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The Inventory and Analysis of Historic Landscapes: Defining the Approach 

12-09-2015 17:35

Increasingly, preservation projects include a historic landscape component that requires a basic understanding of the principles and practice of historic landscape inventory and analysis. Federal and state agencies, local governments, architects, engineers, and landscape architects as well as almost every breed of preservationist are confronting historic landscape-inventory issues that have little in the way of established precedents to guide them. Additionally, years of neglect, overuse, and mistreatment have created an urgent and immediate need for information pertaining to the historic landscape. Inventory and analysis, which constitute the basic mission of each state historic preservation office and the bread and butter of free-lance preservation consultants, are the much misunderstood new tasks associated with most historic landscape projects.

Why inventory historic landscapes? Because most historic landscapes have not been inventoried, they often are officially invisible and overlooked in the planning and review processes. Until considerably more historic landscapes are listed in the National Register of Historic Places and increased numbers of historic landscape features are evaluated as contributing resources within historic districts, historic landscapes will remain among our nation`s most threatened and venerable historic resources. Most existing registered properties include some landscape resources, yet the majority of the existing nominations do not address them at all.

Unless they appear on official lists, historic landscapes will continue to be overlooked when related projects are planned and reviewed, localities will not consider them in the comprehensive planning process, and state and federal reviewers may not be aware of their existence when reviewing potential impacts on historic resources. Landscape resources are particularly vulnerable when infrastructure and transportation projects are implemented and when new construction occurs. While the Intermodal Surface Transportation Efficiency Act (ISTEA) can provide incentives for historic landscape preservation projects to develop, the potential is just as great for adverse impacts to historic landscape features as a result of other projects. It is essential that landscape resources be inventoried and assessed in conjunction with projects funded under this act.

The National Park Service (NPS) is providing much-needed leadership in this area by including Cultural Landscape Reports (CLRs) as part of the required work when major projects are planned or reviewed within the park system. Similarly, the National Trust for Historic Preservation has turned increased attention to the historic landscape reports for its properties. Other managers and owners of historic properties need to be aware of the need for a comprehensive historic landscape inventory and analysis of land in their stewardship and care.

A number of other situations provide opportunities for inventorying historic landscapes. All preservation professionals should be alert to the following opportunities and include historic landscape inventory components when the following occur: a National Register nomination is developed or updated; general historic resource surveys or archaeological surveys are planned and conducted; historic preservation plans are developed; and environmental assessments are prepared in conjunction with Section 106 review and compliance.

Additionally, state and local preservation professionals can become aware of opportunities to plan and carry out specific historic landscape inventories. Maine, Rhode Island, and the District of Columbia, for example, have begun to inventory and evaluate historic landscapes through specific surveys devoted to historic landscape resources as have the cities of Kansas City, Missouri; Syracuse, New York; and Oklahoma City, Oklahoma. The Commonwealth of Virginia included such historic landscape resources as college campuses, state parks, and its capitol square in its survey of state-owned property. The NPS has initiated an internal cultural landscapes inventory. Thematic surveys at the local, state, and national levels of arboreta, zoological parks, athletic grounds and stadiums, institutional grounds, cemeteries, parkways, exhibition grounds, country clubs, hiking and equestrian trails, and other historic landscapes could reveal considerable information useful not only to specific landscape sites, but also of vital concern to the entire field of historic landscape preservation.

Although the newly published Guidelines for Treatment of Historic Landscapes provide general guidance for undertaking landscape preservation projects, a comprehensive site-specific inventory is desirable before any historic landscape treatment alternatives are undertaken. Not only does a inventory reveal essential information that may inform and influence treatment decisions and implementation, it also provides pretreatment record destined to become, in time, a useful historical document that con tributes to the landscape chronology of the site. Because all treatments--even those professionally executed with strict adherence to the Guidelines--will result in physical changes, documentation of existing conditions is essential.

Historic landscape inventories may have some surprising applications. For instance historic landscape inventories will no doubt influence the future work of some architects, landscape architects, and urban de signers. Designers working in a contextual framework look for historic precedents and clues to site history to integrate into or inform their designs.

Early architectural inventories that were conducted methodically, consistently, and according to archival standards remain valid today. Although they require periodic updating, supplementation. and reevaluation, they present a moment-in-time documentation of then existing design, materials, setting, and condition. Current and recently completed inventories may one day provide a similar record of many historic landscapes. For instance, historic contexts developed for such survey reports as those of state-owned properties in Virginia provide a relatively systematic historical overview of the landscape development of Virginia`s state parks and colleges and universities. When restorations, reconstructions, demolitions, deterioration and/or adjacent construction occur, the initial inventory photographs and forms can provide significant information about the pretreatment period. Competent archival photographic documentation accompanied by accurately labeled drawings and maps and conscientiously footnoted research reveal considerable information and provide important links to the historic landscape as it existed in the recent past. The single most important aspect of an inventory may be the actual documentation of the landscape at a single point in time. The in-depth architectural and land surveys that the NPS is currently conducting for the Presidio, for example, will serve not only as useful base information for the current cultural landscape inventory and planning activities in conjunction with the Presidio`s transfer from the United States Army to the NPS, but will also one day provide valuable documentation of the Presidio in the 1990s during its last years of use as an active military installation.


