Forum Journal & Forum Focus

The Treatment of Historic Landscapes 

05-30-2019 10:14

Landscape treatment is an intervention carried out to achieve preservation goals. It is the fourth step in the preservation planning process. The preceding steps determine what treatment is appropriate for each historic landscape or its specific features. These steps include: thorough research of the historic record, conducting an inventory of the existing conditions, and completing an analysis of the character-defining features of the landscape over time. Establishing historic context, which is currently lacking for many types of historic sites, may also be a component of the planning process.

One component of the preservation planning process is determining the period of significance for the landscape. The period of significance may vary from a specific date, as in the case of some battlefields, to a series of years, as in the case of a residency associated with a historically important figure, or an extended period, as in the case of a town commons or public ground that has been altered over the course of two centuries through an aggregation of culturally valuable elements.

The criteria for significance in historic landscapes in American culture are the same as those applied to other cultural resources in the National Register process.1 In cases in which a historic landscape and historic structures constitute a property, the reasons for significance and the period of significance for these different resources mayor may not coincide. An understanding of the landscape as a continuum through history is important in focusing on the cultural value of the landscape as a separate issue from the value of other historic resources. The level to which the historic landscape retains the character and features of its historic period or periods-its integrity-is also a consideration in determining a treatment. Significance and integrity issues influence treatment decisions as well as the historic research, existing conditions, and analysis findings.

Additionally, the selected treatment needs to match such planning objectives for various aspects of the ongoing life of the landscape as visitor services, educational programming, financial resources, maintenance capabilities, intended interpretation, and other factors. Various owners or stewards of a historic landscape may have widely varied objectives and limitations governing preservation-treatment choices. Selection of a treatment is a sequential process that leads to a decision. The complexity of reaching that decision is governed by the nature of the historic landscape. the preservation-planning outcomes, and the objectives and limitations of the landscape owner/steward.

The knowledge of the landscape resources gained through each planning step forms a basis for treatment decisions. Using the framework set forth in the Secretary of the Interior's Standards for the Treatment of Historic Properties and the Guidelines for the Treatment of Historic Landscapes, 2 treatment of the landscape follows a gradient of intervention. The four treatment terms and their definitions:

  • Preservation is undertaken to retain and maintain historic features or materials, including repair and replacement in-kind and removal of such negative, contemporary elements as invasive plant materials; includes protection or stabilization to secure the historic resources, preventing further damage and slowing deterioration.
  • Restoration is undertaken to represent the historic landscape of a targeted period rather than the property as evolved. Repair and other modest treatments may be used in combination with the addition of lost historic features or the removal of later additions to recapture the targeted period. This treatment must be based on a high level of documentation so that conjecture about the period landscape can be avoided.
  • Reconstruction is new construction undertaken to replicate the exact form, features, and details of a landscape or individual elements of a landscape on the original site. Again, documentation must be sufficient to replicate the landscape without speculation about the original form. A compelling reason for re-creating the historic appearance of a landscape using new construction is to enhance the visitor experience.
  • Rehabilitation is undertaken to retain the historic character and features of the landscape while adjusting to suit contemporary use in a manner that is compatible with and distinguishable from culturally valuable resources.

Treatments range from modest to ambitious in scope, and inexpensive to costly in execution. Preservation is a conceptually conservative approach; rehabilitation, which addresses contemporary-use issues, may range from conservative to radical in approach. Both restoration and reconstruction seek to recapture partially or wholly lost elements of the historic landscape from detailed historic records and are intensive in nature. The ease of describing historic landscape treatment under these four headings is in direct contrast to the frequent difficulty in determining and implementing such treatment. Existing conditions and preservation objectives, for example, often demand that more than one treatment be applied to different elements of the same landscape. Projects in various parts of the United States are explored in the following discussions to reveal the complex nature of historic-landscape resources and the challenges of their preservation treatments.



The Confederacy staged its final campaign north of the Mason-Dixon line from July 1 to 3, 1863, at Gettysburg, Pennsylvania.4 President Abraham Lincoln delivered the Gettysburg Address there during ceremonies dedicating the national cemetery. The first example of preservation and memorialization of a Civil War battlefield began just three weeks after the battle and continued primarily through the late nineteenth century, although monuments are still being added today. Gettysburg has military, political, and preservation significance for these reasons.

