© Dan Gold

Pioneers of Wilderness Research: The Wilderness Management Research Unit

Science & Research

April 2019 | Volume 25, Number 1

by David Cole

The year 1964 was a landmark for important legislation in the United States. Among the bills passed that year was The Wilderness Act, which created a new category of public lands. Lands designated as wilderness were to be afforded the highest level of protection, even more protection than national parks and wildlife refuges. Like parks and refuges they were to be preserved in their natural condition, but above all, they were to be managed to protect their “wilderness character.” Like parks and refuges they were available for public enjoyment, as long as recreation use did not adversely affect the values for which the area was designated. They were to be used and enjoyed “as wilderness.” What did it mean to be charged with protecting wilderness character and managing for uniquely wilderness experiences? And how should one go about doing that?

The new land designation “wilderness” gave federal land managers a new and unique set of management objectives. Uncertainty about what those objectives were and how to achieve them was a problem. Prior to 1964, there were administratively designated wildernesses, open and available for recreation use. Through the 1950s and particularly the 1960s, wilderness recreation increased greatly. Heavy use resulted in significant impact on the environment (e.g., eroded trails, compacted campsites, piles of litter, and human waste problems). Increasing use meant popular destinations were often crowded and less likely to offer the outstanding opportunities for solitude that wilderness was to provide. Increasing use and impact was a cause for concern, with little clarity about the nature or seriousness of the problem and uncertainty about what to do about it. 

In response to this situation, in 1966, the Senate Appropriations Committee asked the Forest Service to develop a proposal for a wilderness management research unit, within the research branch of the Forest Service (Klade 2006). Responding to this request, the Intermountain Forest and Range Experiment Station developed a 13-page proposal that documented the challenge of wilderness management and specific research questions that needed to be addressed. It laid out a program focused on (1) the wilderness visitor, (2) plant and animal ecology in wilderness, (3) wildlife species in wilderness, and (4) insect, fire, and disease control in wilderness. It asked for an annual allocation of US$300,000 and proposed that the research be conducted at the new Forestry Sciences Laboratory, located on the University of Montana campus, in Missoula, Montana – an ideal location given its proximity to 7.3 million acres of existing or proposed wilderness (Figure 1).


Cole Fig 1

Figure 1 – The impacts associated with recreational use of wilderness are a primary concern of wilderness managers. In response to serious impacts, many wilderness areas limit group size and prohibit camping immediately adjacent to lakes.


Much of the proposal was accepted. In 1967, the new wilderness management research unit was established in Missoula. However, only $75,000 was appropriated (Lucas 1972). The first project leader was Bob Lucas, who transferred from the Lake States Forest Experiment Station in St. Paul, Minnesota. Lucas, a geographer, had conducted pioneering research on visitors to the Boundary Waters Canoe Area, a large tract of wilderness in northern Minnesota. His initial tasks were to develop a problem analysis to guide the new unit’s research program and to hire an additional scientist. For the latter, he selected George Stankey, a doctoral student in geography from Michigan State University.

The Wilderness Management Research Unit was the first research institution in the United States to focus intensively on wilderness management. For decades it remained the only research institution in the world to work exclusively on wilderness, as interest in wilderness exploded around the world and wilderness acreage in the United States increased from 9.1 million acres (3,682,639 ha) in 1964 to more than 100 million acres (40,468,564 ha) today. As such its influence around the world has been profound, arguably more influential than any other Forest Service research program of its size. The unit produced much of the pioneering and seminal research in the field, collaborating with and often funding other wilderness researchers. It defined much of the research agenda for the burgeoning wilderness management field and provided much of the raw material for training successive generations of wilderness scientists and managers.

Cole Fig 2

Figure 2 – Bob Lucas, the foremost pioneer of wilderness science, was an avid outdoorsman and wilderness advocate, as well as scientist. He worked from the unit’s beginning in 1967 until his retirement in 1988.

