area's greatest asset, what sets it apart from the rest of Central Park. This essential quality of wildness, more than anything else, was valued by those interviewed. Upon occasion, in fact, it has been zealously defended. Recently, the Department of Parks & Recreation prepared a schematic plan for the Restoration of the Loch Water Bodies and Adjacent Landscape. While the major effort was concentrated on the water bodies and architectural features, three tiers of landscape restoration were designated. These ranged from natural sites, where only eroded areas would be replanted, to areas selected for thinning, with new ground-cover plantings and vista restorations, and lastly to areas selected for intensive thinning and replanting, according to historic documentation, intended to replicate the original character.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

37


This plan would have represented the first major infusion of restoration monies into the North End, but was vigorously objected to by the community, largely on the grounds that it would have represented too great a change from the existing condition. It was feared the restoration would make the place too open, too civilized, and, as was oft repeated, too much like the South End. The specific details of the plan were overshadowed by the fear of what restoration might mean. A related concern was that, once restored, the woodland would somehow be taken from the community, pre-empted by other user groups. The present percentage of visitors who are neighborhood residents in the North End is over 50% as contrasted with approximately 10% in the south. Their concerns were echoed by area naturalists who feared excessive habitat disturbance. The question "What is restoration?" was frequently asked and many proposed "preservation" as a preferred alternative to restoration. The North Woods today is also cherished for the very lack of identity and care that left it unnamed. It is perceived as the only truly natural area in the park, Manhattan's version of a national park. Indeed, one user even suggested arrowhead shaped signs. More than anything else, people want to see Rangers -- "lots of them" -in the North Woods, to protect it and to protect them. While existing levels of use may not seem to warrant such an investment, no appropriate use, or restoration, of this important resource will be possible until such a commitment is made. Security in the North Woods is a major problem, both real and perceived. Because of the difficulty of getting around in the woods and in this terrain, the only regularly patrolled sites are the Great Hill, Lasker Pool, and the Blockhouse, and patrols go in pairs and in vehicles. Major community use in the North End is limited to peak hours and good weather when there are large numbers of visitors and safety in numbers. Woodland use, however, is lower, often confined to edges, spilling over from the Great Hill, East Meadow, or the Harlem Meer areas. The opening of the Lasker Pool also led to increased circulation through the woods. Once the Meer renovation is completed, it is expected to bring new patrons to the North Woods and may lead to greater criminal activity unless security is dealt with more satisfactorily. Off-season and off-hour activities in the woodlands are often undesirable. Not only is security an issue, but serious damage is inflicted on the park. Night use by dirt bikes is very heavy and especially difficult to control in the woods. As noted earlier, several outlaw trails have been incised into the easily erodible soil on steep slopes by the rocky outcrops just recently. The opportunities for access are many here making control especially difficult in the North End. Some joy-riding and parking in cars goes unchecked at night, according to police. Though relatively quiet during the day, drug-related activites are high at night. Because of the nature of night use, it was often suggested that no effort be made to install lighting in this woodland, which would encourage greater use after dark. This is also consistent with the nature preserve perception of the North Woods. Use'by the homeless is very heavy and several encampment sites have been severely trampled. In one area, for example, a broken city water pipe in the North End near the Loch provided a source of fresh water and supported a large adjacent population. Because there is so much cover in the woodlands, these people can Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

38


remain largely unseen, and uncounted and probably are more able to avoid the patrols which seek to clean up after the homeless at least once a day. Again, it should be reiterated that the park can take a far more active role in assuring better support services for the homeless beyond the park's boundaries. Until more satisfactory and convenient facilities and shelters are provided, life in the park is cleaner, safer, and often preferable to .life on the street. Day-to-day maintenance is especially lacking in the North End. Clean-up and general repairs are dismally wanting from 97th Street and Central Park West to 110th Street. Fallen trees often block paths for extended periods not incidently leading to trampling as visitors walk around them. The bridges are also in dire need of repair. Despite security and maintenance problems, however, interest in the North End is increasing. The Ranger's tours in the woodlands are very popular and a growing number of people are being introduced to this area from the scheduled Thursday bus tours. For most people, it is the sheer expanse of the forest and the extraordinary sense of removal from the city that makes the North Woods so special. As the Conservancy report, Rebuilding Central Park: A Management and Restoration Plan, noted, in the Ravine the visitor feels "transported to the Adirondacks". It is here, and only here, that there can be found a remnant forest in Central Park. Olmsted and Vaux found a second-growth forest on the naturally dramatic terrain of the North Woods and left much of it undisturbed by park construction. As a result, the landscape today is very different from that found in the Hallett Nature Sanctuary or the Ramble. Although there was a significant amount of planting, most of the volunteer vegetation today is native, except for Norway and sycam~re maple and, in the formerly open grassy areas, knotweed. While the North Woods sprawl over about 90 acres, the forest is intermittent and broken by grassy areas, such as the Great Hill and the East Meadow, and several other areas which have gradually closed in over time. The most critical section is the unbroken block of forest, over 55 acres in size, which is centered in the Ravine. It is the only continuously forested area in the park which is large enough to permit management for a wide spectrum of native plants and animals. However, the entire 90-acre area should be managed as a single unit, grading from open meadow and successional woodlands to mature forest, to foster a wide array of native habitats. The central forest area should be maintained with as little disruption as possible and managed to favor mature forest communities. Very little management is required beyond limited exotics removal and occasional canopy replacement. Earlier recommendations to thin the canopy and plant a dense shrub layer are inappropriate here and should be reserved for the more successional woodland margins. Recent management initiatives at the Great Hill, for example, illustrate excellent edge management. With the removal of the dead elms and release of some turf areas, wildflower meadows are becoming established on the upper slopes, bordered by open woodlands lower down. Such long, gradual transitions provide an ideal edge to the area of mature forest. In addition, this management has significantly improved scenic character and restored some of the views and sense of openness which occurred historically at Great Hill. One of the most important tasks in the North Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