Planning Process & Treatment Approach

Using the wealth of late-nineteenth- and early-twentieth-century documentation, a boundary study was undertaken to resolve questions about lands within and adjacent to the Gettysburg National Military Park.5 The study resulted in several recommendations: to add fourteen parcels that contained outstanding resources, encompassing 1,900 acres of currently unprotected land; to delete several small parcels; to cooperate with the Commonwealth of Pennsylvania, local governments, and the private sector to protect the historic battlefield settings; to work with landowners toward protection of outlying monuments; and to encourage creative approaches to land protection in order to maintain compatible private land uses within the park.

Following this study, a planning process was initiated addressing current and valuable adjacent parkland that had been divided into sixty-nine viewshed parcels. Each parcel was ranked for its impact on the battle action and outcomes and its interpretive value to the visiting public. These rankings were combined to develop a composite that revealed areas of the highest, median, and lowest value to the history and interpretation of the battlefield. Efforts were then focused on the areas of highest value to address the potential reconstruction of lost elements of the battle scene.

Both of these efforts, as well as other work, addressed the historic significance, management objectives, current condition, and major issues of this 5,600-acre park located in south-central Pennsylvania, and contributed to an updated 1991 Statement of Management for the Gettysburg National Military Park, which recognizes the dual nature of the park as a battle-field where military engagements took place and their archaeological remnants remain, and a memorial landscape where extensive monumentation was developed by veterans and subsequent sponsors. The objectives for the landscapes of the battlefield are stated as being:

"To manage the park as a memorial landscape that not only reflects the prebattle 1863 rural agricultural environment but includes those superimposed post-battle elements (monumentation, avenues, interpretive devices, facilities, etc.) that are necessary for commemoration and visitor understanding of the battle. No restoration of structures or landscape elements may create an anachronism-that is, all elements must have co-existed during a single historic period. Essential landscape features may include: structures, fence lines, field size, wetlands, wet areas, waterways and springs, boulders, orchards, woodlands, woodlots, roads and traces, ditches, vegetation characteristics (height/texture/ location.)" 6

In the past, elements of the battlefield had undergone treatments to return them to their appearance in 1863, with later accretions removed, while memorial elements within the same area might be retained. Thus an anachronistic setting was created. The policy of no anachronisms-having all elements of a particular area of the landscape reviewed for coexistence in history-is an important one in approaching this complex battlefield and memorial landscape.

Treatment Implementation

Two projects to reconstruct historic period fences and orchards were undertaken in selected high-priority areas currently in use as cropland or pastures for grazing. Because the actions required reconstruction of lost features rather than repair or replacement in-kind, a Section 106 review of the actions was required. Section 106 is a process of submitting actions that will impact recognized historic resources to the President's Advisory Council on Historic Preservation for review. The proposal to reconstruct ten orchards and several important fence lines was documented with details of period mapping and period photographs. It was approved and, in the summer and fall of 1991, installation of the orchards and fences was undertaken.

The orchards were important for their spatial organization and land use, rather than any implication that they replicated the original fruit species, which is unknown. Interestingly, the proposed fruit trees are blight-resistant, native crabapple varieties. These trees have the same general size and shape as other apple species, they are hardier than many fruit species, and they will not require intensive chemical management. They will present the historic appearance without requiring crop-yield management, intensive mowing, or constant pruning; a significant staff burden is not added with this reconstruction.

Historic fences delineated the landscape by zones, enabled the rolling topography to be understood, and defined several important battle encounters. The wooden five-rail fence along Pickett's Charge was one of those proposed for reconstruction. This fence line reveals to the park visitor the conditions that match veterans' accounts of the charge during which troops ran across a field along the fence line to a low, muddy area and up a small slope to engage in combat. Without this line of fence the organization of the area would be difficult to understand. In both the orchard and fence reconstruction, disturbance of the soil was limited to rootball and fence-post areas so that any archaeological evidence would be preserved in situ to the greatest possible extent.