To describe the work and influence of this pioneering research unit, I divide the unit’s tenure into three time periods. From 1967 to 1977, Bob Lucas and George Stankey were the sole scientists in the unit. Both were social scientists, and in-house research during this period was highly focused on wilderness visitors. From 1978 to 1987, budgets increased briefly. David Cole, Randy Washburne, and Margaret Petersen joined the unit and the research agenda expanded. Randy Washburne, Margaret Petersen and George Stankey left the unit in 1982, 1984, and1987, respectively, and Bob Lucas retired in 1988. During the final period, from 1988 to 1993, the research agenda expanded further. David Cole was project leader. He was joined by Alan Watson, whom Bob Lucas hired in 1987. Alan was interested in social science issues beyond recreation visitors. Peter Landres was hired in 1992 to explore a broader range of ecological issues in wilderness. In 1993, the unit morphed into the Aldo Leopold Wilderness Research Institute (Figure 2).

Lucas and Stankey: 1967–1977

As befits the fact that wilderness science was a brand-new field of inquiry, the initial emphasis of the unit was on descriptive studies and development of and improvement in research techniques. Because there were only two scientists – both social scientists – the emphasis was on “visitor studies, use patterns, visitor characteristics, attitudes concerning wilderness, its use and management, and, particularly on the esthetic or social carrying capacity of wilderness and on management to match use to capacity” (Lucas 1972). The emphasis on visitor studies and social carrying capacity was retained throughout the 1970s but was increasingly supplemented by research on the ecological impacts of visitors.

Much of the early work of the unit appears – from the perspective of today – to be commonsense. But the unit’s research results were new knowledge and, in many cases, counter to prevailing notions. As Lucas (1972) noted, “Experienced administrative officers working with the same Wilderness sometimes disagree as to whether the area’s main use season is summer or fall, whether half or one-fifth of the visitors’ hike, how long they stay, where they go, and their estimates as to the level of use may vary by a hundred percent or more.” Even the most descriptive information went a long way toward making management more science informed.

Bob Lucas’s earliest personal research sought to refine methods for estimating recreation use in wilderness areas. He found that use estimates from trail registers were inaccurate but could be adjusted using correction factors obtained by either observing or using automatic cameras to estimate the proportion of different user types that failed to register. Some kinds of visitors – horse users, hunters, day users and teenagers – are less likely to register (Lucas et al. 1971). Much of Lucas’s empirical work in the early 1970s focused on a “baseline survey” of summer and fall visitors to wilderness and backcountry areas in Montana (Lucas 1980). He sought comparable data on users of these areas regarding activity patterns, visitor characteristics, and preferences for management, facilities, and use situations. Since these original surveys, similar visitor surveys – often using questions first developed by Lucas – have been conducted in wilderness and parks around the world, resulting in an ever-improving understanding of wilderness visitors and an increased ability to monitor and understand trends over time (Figure 3).


Cole Fig 3

Figure 3 – A wilderness visitor registers at a wilderness trailhead to receive a mail-back questionnaire – part of Bob Lucas’s early 1970s baseline study of wilderness visitors in Montana.


One finding of the baseline survey was that use distribution on trails and at campsites is very uneven. Certain places are much more crowded and heavily impacted than other places. This led to a study of the degree to which users might distribute themselves more equitably if they were given information about which trails are crowded and which ones aren’t. Lucas found that such an effort was unlikely to be effective unless visitors have information in the planning stages of their trip and unless information on more than just use levels is provided (Lucas 1981). This interest in use distribution and how it might change over time or be altered through management led Lucas to cooperate with scientists from Resources for the Future, Inc. to develop a simulation model of wilderness visitor flows (Lucas and Schechter 1977). With this tool, managers could simulate the effects of policies under consideration, such as limiting use at most trailheads, building a new trail, or the effect of an increase in amount of use. Without having to actually try out the change, managers could get an idea of what the resulting use pattern would be, what would happen to the number of encounters between parties, and how crowded camping areas would be.