39


Woods will be to delineate the recommended pattern of forest, woodland, woody old field, and wildflower meadow which maximizes habitat opportunities. This will also establish a gradient of management on a continuum from the intensely maintained lawn to meadow areas mown annually to woodlands and forest where only limited management is undertaken. Consideration should also be given to the historic landscape pattern. The native trees which comprise the bulk of the mature forest area can be displayed as specimens and in groves in the successional landscapes, and many of the shrubs which were earlier proposed for forest planting will find more suitable habitat in the woody old fields at the forest's edge. The existing path system is largely unchanged from the 1868 design, although it is in a state of disrepair. In addition, there are numerous outlaw trails, all of which are eroding on the thin-soiled steep slopes. The incidence of dirt biking has been increasing recently, especially on the rocky outcrops in the northwest corner of the park where several new trails were cut just this season. This is a severe problem which must be dealt with immediately through more vigorous enforcement and surveillance. The present path design, though historically accurate, presents several major obstacles to the future use of these woodlands. Originally designed exclusively for pedestrians, the narrow paths and several sections with stairs prevent adequate vehicular access for maintenance and security. While it is often assumed that bicycle and moped access exist in this area, this not the case. Stairways, in particular, are obstacles which bicyclists go around, eroding and compacting wide loop trails before rejoining the path. The issue of vehicular access is very controversial. Clearly, in an ideal situation, no vehicular access should be permitted to mar the natural character of the site. Reality, however, offers several very compelling arguments in favor of better access. Effective management of the vegetation and the repair of eroded damaged areas will require some vehicular access which should preferably be concentrated on a permanent trail rather than diffused across the larger site. A width of at least eight feet is required to permit access of the smaller scale vehicles which are suited for use in woodland areas. Access could easily be restricted to 3/4-ton pick-ups. This would, in most areas, require no change in most of the original trail system, only restoration. The removal of the steps will be difficult in this terrain and may necessitate some grading modifications to the design of the paths. Similarly, the entrances to the paths from the drives and sharp curves may also require some revision. Not all the paths would need to be modified, since only one vehicular path traversing each of the major woodland sections is needed. The remaining pedestrian paths, including those on terrain too steep for reasonable vehicular access, would be restored to their historic character, including the dramatic approach through the rocks to the Block House from the north. Some additional reinforcement of a few sites adjacent to the pedestrian paths is also suggested to eliminate off-trail damages by tour groups seeking to reach outcrops and the water's edge.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

40


Another controversial aspect of vehicular access is the issue of security. While many people expressed the desire to see more patrolling on foot in the North End, especially in the woodland areas, this is unlikely to be realized, particularly at night. At the present time, the woodland areas are almost entirely without surveillance simply because they are so inaccessible. Increasing the use of all-terrain vehicles is not an answer. The damage they can inflict on a landscape is all too well documented. The vehicle-accessible pedestrian path loop would permit regular patrolling and a more secure woodland journey. As new visitors use the path and feel safer, they will begin to explore more remote areas. This trail would also accommodate wheelchair access. A similar system is used in Philadelphia's Wissahickon Park, a 2,OOO-acre park in a forested stream valley which is remarkably safe and used by a great diversity of people. Forbidden Drive, forbidden to all except police and park vehicles, runs along one side of the stream and accommodates the bulk of park pedestrian use. A complete review of the path system and broad public participation is needed, however, for there is no clear agreement on this issue. In commenting on the draft of this report, for example, the New york Audubon Society stated that "the argument for an eight foot wide path in the North End is simply not compelling." Some strong sentiments against path restoration have also been expressed in the past. It is seen as a 'wedge' of civilization that will diminish the essential quality of wildness and serve to remake the North End more like the South End. Natural areas, some have contended, should be left alone. However, in recent years, these opinions have diminished as the price of benign neglect becomes more apparent. Without an adequate path system, all access is damaging. It is not necessary to get everywhere in the woods but, rather, to have access enough to maintain a single safe trail. A hierarchical system which includes a vehicular and pedestrian trail, a pedestrian-only path network, and a few complementary adventure trails will provide both access and protection, as long as reasonable levels of enforcement can be sustained. This includes adequate control of vehicles, both private and those related to park uses; bicycles, which are presently very problematic; and pedestrians. As use of the North End increases, and it inevitably will, the path system will also help to concentrate that use to minimize undue pressure on other areas supporting species favored by less contact with human beings. At the same time, a healthy native forest will seem more removed from civilization than a degraded woodland filled with the same invasive exotics that have colonized every scrap of bare ground in the city. No less controversial is any proposed restoration of the water features, including the Pool and the Loch in the Ravine and the Lily Pond below the Block House. Even degraded water features may attract relatively large numbers of wildlife, as compared with surrounding areas, and are consequently still highly valued despite deterioration. Also, the restoration of a filled-in pool entails silt removal, usually by dredging, which is a very disruptive process, displacing both vegetation and wildlife, at least temporarily. The most compelling argument in favor of restoration, however, is the level of recovery possible if the restoration of a water feature is well Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