Other aspects of this case study include the addition of important adjacent lands, the management of crop production areas in ways that are compatible with the historic scene, management of forest and woodlot for historic appearance, and ongoing monument care. A long-term effort to more completely evoke the battlefield to the park visitor has begun with the reconstruction of lost orchards and fences. These efforts and others will continue for several years.

In assessing this project against the Guidelines, the research was fully adequate to form a basis for the work. "Choosing a reconstruction period that is consistent with the period represented by remaining associated buildings (and structures) on the property," is a recommended treatment under reconstruction applicable to the objective of not creating anachronistic settings. Guidance for spatial organization includes "replacing entire vegetation features that contributed to the historic spatial relationships." This recommendation was carried out at Gettysburg in the reconstruction of the lost orchards. While reconstruction is undertaken infrequently, the fences and orchards of the historic period that persisted through the memorial period were lost character-defining elements of the landscape. Conjecture about the original landscape was avoided and interpretation was greatly enhanced. The views, spatial organization, and topography of the areas treated are more evident and understandable with the fence and orchard features in place.



Monticello was the hilltop estate and farm of Thomas Jefferson7 Recognized as an architect and landscape architect by interest and experience, Jefferson developed Monticello through years of planning, testing, construction, and cultivation. The most significant period in this process was the postpresidential period from 1809 until Jefferson's death in 1826. This period of significance-when Jefferson implemented his vision for Monticello as a ferme ornée, or ornamental farm-is the primary focus of the Thomas Jefferson Memorial Foundation's efforts. Monticello is listed as a World Heritage Site for its association with Jefferson and is of international importance.

Planning Process Treatment Approach

The Thomas Jefferson Memorial Foundation has for nearly two decades benefitted from the efforts of an enlarged staff of landscape preservation professionals. The disciplines of curation, restoration, historic horticulture, and archaeology have contributed since the early 1970s to the recapture of the Jefferson legacy at Monticello.

From 1826 to the late twentieth century much of the character and features of the Jeffersonian period were lost or altered. The topography, circulation systems, vegetation, spatial organization, and objects of 160 years ago had been lost or altered by natural and human forces. Jefferson's writing and drawings, however, are voluminous and detailed. These written and graphic resources have been studied in detail for guidance in determining the appearance and details of the ornamental and utilitarian areas of the landscape during the period of significance. In each project initiative Jefferson's design intent and evidence of the historic condition are gathered from documentary sources. At times these sources present conflicting information, especially in the realm of what was planned versus what was actually constructed. Because this era is a prephotography period the reliance on period photographs, which is often critical to discerning the as-built condition in historic landscape projects, is not available for Monticello's primary historic period.

Archaeological investigations have been undertaken to verify or fine-tune the research findings. The findings of each investigation have been integrated with historic research to develop a treatment approach. Each project moves toward implementation only when it can go forward with a high degree of accuracy. The following quote by Bill Kelso of the Thomas Jefferson Memorial Foundation provides a perspective on the archaeological research findings:

"I will be the first to admit that to the list of known elements of Jefferson's garden–-i.e., its fences, planting beds, walls, terraces and orchards—archaeology adds very little. On the other hand, what we learned about the precise location, materials, and construction details of these garden elements and which elements planned by Jefferson were actually built has proven essential to any plans for reconstruction.”8

From 1979 to 1985 a series of features were investigated using landscape archaeology. The roadside tree stains located the First Roundabout when paired with Jefferson's survey records. The ha-ha ditch surrounding the West Lawn was located through intermittent trenching. The location and extent of the garden and orchard fence and its critical axis off the house was determined by uncovering fence-post holes. The configuration of the vegetable terraces and related stone retaining wall and Garden Pavilion were clarified through garden-wall excavations. Dark-stained root cavities from orchard trees, grapevines, and berry squares were unearthed.

Monticello's historic horticulture begins with Jefferson's garden book. Jefferson's interests in botanical science and practical horticulture included embellishment of his estate, a curiosity about native and rare plants, and a desire to find and use plants that would help our nation prosper. The plants grown at Monticello came from American survey expeditions, French and Italian viticulture, and more, creating an experimental landscape with success and failure duly noted. His records are personal and list many plants by their common names. Detailed research from Jefferson documents was paired with such period plant sources as Philadelphian Bernard McMahon's The American Gardener's Calendar (1806) to decipher Jefferson's names. These names are traced through time to present nomenclature as possible. Today Jefferson's plants as seed, scion, or rooted stock are searched for locally, nationally, and worldwide.