In 1969, George Stankey did the fieldwork for his first research project. The resulting report on visitor perceptions of wilderness recreation carrying capacity proved to be highly insightful and influential – for its conceptualization of the issue, its methodology, and its empirical results (Stankey 1973). The study aimed to understand the nature of high-quality wilderness experiences, what characteristics of use influence experience quality, and how to manage for quality experiences. Extending the work of Lucas on perceptions of Boundary Waters Canoe Area visitors, Stankey studied visitors to the Bob Marshall Wilderness in Montana, the Bridger Wilderness in Wyoming, the High Uintas Wilderness in Utah, and the Boundary Waters Canoe Area in Minnesota. Recognizing that there are many different ideas about what constitutes a wilderness experience, Stankey reasoned that experience quality should be judged – not by the average visitor – but by those he called “purists,” those visitors whose personal definitions of what is and is not desirable in wilderness most closely match the legal framework provided by the Wilderness Act. These visitors defined a high-quality wilderness experience as one with few encounters with others, in an environment where human evidence was minimal, and where it was possible to camp far from others (Figure 4).


Cole Fig 4

Figure 4 – George Stankey washing up in camp during fieldwork for his 1969 study of the carrying capacity perceptions of wilderness visitors. He worked for the unit from 1969 until 1987.


Stankey asked visitors how they would feel about encountering an increasingly large number of other groups, in this way relating satisfaction with one’s experience to level of use. He referred to widely shared preferences as norms – both regarding the number of encounters with other groups and appropriate methods of travel and group size. Hundreds of subsequent visitor studies have taken a similar approach – often referred to as a normative approach (e.g., Vaske et al. 1986; Manning 2012). Stankey found that other characteristics of the groups encountered affected satisfaction more than the number of groups encountered. From the perspective of what we know today, this might seem obvious, but at the time this finding ran counter to the perception that defining carrying capacity was the key to management, and capacity was all about the number of visitors. Stankey found that, in addition to amount of use, visitor satisfaction was affected by method of travel, group size, and where encounters occurred. He then described a range of management actions, including restricting the number of users, that might be taken to manage wilderness within its capacity and provided data on visitor opinions about the desirability of these actions.

The wilderness visitor research of Lucas and Stankey was supplemented by several studies of ecological impacts of recreation in wilderness conducted by university cooperators. Sheila Helgath studied trail deterioration in the Selway-Bitterroot Wilderness in Idaho, finding that most trail segments were stable, although a few deteriorate rapidly, and that deterioration rates are determined more by location, design, and maintenance than by the amount of use they receive (Helgath 1975). Sid Frissell developed a campsite condition monitoring technique (Frissell 1978) and applied it to campsites at popular destinations in the Spanish Peaks Primitive Area (Frissell 1973). Both of these studies innovated techniques that have been subsequently used in scores of other areas and that continue to be used today. They also discovered new knowledge that is so fundamental that few modern recreation ecologists acknowledge who first discovered it.

Cole Fig 5

Figure 5 – The textbook, Wilderness Management, coauthored with John Hendee in 1978, represented the culmination of knowledge developed, organized, and applied during the first decade of the Wilderness Management Research Unit.

As important as their empirical research were Lucas’s and Stankey’s conceptual contributions to wilderness management (Lucas 1973) and their close cooperative work with other scientists and wilderness managers. The result was a much larger and more closely knit wilderness community than would normally have been possible given the meager investment made in the research unit. The publication of the textbook Wilderness Management (Hendee et al. 1978), in collaboration with fellow Forest Service scientist John Hendee, is a fitting culmination of the unit’s first decade. The comprehensiveness of the book reflects Lucas’s and Stankey’s work organizing the field of wilderness management, developing concepts and principles as well as their empirical research. It is strengthened by the time they spent with wilderness managers and working within the larger community of wilderness scientists they helped nurture and foster. Although the first edition of the book was written when the field was barely a decade old, it is currently in its fourth edition, and 40 years later much of the book remains as originally written (Figure 5).