41


designed and implemented. A remarkable variety of habitats can be established in what is now a site very uniform in character. Because the original stream, Montayne's Rivulet, was much smaller, its flow was augmented by collected stormwater as well as overflow from the reservoir. This has in the past caused problems, delivering excessive loads of silt which gradually filled the Loch; however, if adequate controls, including weirs and sediment traps, are built into a new comprehensive water management system and adequately maintained thereafter, the use of stormwater runoff will be a useful augmentation. Restoration should proceed in phases, beginning at the top of the watershed. Interim stormwater management plans are also necessary to avoid erosion and sedimentation during construction. Special attention should be given to all swales and water bodies, including the Meer. The sequence of cascades and pools built into the original design make it especially easy to break the project into hydrologically discrete units. Runoff from the North Meadow ballfields comprises a significant amount of the stormwater component. Renovation of the ballfields ideally should be completed before initiating work on the Pool and the Loch. Concurrently, the bridges, stone arches, and other architectural features should be restored. As noted earlier, it is critical to have full hydrologic monitoring of this site prior to redesign as it is very unlikely that the original design is adequately sized to support today's rates of runoff. Restoration of the historic structure will require additional stormwater management facilities. Water quality issues should also be evaluated, at both point and non-point sources, and include any fertilizers and pesticides being used in the park.

Initial Program Recommendations for the North Woods 1.

Initial exotics control, concentrating on sapling-size Norway and sycamore maple and knotweed, where they are invading or not yet fully ~ntrenched. No large tree removals are recommended at this time.

2.

Develop a comprehensive hydrologic monitoring and stormwater management program of the whole watershed, including areas outside the North Woods, such as the North Meadow. Potential impacts from Lasker Rink must be reconciled.

3.

Develop a North Woods Ranger Program.

4.

Stabilize all bare soil areas.

5.

Develop a North Woods Base Map, including topography, existing features, and plant community types.

6.

Complete the documentation of the historic design and character.

7.

Develop a generic Management Map and long-term Schematic Design Plan.

8.

Complete the design documentation for the reconstruction of paths, architectural features, drainage infrastructure, and water features.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

42


9.

Initiate phased reconstruction and phased replanting where disturbance is occurring.

10.

Initiate habitat enrichment and wildlife management.

11.

Begin underplanting transitional forests with species characteristic of later stages of succession.

Pho:asc One: Landscape Mo:anagemenl &. Restoration Program for the Woodlands of Central Park

43


The Ran1ble The Ramble, more than any other woodland in Central Park, illustrates the need for ongoing management and maintenance. It is, by all accounts, a remarkable landscape filled with complexities and contradictions that make it especially difficult to deal with. Olmsted devoted more time and attention to the Ramble than any other feature in the park to create one of the finest expressions of the Victorian Romantic landscape. After decades of neglect and intensive use, its original character still prevails, although it is very degraded. As a habitat, the Ramble is deteriorating and urgently needs long-term attention and restoration. Today the Ramble is probably most noted as one of the best birding areas within a 50-mile radius of the city, especially remarkable for the more than 200 species of migratory birds which use the site seasonally. Its location at the center of the parJ< and adjacent to a small lake is ideal. The city, which for migrating birds is like a desert or an ocean to cross, offers very few options for resting and refueling. Greater numbers of birds depend on the Ramble, because there are no alternatives available. As a habitat, the Ramble is indispensable. The Ramble was originally designed as a highly stylized imitation of a natural forest, contrived to offer a broad range of habitats from upland to lowland, cave, cove, and wetland, compressed into a very small site. Conceived as an 'American Garden', the Ramble was a showcase for a wide array of native woodland species, as w~ll as for a variety of then popular exotics. This landscape is both intricate and diverse, especially when contrasted with the turf, shrub banks, and specimen trees which characterize much of the rest of the park, making it more attractive to wildlife. Thus, despite significant deterioration, the Ramble still provides the best habitat available. Wildlife is abundant and even more important to many, easily visible from the many trails which crisscross the site. Without future management and greater visitor control, however, the vegetation of the Ramble will continue to decline and may become relatively useless to wildlife despite the Ramble's many other attractions. Its aesthetic character is similarly threatened by the prospect of complete loss. The Ramble is also more fragile than an analagous native landscape because so much of it was artificially created and is not characterized by a host of complementary natural processes. The steep grades found throughout the site would be difficult to sustain under natural conditions. They are even more difficult to hold as filled slopes, without the support of underlying bedrock, typical in so steep a terrain. When subjected to trampling and bike use, these homogeneous soils easily collapse and erode. Even after 100 years of vegetative cover, once exposed, they rapidly fail. While refilling gullies, adding organic matter, and loosening compacted surface soil is necessary for stabilization, it may not be advisable to restore the original grades everywhere. The current terrain is, in most areas, steep enough to achieve the desired dramatic effect. The illusion of additional height can also be achieved with selected planting. Lowbush blueberry, for example, is a dense low Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