Findings from the investigation of Jefferson's records, historic horticulture research, and archaeological investigations are brought together in a carefully recorded decision-making process to arrive at the intended landscape-treatment project.

Treatment Implementation

The Monticello landscape has been in the process of recapture for the past sixteen years. The work of the multidisciplinary professionals on the property has targeted various components of Jefferson's gardens, park, and ornamental farm beginning with the East and West lawns and proceeding to the elements within the First Roundabout drive and proceeding sequentially down the topography to the successive vegetation and circulation elements.

The individual elements and features within these areas have been the subject of reconstruction treatment projects. The vegetable terraces, framed by an earthen slope above and a rubble stone wall below, extend for 1,000 feet to the south of the house. This plateau was reshaped from the slumped soils and wall. The vegetable beds follow a detailed plan by Jefferson that organized the crops and laid out the garden in uniform beds. The shapes of the beds that had been lost because of deep plowing and erosion were recaptured by measuring from the unearthed gate posts. The stone wall, which varied in height from less than two feet to more than ten feet, was rebuilt primarily with the original stone in the same location. Intact portions of the base stones laid on grade were retained. Some of the stones had been relocated and these were reclaimed. Intact portions of the wall were used as models to be matched in the reconstruction. The sub-mural beds were reconstructed and planted with Jefferson's tender varieties of fruits and vegetables. The Garden Pavilion was reconstructed according to Jefferson's specifications in the longer terrace retaining wall.

The orchard, vineyard, and berry squares in the meadow south of the vegetable terraces have been replanted according to Jefferson's pattern, verified in part by root-cavity stains. Fruit trees, vines, shrubs, and cane of Jefferson's collection have been replanted when available. Some trees have been brought from other countries and have been quarantined temporarily by the USDA until they can be added to the orchard. While certain original fruits have been found, others are no longer in cultivation. Period plants that are available offer a substitute and efforts to find missing links continue.

Treatments other than complete reconstruction are employed at Monticello. As an option to complete reconstruction, small portions of the paling fence and ha-ha ditch are reconstructed in discrete areas as samples of these enclosing elements. They are interpreted to visitors with signs and brochures. The row of slave dwellings and workshops along Mulberry Row are interpreted through the use of a remnant chimney, signs, and an illustrated brochure. A small rehabilitation treatment is included near the gift shop where a sand-clay path has been constructed to accommodate visitor movement patterns in an area where none existed in the historic period.


Consistent work on this site beginning in the early 1970s makes Monticello a unique situation. The level of detail in Jefferson's writings provides ample basis for the development of hypotheses about the form and content of the landscape during Jefferson's residency. The team works from these writings in other ways to verify, disprove, or fine-tune documentary evidence. Each implemented project is developed with the benefit of hundreds of professional hours and intense scrutiny, attaining a high degree of certainty and limiting conjecture. This work is the ideal form for a reconstruction process that requires detailed documentation and the limitation of speculation. Additions within the landscape, where the actual plantings include period plants rather than those directly accredited to Jefferson and Monticello, are portrayed with honesty in property visitor brochures.

The spatial organization, circulation system, vegetation, structures, and objects of the Jeffersonian postpresidential period have been significantly recaptured in the areas of the property nearest the house. More remains to be done both on the property and within its expansive viewshed. but work to date is a model for other sites, setting a standard for the rigor required when a large-scale reconstruction is undertaken.



The Benjamin Franklin Parkway9 was initially envisioned as a broad, urban boulevard connecting the proposed art museum and city hall. The Trumbauer, Zantinger, and Cret plan for the Fairmount Park Art Association developed in 1907 showed the intent of the parkway "to furnish a direct, dignified, and interesting approach from the heart of the business and administrative quarter of the city, through the region of educational activities grouped around Logan Square, to the artistic center to be developed around the Fairmount Plaza, at the entrance to Philadelphia's largest and most beautiful park."10 By 1917 the Fairmount Park Commissioners adopted a highly articulated plan by Jacques Greber that configured the parkway as it was constructed The segment from the art museum to the reconfigured Logan Square included a central, broad avenue flanked by twin pairs of trees; a secondary drive on each side was lined with five tree rows. From Logan Circle to city hall the parkway was limited to a single row of trees on each side of a broad avenue, culminating in a small circular green space at the corner of city hall. Development of the parkway began in 1917 and was completed in 1923.