Although documenting a historic landscape in its entirety is the ideal, landscape inventories vary in scope and approach on both macroscales and microscales. The catch-up nature of many historic landscape projects means that often only a segment of the landscape will be inventoried--the portion to be affected by such a planned project as a new visitor center or the most visible portion of the landscape directly adjacent to a historic structure. Many historic landscapes, however, are actually landscapes within landscapes: an academic quadrangle within a college campus, a sculpture garden on estate grounds, a parade ground on a military base, an orchard within a farm. Just as a series of wooden stacking dolls can stand individually or stacked together, a landscape can be investigated as a total entity or in one or more component parts. The dolls` interrelationship, however, cannot be overlooked and any partial landscape inventory needs to consider the relationship of the smaller historic landscape section or zone to the larger landscape and to adjacent and related areas.

Most large historic landscapes encompass several distinct landscape zones. Inventories may include all areas or may concentrate on a limited number. If an entire landscape cannot be inventoried at one time, the relationship to the overall landscape of the subarea needs to be considered as should any adjacent or thematically related areas. Currently, the Pennsylvania Department of Transportation (PADOT) is undertaking a traffic-relief study for a ten-mile segment of road that runs through a plain-sect section of Lancaster County. To understand this the plain-sect cultural landscape of the Amish and Mennonites, PADOT is undertaking a cultural-resources study that uses the cultural landscape as the organizing approach for a thirty-square-mile area adjacent to the road segment.

Each new landscape inventory must tackle the issues of boundaries, recording techniques, how much to inventory, and whether to record all existing conditions or to establish a cutoff date. Debates may focus on the need to document the most valuable--and perhaps most threatened--resources versus the need to compile a comprehensive record of existing physical fabric. Still others will argue to record information vital to planning or related to particular projects or management issues.

At the Presidio, for example, the NPS, in planning for the transfer of the property from the United States Army, decided that a primary-overview cultural-landscape study was necessary for its initial planning effort. An appropriate level of inventory necessitated an initial subdivision of the Presidio into definable units that could be evaluated for integrity and significance. A second-phase cultural-landscape inventory undertaken as a component of a CLR provides more detailed information, which can be used as the basis for developing and evaluating appropriate landscape treatments for specific areas that may be leased to various groups and institutions after the existing military uses are discontinued.

Decisions on what to include in architectural inventories generally are based on the policies of funding sources, budget, time available, ideology, and the purpose of the inventory; similarly, there is no definitive way to determine what to include in an inventory of historic landscapes. Neither the selective nor the comprehensive approach will be appropriate in all situations. Deciding which resources to include and how to inventory landscape resources should be a function of both inventory purpose and property type.

Some historic landscape inventories may appear more complex because of the landscape`s enormity of scale and/or because of significant interrelationships with other cultural and natural resources. Most historic landscapes need to be inventoried and analyzed by interdisciplinary teams. Natural systems specialists, horticulturists, archaeologists, and others may be needed to supplement the findings of landscape architects, landscape historians, and architectural historians. Some landscape inventories may be most successful if conducted concurrently or as part of a broader, more multifaceted inventory.

The investigative team for the PADOT cultural resources study in Lancaster County, for example, is multidisciplinary. To understand fully the resident plain-sect population and its actions on the land, team members represent the disciplines of ethnography, anthropology, sociology, prehistoric archaeology, historical archaeology, history, architectural history, and historical landscape architecture. The scale of the study area also needed to be large enough to include a relevant sample of plain-sect farms and church districts.

Once the decision is made concerning what to include in the inventory, the criteria for inclusion must be delineated clearly and stated implicitly in all inventory products. Omitted or excluded elements or types of elements should be identified.


Historic landscape inventories should include both identification and analysis phases. The identification phase should involve more than taking photographs and completing forms; it also should include conducting research, developing historic contexts, and compiling a specific physical inventory of the landscape. Projects that omit preparation of historic contexts risk having insufficient or disorganized information. Contexts are especially important to landscapes that have multiple related units. The NPS has defined the San Antonio Missions Cultural Landscape Report so that the first volume provides the historical context and each subsequent volume deals with a specific historic mission.