44


shrub that typically grows on ridge tops and steep mineral slopes throughout the piedmont and would be ideal for this purpose and well suited to the now more open eroded banks. Many of the remaining specimens of native trees and other valuable vegetation are very old and now decrepit, with the exception of the Point which was recently renovated. The rich, more complexly layered landscape of the past is being gradually replaced by a more uniform one of continuous knotweed, cherry saplings, and aged trees and shrubs. Diversity of plant forms is as important to wildlife as diversity of species and determines the kind of shelter available. When the Point was restored, for example, it immediately became a birding 'hot spot', illustrating the importance of landscape renewal. Some decline has occurred subsequently, largely due to the nature of the established cycle of capital infusion, followed by inadequate maintenance. Severe trampling is also going on unchecked, as it turned out to be completely unrealistic to assume that access could be controlled. The fence, because it suggests privacy, is actually an invitation and there are no paths to accommodate the walkers who manage to get in, so they trample indiscriminately. If the diversity and plentitude of wildlife is the most significant aspect of the Ramble

today, when the park was opened, it was noted for its extraordinary romantic design. Today, the original character is glimpsed in the still picturesque setting and evoked by the remnant artifacts, especially the bridges. The goal is clearly to match the vision, both functional and artistic, of the Ramble in the nineteenth century. The challenge today is to meet the aesthetic standard historically established and, at the same time, the ecological standard that is being established now. The same passion for landscape composition that characterized the original design is appropriate, although the plant palette should be altered to favor a greater diversity of native species. Earlier design concepts, such as using darker and lighter shrubs to create the illusion of depth, need not be lost in the renewal. It is the spirit and quality of the Olmsted and Vaux design that should be honored, rather than a strict replication of transient landscape features. The Ramble, in part because of its complex design, will require especially comprehensive documentation during the restoration process. Inventory maps should be prepared first which map all existing vegetation by layer; that is, the canopy layer, the shrub and understory layers, and the ground layer. The species spread and caliper of all major canopy trees and specimens should be identified. Generic management units should be identified and a five-year management program identified, with the previously noted priorities: control of exotics where they are spreading and ground stabilization. Concurrently, the original design concept should also be documented, indicating the planting patterns characteristic of each area and the nature of the.stratification of vegetation. Open glades and dells should be noted as well as areas of closed forest. The vistas, overlooks, and scenic character should also be described. It is important to state that this map is intended to record historic data and is not to be construed as something to be literally reconstructed over time. It is likely, for example, that a larger area of forest will be desirable than was present originally. An incremental Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

45


restoration sequence should be developed for each generic management area illustrating the changes over time in perspective and section and accompanied by photographic documentation of current conditions. The product should be somewhat analagous to Repton's notebooks, but with more phases. The historic path layout is excellent and could, for the most part, be restored with no modifications, with the exception of adding a few small reinforced gathering spaces where tour groups gather and removing recently established trails. It has also been suggested that narrowing some of the trails would make them feel wilder in character and reduce some of the off-trail walking. With the smaller access trails in place, it should be possible to restore the rustic guide rails which once lined many of the trails. Their purpose, unlike the fence at the Point, is not to restrict access to whole areas, but rather to provide additional protection from trampling of slopes viewed from the pathways. As noted earlier, truly private areas with dense shrub growth in the Ramble simply invite trampling in contrast to a more open forest landscape. The original path design also included pebble gutters and stone reinforcing on the slopes along the stairways, which provided stormwater management and erosion control. This concept should be adhered to, although some of the materials may have to be modified. It is, for example, unlikely that maintenance will be adequate to sustain gravel as a major path surface. The restoration of the Gill will greatly enrich the plant and animal habitats in the Ramble. Because there has been minimal change to the site's hydrology, the original design should still be largely suitable. Work should proceed in phases, starting at the higher elevations and not initiated until path and architectural reconstruction has been completed in the area as well as restabilization of all bare soil areas. The incipient wetland, which has developed where the original stream has resurfaced, should be maintained and its channel formalized downslope. It affords a 'seep' habitat which is found nowhere else in the Ramble and may provide habitat on the adjacent slope for some plant species which may have been discouraged by the extensive filling elsewhere, which increased the distance to groundwater. Beech and white oak, for example, may be ideal on this slope. It is also critical to acknowledge the high level of controversy which centered on the

Ramble in the past. Continued coordination and review with interested groups and individuals is mandatory, as well as education of those in the political process. No comprehensive planning or management will be effected without the full participation of those who care for and care about the Ramble.

Initial Program Recommendations for The Ramble 1.