Planning Process & Treatment Approach

The decline of the parkway's trees was noted in the late 1970s. In the spring of 1987 an inspection of the 219 red oak trees on the center aisles revealed that eighty-nine had been removed and that 108 required immediate removal due to disease, dieback, and the resulting unsafe conditions, leaving only twenty-two trees in fair to good health. Although the remaining trees had good trunk size, canopy sizes were smaller than expected. Age, soil compaction, air. pollution, drought, deicing salts, temporary wiring, staples and nails from posted notices, and other environmental factors had all contributed to the decline of tree health and scale disease further weakened the distressed trees. The sycamore trees on the side aisles were also in distress, suffering from anthracnose, a disfiguring disease, and canker stain, a fatal disease. These are also in poor health. Formerly five rows deep, they now form fewer than three rows, which reflect many losses and gaps.

The problems of the parkway included historic, visual, aesthetic, ecological, horticultural, and use components that required a comprehensive approach to solutions rather than a simple replacement of dead and dying trees. A systems approach was taken to address these complex problems by considering all relevant factors including sunlight, microclimate, circulation, normal and peak uses, utility systems, maintenance operations, and budget. All the research and existing conditions substantiated the decision to remove the remaining red oak trees and replace the entire tree population of the center aisles. This rehabilitation of plantings was a reinterpretation of the Beaux-Arts formality of the parkway incorporating contemporary concepts and techniques about urban ecosystems. The intent was to replace the trees with urban-tolerant species planted in a manner that would sustain their health and contribute to their longevity.

This wholesale removal and replacement of the trees was a highly emotional issue for the community. Informational meetings were held to inform the public. Project signage was installed to educate parkway users and a brochure was developed by the Fairmount Park Commission to spread the word further and to request private donations to aid this first phase of the project. The sycamore trees are scheduled to be replaced in a second phase, after the first set of plantings begins to achieve some stature.

Treatment Implementation

All of the red oak trees and stumps were removed in early 1989. These removals revealed gnarled, stunted root systems- the result of compacted soil conditions. Each curbed tree aisle included two fourteen-foot planting areas that included trees and turf and a ten-foot central walk. The former red oak trees had been planted four feet from each curb and spaced on thirty-foot intervals. This spacing was retained while the placement was shifted to seven feet off the curb, centered in each planting area, so that wounding to the tree base from vehicles would be less frequent.

The details of the rehabilitation approach included the choice of three species- red oak, red maple, and sweet gum trees-to replace the monoculture of red oak trees. The choice of these mixed plantings resulted from the need to diversify in order to avoid blights and diseases that had in the past destroyed entire formal, urban tree features. The trees chosen had comparable upright forms and medium foliage and branch texture, so that while diversity was built in, similar visual quality was also provided to reinforce the intended formality.

After choosing the species, the design of the environment for the trees was approached. Urban tree research has indicated that trees planted in pits are less likely to develop healthy root systems than those planted in larger areas of prepared soil. Continuous trenches six feet in width were excavated three and a half feet deep; 280,000 cubic feet of old soil and rubble was excavated in this operation and replaced with a gravel drainage layer and 11,000 tons of special soil mix. The soil medium was a sandy loam and included six parts topsoil, one and one half parts sand, one part mushroom soil, and two parts large stones. This soil was placed over a ten-inch, filter fabric-wrapped gravel layer to provide a drainage zone beneath this compaction-resistent [sic] soil mix. The use of continuous trenches also allowed for the installation of utility and communication lines in underground conduits.