The analysis phase should define significance, assess condition, evaluate the relationship of the historic landscape and its character-defining features to the historic contexts and determine integrity. National Register Bulletin 18: How to Evaluate and Nominate Designed Historic Landscapes and National Register Bulletin 30: Guidelines for Evaluating and Documenting Rural Historic Landscapes provide specific guidance on conducting inventories, particularly in relation to preparation of a National Register nomination.

The landscape inventory`s documentation should result in the development of an existing condition`s map/site plan indicating elements, areas, and systems identified during the site visit. Once site reconnaissance and documentation of a landscape have been completed and the area(s) and period(s) of significance determined, the landscape should be analyzed to determine which of its components, systems, and elements can be traced to the historic period(s) of significance and which, therefore, may be character-defining resources. This information should be mapped in a manner parallel to the existing-conditions mapping.

There is considerable uniformity among architectural documentation standards from state to state and among federal agencies and private preservation organizations. Comparable uniform documentation standards are desirable for historic landscapes. Noting exact photograph locations on maps and site plans and identifying the sources of all names and dates and other source materials may help future historians identify and date resources and locations. These actions are especially critical in landscape documentation because historic landscapes often lack the stable character-defining elements that architectural resources possess. The dynamic nature of vegetation and its vulnerability to disease, landscape-management practices, and natural events can result in a much changed and unrecognizable landscape scene in a very short period of time. If vegetation cannot be dated exactly, the rationale for estimating or ascribing any age or date needs to be explained. The vegetation in question may not survive to be available for examination when significant questions concerning its role in a historic landscape arise in the future. With the increasing use of computer mapping from CAD to GIS there are now easy and accurate methods of delineating on maps such information as the specific locations where photographs were taken or where diseased vegetation occurs.

Architectural resources contained within historic landscapes should not be ignored in historic landscape inventories. If an architectural inventory is being developed simultaneously, the two efforts should be coordinated. Even so, landscape inventories need to be concerned with the siting of buildings and structures, cluster arrangements, foundation plantings, views to and from buildings and structures, and other architecture-related issues. Photographic documentation should include--not avoid--buildings and structures because architectural elements are easier to locate, identify, and date.

In some instances, landscapes should be inventoried element by element; in others, by category or by subarea. In any event, recording all existing landscape features and systems is desirable. Arbitrary cutoff dates result in incomplete documentation and are risky in such a field as landscape documentation because the age of a resource is not always known.

Documentation through aerial photography is almost always an essential step in a landscape inventory. Aerial photographs help to reveal important landscape relationships not always evident on the ground and may provide important clues. Infrared photography can be helpful in revealing information concerning landscape archaeology. Landscape inventories can take advantage of up-to-date and improved technologies in color archival photography. Because color is an essential aspect of most landscapes, color photography is desirable. The development of photographic compact disks and the dye sublimation print process have resulted in long-awaited archivally stable color photography. The use of such technologies should be encouraged in landscape inventories.

The analysis should result in site plans that could range in complexity, detail, and execution from an annotated sketch map to a detailed, accurate computer-generated plan, depending on the level of the inventory`s documentation. For an individual National Register nomination--the Staunton family cemetery, an African-American rural cemetery in Buckingham County, Virginia, for example--a sketch map may be sufficient; for a study that is providing specific treatment and design guidelines--such as the C&O Canal Cultural Landscape Report-- detailed, computer-assisted mapping is desirable. The landscape analysis map can serve as a general planning and management guide that indicates which resources are character-defining and which are not. Landscapeanalysis efforts may be limited by the scale of mapping resources, the availability of historic maps and other resources, and by the size and character of the site. When mapping resources or the inventory budget are limited, it may be necessary to use a previously prepared site plan or maps as a base map for use in the landscape survey and the landscape-analysis map. Available mapping may be extremely limited in information, and several maps including different types of information may be required to create a base map. Depending on the total area of the site and the adjacent areas being surveyed and analyzed, the base map may need to be prepared on a large scale or on a small scale on a large-sheet format and reduced to fit a small-sheet format.

Typically, the final map-sheet format should be incorporated easily into a standardized survey format. All maps or graphics prepared should be archival and should include site-identification information, the north arrow, a scale, the date, the map number, the total number of maps in the set, and the identification of the person or organization preparing the mapping and analysis, and should indicate the base map source. Landscape mapping is currently in transition. Soon most professional mapping will be computer-assisted and the scales will be changed relatively easily. The data can be saved using an archival medium such as a compact disc. Many professional and government offices currently make use of such technology.