Initiate repair and replanting of bare and eroded areas with primary emphasis on steep slopes (concurrent control of bicycle use is mandatory)..

2.

Initiate control of knotweed, concentrating on areas where it is invading and not yet fully entrenched.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

46


3.

Prepare a base map of the Ramble, with topography, existing features, and a major canopy trees located.

4.

Prepare a site plant community type map.

5.

Map all disturbance, including all bare soil and exotics invasion patterns and develop generic management units and a five-year management program.

6.

Complete research and documentation of historic landscape and develop a long-term Schematic Design Plan.

7.

Prepare construction documents for the restoration of drainage infrastructure, architectural features, and path system, including adventure trails.

8.

Complete the stabilization of all bare soil areas, comprehensive knotweed control, and replant to achieve continuous canopy replacement before initiating major construction (includes closure of all outlaw trails).

9.

Initiate habitat enrichment and species diversification in those areas that will be unaffected by construction.

10. Initiate phased reconstruction, coordinated with concentrated replanting and management of disturbed margins. 11.

Restore and replant the Gill and formalize seep channeL

12.

Replanting of the margins of the Lake should be coordinated with the restoration of the Lake.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

47


The Hallett Nature Sanctuary In 1934, a small hill about four acres in size in the southeast corner of Central Park was fenced and established as a bird sanctuary. From then on, the site was experienced primarily as the view across the water of the Pond. White birches could be seen against banks of brightly colored azaleas and drifts of lawn descended down to the water. Access has been limited to an occasional tour and if it can be arranged, the trash is picked up beforehand. There is no path system, only trampled bare dirt trails crisscrossing the hill. Like the Ramble, the Hallett Nature Sanctuary is a completely artificial topography, created by adding fill to a bedrock outcrop. Two accidental 'springs' emerge from broken city water pipes near the top of the hillside. This site never supported native forest in the past; it is not a remnant of a natural landscape, but rather a neglected and overgrown planted landscape. Even today there are few large trees and no healthy native plant communities. Despite its mandate, the Hallett Nature Sanctuary does not shelter an abundant or diverse population of wildlife. The 1983 Wildlife Survey of Central Park conducted by John Hecklau showed limited use of the site by wildlife, although it is home to a large groundhog population, some squirrels, and mourning doves. There are a few migratory birds, such as warblers and nesting songbirds. It also provides a roosting site for visiting wading birds and raptors. The study speculated that the location of the site was too close to the city edge to be as attractive to wildlife as the more centrally located Ramble. The Nature Sanctuary is also a much more uniform site than the Ramble in terms of vegetative character. The site lacks the rich interplay of open and closed landscapes which typify the Ramble and is also simply smaller. Disturbance species abound, many naturalized from the original plantings, such as wisteria, privet, roses, mock orange, and honeysuckle. Much of the ground surface is trampled, which severely restricts the reproduction of desirable plants, although dense shrubs persist on the southern and eastern slopes. Because Hallett has so few visitors, it is largely unknown to the park public, except for those who crawl under the fence to set up camp inside. There were few strong feelings at all expressed about the area during the interviews, although most people assumed the site would continue as a fenced preserve. The New York City Audubon Society suggested, however, that public access to this area be reviewed, including evaluating the existing fencing. In character and purpose, the Hallett Nature Sanctuary closely resembles the Ramble except that it is fenced and use is limited and, like the Ramble, the site is in need of considerable renovation. Because there are so few strong feelings about the site, it might prove an ideal initial project for the Forest Management Team, if it is felt that practice is needed before tackling the Ramble. Reclamation techniques and approaches could be evaluated on the Hallett site before being used in the Ramble. Because the site is so small, it is ideal for work projects which could be coordinated with LIVE or even landscape management oriented ranger tours with a hands-on Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

48


component. The 'story' of urban ecology could be effectively told on this site and become a focus of the park's educational programs. If any access at all is permitted, even if only for management or an occasional tour, a

path system is necessary to eliminate trampling. The site will be only slightly less wild in appearance, but will be better protected from disturbance and compaction. Simple stepping stones, in character with a natural area, would be adequate and more effective than gravel on steep slopes. It is also imperative that access be effectively controlled if a sanctuary is to be achieved. This requires some improvements to the fence at the waterline, where it appears that people are frequently entering the site, as well as feral cats and occasionally feral dogs. The design concept should be developed and refined by the Restoration Task Force. The following guidelines are offered. The restoration of an open field condition is proposed for the top of the hill: a tall grass and wildflower meadow dotted with red cedar and fruiting shrubs, such as highbush blueberry, sumac, and arrowwood. Native forest communities should be fostered on the side slopes, predominantly oak and hickory with sassafras, black birch, and dogwood in the the understory. Rhododendron and mountain laurel in the shrub layer would provide evergreen cover. This may be one of the few places these plants can be established because they can be protected from picking by park patrons. Because the existing canopy is predominantly cherry flower and mulberry, it will be important to plant sapling size forest canopy species. The two broken water pipes should be repaired to eliminate both waste and erosion or treated as an opportunity to establish small-scale wetland habitats that might be especially useful for small reptiles and amphibians. The downslope channels of the two seeps could be formalized into naturalistic stream courses, one under forest conditions with blackgum, magnolia, and skunk cabbage and the other more open in character with sweet pepperbush, elderberry, and tussock sedge. These habitats should be established gradually, with plants incrementally removed and replaced. Because this site is fenced, it offers an opportunity to manage for herptiles that is unique in the park. Snakes, land turtles, and toads are easily captured and are, therefore, rare or non-existent in parks. We recommend that a wildlife shelter be constructed at a sunny open edge on the site. Such a shelter can be made using existing dead wood and branches on site. If well sited at a sunny open edge, which attracts herptiles, this could greatly increase winter survival rates. Planting to attract butterflies should also be considered. This overall design would also reestablish the historic character of vistas to the site from elsewhere in the park, using primarily native communities with rhododendron and laurel enhancing the earlier azaleas, and wildflower meadows replacing the earlier turf banks. At the same time, a fairly broad range of habitats should be represented, from uplands to wetlands in both woodland and field environments. Once protected from trampling and exotics invasion, these habitats could very reasonably be established and sustained here.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