Philadelphians are seeing the replanted portions of the parkway today as they appeared in the 1920s. The 219 trees had experienced three growing seasons by 1992. These trees have now settled in and are beginning to grow. Within seven or eight years they will have some stature and will visually become replacements of the lost and removed trees. A maintenance program has been developed to address the cyclic needs of these new trees. Mulching to keep moisture in the ground and to prevent mower damage to bark, pruning to stimulate and direct growth, watering when transpiration exceeds water replacement, integrated pest management, and turf care are proceeding regularly. These maintenance activities, which cost $100,000 annually, are funded in two components-$40,000 in mowing and trash removal from the city and $60,000 in private funds to support the other needed activities. Public education is also continuing to encourage respect for the trees and the parkway environment.


This project rehabilitates the center portion of the historic parkway. The Guidelines indicate that rehabilitation seeks to maintain the historic character of the property but allows for alterations that are necessary for contemporary use. For this project the trees were not replaced in kind in exact locations; ecological and horticultural considerations directed a more diverse planting and a slight shift in location to further protect the tree trunks. Mulching around the trees is also an adaptation for tree health that changes the visual character from turf growing up to tree trunks. These three case studies present preservation treatment issues, resolution, and implementation for diverse historic landscapes. The determination of an appropriate treatment approach must be based in a thorough planning process to effectively address the integrity and significance of the historic landscape. While the treatment applied in this project appears to fit the rehabilitation guidelines, the particular aspects of replacing a formal feature of this type, with some adaptations, are not completely addressed in the text.



1 Refer to National Register Bulletins 16A and 16B for discussions of the criteria for significance and making a case for the significance of a particular resource. See also National Register Bulletins 18 and 30 for specific discussions of the significance and integrity issues for cultural landscapes, both designed and vernacular.

2 See the draft Guidelines for the Treatment of Historic Landscapes, May 1992, for an expanded discussion of these treatment terms and their application to historic landscapes. Overall treatment terminology is addressed in The Secretary of the Interior’s Standards for the Treatment of Historic Properties, October 1992.

3 An individual grant from the National Endowment for the Arts, Design Arts Program for 1991-92. made this work possible. Information on sixteen projects was gathered.

4 The primary contacts for the Gettysburg Military Park case study were Reed L. Engle, landscape architect and site manager, and Kathleen G. Harrison, historian, the interpretative staff at Gettysburg. The work described was developed by many people within the National Park Service, primarily at Gettysburg and at the Mid-Atlantic Regional Office in Philadelphia.

5 USDOI/NPS Mid-Atlantic Regional Office and Gettysburg National Military Park, Boundary Study, Gettysburg National Military Park, August 1988.

6 National Park Service, Gettysburg National Military Park, Statement for Management, Outline of Planning Requirements, May 1991, Gettysburg, Pennsylvania, page 17.

7 The Thomas Jefferson Memorial Foundation has for nearly two decades benefitted from the efforts of a growing staff of landscape preservation professionals. The areas of curation and restoration were added first with William Beiswanger hired in 1971 for furniture drawing, moving to research assistant position in 1975. In 1977 Beiswanger developed a report on Jefferson's Grove and Rudy Favretti was retained as a landscape consultant. Professional horticulture was add in 1977 with the naming of Peter Hatch to the position of superintendent of grounds and he begins researching Jefferson's historic plant material. In 1978 the report on the vegetable terrace, orchard, vineyard, berry patches, and nursery was presented to the board oftrustees.1t included a recommendation that an archaeologist be hired. William Kelso was appointed as archaeologist in 1979 and he began excavation of the vegetable terrace. Since 1979 these professionals in restoration, historic horticulture, and archaeology and their staffs have worked together on a series of projects directed toward the clarification and detailing of the Jefferson legacy at Monticello.

 8 Kelso, William, M., notes from Summary Report of the Archaeological Investigation of tile Garden at Monticello, 1979-1980. Thomas Jefferson Memorial Foundation.

9 The primary contact for the Benjamin Franklin Parkway case study was Michael P. Nam, ASLA. South Street Design Company, project consultants. The client for the work is the Fairmont Park Commission of the City of Philadelphia, working with private contributors through the John Bartram Association under the Logan Circle/Parkway Trust.

10 Fairmont Park Art publication.


Publication date: May/June 1993


Author(s):Patricia M. O'Donnell