Inventories developed in the 1990s will be used by future generations of historians and designers in making determinations about the authenticity and integrity of the landscapes we record and manage today. The reports, inventory files, and other official products of these inventories should identify the basis for estimating the dates for any drawings, maps, or photographs. This information, which may be valuable to future historians and landscape architects, should not be contained only in research or field notes that may become separated from finished products. Official files and/or reports also should include legible copies of the original maps, drawings, or photographs consulted; should identify the original sources; and should reference any other documentary or oral sources that influenced these and other determinations. Scrupulously noting the dates of site visits is important so that future investigators will know what would have been visible or aboveground on that date. Even identifying weather conditions during a site visit can be important because a site visit on a cloudy day with poor visibility could result in judgments differing from those made on a clear day, especially where views, environmental conditions, and potential impacts are concerned.

Ideally, historic landscapes should be inventoried over the course of a full vegetative, climatological cycle and visited and observed during all seasons or periods of changing physical character. The impact of deciduous tree cover on significant views, the presence of some perennial plantings, and other major factors may not be observable in some seasons. Inventories made without benefit of observation during a full seasonal cycle should be identified as such.

Our individual biases as well as the limitations of the techniques and information we use to document landscapes and to form judgments about them become part of our inventories. Future technologies, refined methodologies, and more comprehensive landscape histories will reveal our inadequacies. Our value for the future may exist simply in having been present to record significant aspects of a landscape at a critical point.

Although we should allocate the time to experiment with various approaches and techniques, we must ensure that all landscape inventories are conducted to certain minimum standards. Early landscape inventories may be revised or expanded in the future, but their basic documentation should provide an accurate recording of existing materials and conditions and be as free as possible of contemporary bias. Known or suspected biases should be noted.


Analysis, the third important step in the preservation planning process for landscapes, provides a better understanding of the character of a historic landscape. A historic landscape may be analyzed and the structure of the landscape and its components and processes mapped using historic documents, photographs, plans, and drawings; landscape survey documentation, including contemporary photographs and annotated sites plans; the zoning ordinance and other regulations regarding land development; information on infrastructure and ownership patterns; such information as soil type, hydrology, geology, vegetation, and wildlife data and mapping; and other information. The analysis methodologies of National Register Bulletins 18 and 30 were designed to be flexible and can be modified to fit a range of landscape types. The level of analysis will vary according to the purpose of the study. Inventories prepared as part of a general or specific resource inventory or as part of a National Register nomination may focus on the issues of significance and integrity. Inventories undertaken in preparation for a management, planning, design, or preservation treatment project may direct most attention to the condition of existing elements and views of adjacent properties, or to key elements that could form the basis for the development of design guidelines and standards.

Although specific methodologies will vary from landscape to landscape, depending on the nature of the inventory and analysis and the purposes for which it will be used, there are some basic steps that should be followed in landscape analysis. These steps include the following:

  • Review of all available information concerning the resource, including survey documentation, primary sources, and other relevant data including ordinances and other regulations and site data;
  • Collection and review of additional data, such as that concerning related properties, as necessary;
  • A site-reconnaissance survey and the collection of additional documentation as necessary;
  • Review of all available data and development of an appropriate analysis methodology based on National Register Bulletins 18 and/or 30. Analysis of all available data. Synthesis of survey documentation and findings, research findings (including primary and/or secondary source materials), site data and physiographic mapping, and government ordinances and regulation;
  • Preparation of annotated landscape analysis sketch map(s) indicating landscape components, systems, features and elements. Annotation of map(s) indicating areas, systems, and features that have been determined to be and/or suspected of being character-defining or not. Indication of any threats to integrity need to be noted. The landscape-analysis map should indicate all extant systems, elements, features, and processes, whether character-defining or not;
  • Preparation of a narrative written summary report on the landscape analysis methodology and findings, gaps in data, and recommendations for further investigation.


Landscape inventories are undertaken with increasing frequency throughout the United States. Many state and federal agencies as well as private preservation organizations recognize the need to compile systematic inventories of landscape resources and to evaluate them for significance and integrity. This awareness is an important step in the understanding of our nation`s historic landscape resources.

Inventories constitute a vital first step in landscape preservation. If they become an end in themselves, they risk being a superfluous last step for some properties. The timing and use of such inventories is critical. Thousands of architectural inventories lie unused and ignored in file drawers, on shelves, and in computerized databases. Many architectural inventories have never realized their full potential because they were compiled after a local government`s new comprehensive plan was adopted, conducted concurrently with a capital-improvements or master plan and used to mitigate harmful impacts rather than avoid them, or simply undertaken because of a policy to inventory for the simple sake of collecting and storing information.

Landscape inventories should be integrated into overall management, planning and treatment goals, objectives, and policies if they are to escape a similar fate. To be most effective they need to be undertaken concurrently with inventories of related resources and investigated and evaluated in light of other related natural and cultural resources. When conducted in the proper sequence, inventories with other work elements and integrated with other resource inventories, inventories can provide the basis for effective planning and management and for the development and implementation of landscape preservation treatments that are resource based.

Publication Date: May/June 1993


Author(s):Genevieve P. Keller