49


In general, the maintenance of an adequate amount of dead wood on a site, both standing and fallen, is very important to wildlife. The Hallett site, however, has so much dead wood that vegetation reproduction is inhibited in places. Some selected removals will provide an opportunity to plant new native species. A prime focus for removals should be at the top of the hill where plugs of native grasses could be established in the gaps. Other planting sites will be created by the control of exotics.

Initial Program Recommendations for the Hallet Nature Sanctuary 1.

Develop a comprehensive plan for the site. Modify fence to provide greater security.

2.

Install a path system to provide access for restoration efforts and interpretive tours.

3.

Remove trash and debris.

4.

Repair broken water pipes. This will not preclude any future development of a wetland feature.

5.

Repair and replant bare and eroded areas.

6.

Initiate exotics control, with initial emphasis on Norway and sycamore maple, Japanese knotweed, and wisteria.

7.

Remove dead and dying trees on the plateau. Leave standing dead trees on side slopes and retain several large fallen logs on the hilltop. Rehabilitate soil and plant native grasses and wildflowers by plugs or sods. Continue exotics control. Once the meadow is dense and open, plant cedar and shrubs. Construct wildlife shelters. Add submerged logs along shoreline.

8.

Initiate removal of Norway maple in the canopy and replace with native canopy species. Continue exotics control. Gradually replace non-native invasives with native plant communities, including dense plantings along shoreline.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

50


A Habitat Corridor Network: Vegetation Management Elsewhere in Central Park to Foster Diversity in the Woodlands While this report has focused on the management of the three woodland areas, what occurs in the adjacent landscapes also impacts these sites. No landscape functions independently of its surroundings. In a remnant natural area, disturbance is typically severe at the edges and many sources of stress, such as the spread of exotics, . frequently enter from the edges. Large entrenched areas of knotweed, for example, immediately adjacent to the woodlands will spread and require monitoring and maintenance. More subtle, but just as important, are positive impacts stemming from adjacent landscapes. It has long been documented that diversity diminishes in landsape fragments which are isolated from larger areas of natural habitat. Very positive benefits to each of the woodlands and the wildlife they support could be provided by establishing a network of habitat corridors connecting the woodlands to each other as well as to other more natural areas in the park, such as ponds, wetlands, and wildflower meadows. The idea of such a network in Central Park might initially seem rather ambitious; however, the perimeter landscape offers many opportunities to establish significant corridor links without significant changes in the use or design of the park. The park's perimeter is generally treated as a layered woodland margin and buffer to the park, and is currently being renovated a section at a time. While each area has an historic character which should be respected and may entail complicated issues of use and access, both future planting and management plans should foster the use of the perimeter as a habitat corridor. Although no major alterations should be undertaken without appropriate review, the following guidelines are proposed for consideration.

1.

Provide a continuous corridor of layered forest vegetation with canopy, understory, shrub, and ground layer plants connecting the three woodland areas of the park.

2.

The corridors should be no less than IOO-feet wide wherever possible.

3.

A corridor margin of early successional vegetation is recommended, including both sh!ub and herbaceous landscapes.

4.

Wherever forest vegetation is not feasible, meadows of native tall grasses and wildflowers, mown annually, with occasional native shrub clumps are preferable to turf as the connecting piece.

5.

Multi-layered plantings of horticultural species are also preferable to turf, as long as none of the species is a naturalizing exotic which might run rampant in the less intensively managed woodlands. As replanting is required in these areas, native forest species should gradually be favored over exotics.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

51


6.

Species requiring routine pesticide management should be removed from the wildlife corridors and replaced with native species.

7.

Exotic invasives should be vigorously controlled in the wildlife areas and be given higher priority than elsewhere in the park, except in the woodlands themselves.

8.

A 100-foot margin around each of the woodland areas should also be managed as part of the habitat corridor system. Exotics control is especially critical here. Similarly, native plant community types found at earlier stages of succession, from shrublands to native meadows, are desirable. Mowing tall grass and wildflower margins will provide some measure of exotics control which can be augmented by mechanical means.

9.

It is preferable that a pond have a soft vegetated edge wherever its margin

meets the corridor network. Where this is not presently the-case and only a paved edge is available, large tubs of native aquatic vegetation should be placed in the pond itself. These tubs can be set on boulders to achieve the appropriate water depth. Appropriate species include sweet-scented water lily (Nymphaea odorata), bullhead lily (Nuphar variegatum), arrowhead (Sagittaria latifolia), pickerel weed (Pontederia cordata), and blue-flag iris (Iris versicolor), among others. ..In addition, dense thickets of native wetland shrub species, such as sweet pepperbush (Clethra alnifolia), buttonbush (Cephalanthus occidentalis), highbush blueberry (Vaccinium corymbosum), winterberry (Ilex verticillata), and waxmyrtle (Myrica pensylvanica), can also be planted in larger boxes set in the pond where they will be protected from human disturbance. As these species also tolerate drier conditions, additional plantings in the adjacent uplands will enhance the vegetated corridor and should be augmented with groves and thickets of lowland trees, such as tupelo (Nyssa sylvatica), walnut (Juglans nigra), butternut (Juglans cinerea), sweetbay magnolia (Magnolia virginiana), and speckled alder (Alnus rugosa). 10.

Additional wetland habitat can, in places, be created by storing stormwater runoff in depressions and swales in the habitat corridors. For example, where a low-lying turf area is being converted to meadow to complete a missing link in the corridor network, it may be desirable to regrade the area to trap and retain runoff to create an intermittent wetland, either herbaceous or woody.

11.

Stands of evergreen vegetation could be established at reasonable intervals along the corridor's length averaging no more than 300-500 feet apart. Species suitable beneath a forested canopy include hemlock (Tsuga canadensis), American holly (flex opaca), and inkberry (Ilex glabra). White pine (Pinus strobus) requires more open landscapes to become established and can be used in meadow areas.

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

52


12.

Native vines are especially desirable in the habitat corridors, especially Virginia creeper (Parthenocissus quinquefolia) and grape (Vitis spp.).

13.

The landscape character of the habitat corridor network should be integrated into the overall design character of the park and should not conflict with other scenic and aesthetic goals. These are managed landscapes, not simply areas where nature is left to run wild, and a naturalistic character compatible with its .' surroundings is desirable.

Soil Rehabilitation & Establishment of a Soil-Making Operation at the Mount The idea to expand the composting operation at the Mount has been around a long time. The demand for composted leaves in the park for renovation efforts always exceeds the supply and will surely grow once woodland restoration begins. The existing site presently is still disorganized, despite recent improvements and could accommodate a far larger and more diverse operation with no increase in area, especially if a vertical composting operation replaces the existing horizontal set-up. A solid base and drainage control are also important and will require resurfacing of the roadways and work areas. The site is also used for temporary storage of materials, such as excavated boulders, a compatible use that could continue in the future. Current concern largely centers on the perception that the Mount is slowly, inexorably expanding and that without adequate fencing may attract illegal dumping. Additional screening is also necessary. Ideally, the operational area should -be confined to within the boundaries of the old walls and structures, some of which could be restored to provide screening which is historic in character, while protecting potentially valuable archaeological resources from disturbance. The relic and rebuilt walls could be augmented with earthen banks and additional planting to create views of the Mount site that are more evocative of the character of the park than the more conventional rows of columnar evergreens often used to screen such facilities. The problems of urban soil are legion and range from contamination by toxic materials, like deicing salts and airborne pollutants, to a lack of organic matter. These factors are compounded by the extensive area of made land in Central Park, where natural topography was recontoured, wetlands drained, and large amounts of fill were brought in to create a rolling, upland topography, often with fairly steep slopes. The depth of fill also greatly increased the distance to groundwater creating conditions less suitable in places for beech and oaks and other desirable mast (nut-producing) species. These made soils lack the stability of natural soil stratigraphy and have been even more vulnerable to the stresses of trampling and erosion than the native soils which have also suffered greatly under the impacts of visitor use. There are several valuable materials which could be stored at the Mount and incorporated as soil amendments and stabilizers along with compost. In many areas of the woodlands the importation of large quantities of topsoil may be far more costly than adding and mixing soil amendments, such as manure, humus, leaf mold, compost, dredge spoil, sand, and expanded slate, with the existing compacted

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

53


subsoils. Similarly, excavated subsoil from elsewhere in the park could be cleaned and mixed with various amendments to make 'topsoil' useful to various restorations. The leaf compost operation should be expanded as much as possible. Some additional equipment may be necessary. The Parks & Recreation Department already has one vacuum truck and has identified a need for a Royer shredder. There is, at least for many years, an almost limitless need for organic matter. A more structured facility would permit more efficient rotation of compost. Humus in the form of peat should also be stockpiled at the Mount and used wherever a more slowly decomposing form of organic amendment is desired. In the woodland areas, such a slow release of nutrients is always preferable to the sudden boost from synthetic fertilizers. Additional research should also be done to evaluate the use of physiological bacteria, such as innoculating soils with symbionts. One of the potentially most useful products to combat soil compaction in heavily trafficked areas and where soils have an extremely low pore space is expanded slate. Expanded slate is a commercially avaliable material which is produced by heat-expansion to give it a 50% pore space. It is inert, porous, and rigid and may be mixed with soil in proportions ranging up to 33%. Soil amendment studies were conducted at Hain's Point of the National Capital Parks Unit of the National Park Service in a heavily used picnic/playground area with no restrictions on trampling. After four years, the percentage of pore space remained nearly 50% on sites after the incorporation of 33% expanded slate by bulk to the soil surface soil, where previous pore space levels were under 42%. The addition of sludge in the experimental plots appeared to have little effect on compaction. Coarse sand and sintered fly-ash (a heattreated fly ash used as a soil amendment) were less effective than the slate. Ideally, trampling will be controlled in the woodlands; however, some indiscriminant trampling is inevitable and the addition of products, such as expanded slate, may be invaluable where soil structure is poor or the likelihood of pedestrian use is somewhat higher. The existing fill soils have high levels of ultra-fine sands and coarse fragments and are often both poorly drained and droughty. Expanded slate may provide increased moisture retention while improving drainage. Powdered rock dust is also worth considering as an alternative to synthetic mineral fertilizers. The depth of fill often prevents the soil from gaining nutrients from the action of weathering of bedrock. It should be evaluated in the woodlands as a mineral amendment which can be sprinkled on top of the soil or worked into the soil when stabilization is undertaken. Large boulders are extremely valuable and should never be simply disposed of. They can be used as aesthetically pleasing rip-rap and to create artifical'bedrock' surfaces as part of indian-file trails and stream channels, and to provide access to special features, such as the water's edge. Cinders and deicing salts are not suitable for storage at the Mount. The risk of contaminating the soil amendment products is just too great. Similarly, no other potential contaminants should be considered for storage. Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

54


Bibliography

Barlow, Elizabeth, with Vernon Gray, Roger Pasquier, and Lewis Sharp, The Central Park Book (New York: The Central Park Task Force, 1977). Bruns, Diedrich and Luz, Frieder, "Improvement of Wildlife Habitat Networks in Agricultural Landscapes: Examples from West Germany. Paper presented at IFLA (International Federation of Landscape Architects) Conference, Boston, 1988. Central Park Conservancy, Rebuilding Central Park: A Management and Restoration Plan, (New York, 1985). Central Park Conservancy, "Soil Survey and Management Report" (1981). Central Park Conservancy, "The Bird Sanctuary" (unpublished report). City of New York, Department of Parks & Recreation, "Pelham Bay Park Management Study" (1987). City of New York, Department of Parks & Recreation, Natural Resources Group (Draft in Progress, 1987), "Natural Areas Maintenanc~ Guide". Cramer, Marianne; Heintz, Judith; and Kelly, Bruce", Vegetation in Central Park, Final Draft", (New York: Central Park Conservancy, 1984). Craul, Phillip J., editor, "Urban Forest Soils: A Reference Notebook", prepared for an Adult Education Workshop, University of Maryland, April 26-28, 1982. Craul, Phillip J., "Assess Urban Soil for Better Tree Survival", American Nurseryman, October 1986, pp. 71-78. Deloitte, Haskins & Sells, "Central Park Management Study", (1988). Demcker, Robert, "Central Park Plant List and Map Index of 1873, Updated in 1966 by Arturo Parrilla, Department of Parks, Under the Supervision of Henry Hope Reed, Curator of Central Park", (New York: The Frederick Law Olmsted Association and the Central Park Community Fund, 1979). Elliott, Sarah McCarn; Farrell, Kathleen B; Girards, Christina; Pohner, Lambert; Post, Peter W., and Rosenberg, Sheila G., "Report on Birding Areas in the Ramble of Central Park: Descriptions & Recommendations", (The C~ntral Park Birdwatchers, New York, 1979). Harty, Francis M., "Exotics & Their Ecological Ramifications", Natural Areas TournaI, vol. 6, no. 4, pp. 20-26. Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

55


Hecklau, John, "Central Park Wildlife Inventory", (1983). Kelly, Bruce; Fitch, James Marston; and Winslow, Philip N., "The Ramble in Central Park: An Historic Landscape Master Plan, prepared for the New York City Department of Parks & Recreation". McDonnell, Mark J., "A Forest For New York: ;The Challenge of Preserving Urban Natural Areas", The Public Garden, April 1988, p. 28-31. Patterson, James c., "Soil Compaction & Its Effects Upon Urban Vegetation", Ecological Services Laboratory, National Capital Parks, National Park Service, Washington, D.C. Weber, Jill; Olson, Gerald W.; and Lopez, Stephen H., "Tour of Soils of Central Park in New York City", Cornell Cooperative Extension Bulletin, Miscellaneous Bulletin 132 (1984).

Phase One: Landscape Management & Restoration Program for the Woodlands of Central Park

56

Landscape Management and Restoration Program for the Woodlands of Central Park  

Phase One Report: Consensus of the Interv~e~s, Key Issues & Initial Program RecommendatioJ\s

Landscape Management and Restoration Program for the Woodlands of Central Park  

Phase One Report: Consensus of the Interv~e~s, Key Issues & Initial Program RecommendatioJ\s