Social and Ecological Science: 1978–1987

In 1978, funding for the Wilderness Management Research Unit doubled. David Cole was hired to increase the unit’s capacity to work on ecological impacts in wilderness. Randy Washburne was hired to develop support for and work on several ambitious survey projects. There were also more funds available to support cooperative research on a wider array of wilderness issues. In 1980, Margaret Petersen joined the unit to assist in technology transfer and work as junior scientist. The primary research themes of an updated work unit description were visitor studies, ecological impacts of recreation, and improving wilderness management systems. Based on the prestige they developed over the preceding decade, requests for Lucas’s and Stankey’s time increased greatly. The wilderness concept was spreading globally. As the only research institution in the world devoted exclusively to wilderness management, international requests for guidance and visits increased along with similar domestic requests (Figure 6).

Cole Fig 6

Figure 6 – Randy Washburne, shown here measuring soil infiltration rates on campsites in the Eagle Cap Wilderness, worked for the unit from 1978 to 1982.

During this period, much of Bob Lucas’s time went into administrative tasks. However, he continued empirical research on use measurement techniques, finding that self-issued permits provided better data than trailhead registers (Lucas and Kovalicky 1981). He oversaw research that Margaret Petersen conducted, demonstrating that trail registration compliance could be increased by locating registers up the trail and including a sign with reasons for registering (Petersen 1985). In 1982, he repeated the survey of Bob Marshall Wilderness visitors first conducted in 1970, providing the first systematic information on trends in wilderness visitors and visits (Lucas 1985). He developed the first in-depth discussion of trends in wilderness visitation, concluding that the rate of increase in wilderness visitation has slowed and use of many areas, particularly in national parks, has declined (Lucas 1989). He also wrote and spoke about his concern for increased regulation in wilderness and its effect on freedom and spontaneity (Lucas 1982).

By this time, George Stankey had largely shifted away from empirical science. Requests for his expertise came from around the world, and, during this period, he spent two years in Australia, teaching classes and working with the New South Wales National Parks and Wildlife Service. When in Missoula, much of Stankey’s effort went into two planning frameworks that proved to be highly influential. With Roger Clark, he expanded on the notion of the value of diversity in recreation experience to operationalize the framework referred to as the Recreation Opportunity Spectrum (Clark and Stankey 1979). Along with Sid Frissell, David Cole, Bob Lucas, Randy Washburne, and Margaret Petersen, he also worked to operationalize a process for dealing with recreational carrying capacity – a process that came to be known as Limits of Acceptable Change (LAC) (Stankey et al. 1985).

The genesis of this project was a request, in 1979, from Tom Kovalicky, deputy supervisor of the Flathead National Forest, to work with managers of the Bob Marshall Wilderness on some sort of demonstration of innovative wilderness management. At the same time, the research unit was being barraged with requests for help in dealing with carrying capacity. Managers sought something more than a list of factors to consider when grappling with the issue; they wanted a step-by-step process. Developing and applying such a process seemed a good idea for the demonstration project. The project took six years to complete and represented the largest outlay of time and resources in the history of the unit. All the scientists were involved, working to develop and publish the framework, conduct empirical studies of visitors and impacts, and work with managers on the LAC plan for the Bob Marshall Wilderness Complex. Following development of the framework, years were spent training agency personnel in its application. The LAC framework proved to be highly influential, providing the conceptual basis for a series of similar frameworks developed both for other applications and around the world. Bob Lucas stated that by turning “what had long been referred to as carrying capacity into a practical management tool,” development of LAC was the research unit’s “major accomplishment” (Klade 2006, p. 109).

Cole Fig 7

Figure 7 – David Cole, shown here in Torres del Paine National Park teaching Chilean park managers about the impacts and management of recreation use, was hired in 1978.

The addition of David Cole on temporary assignment, in 1978, allowed the unit to balance its work on wilderness visitors with work on ecological impacts. Cole’s initial assignment was to develop a program of work on recreation impacts in wilderness, based on a survey of existing literature. By 1978, a number of relevant studies had been conducted, but few researchers had conducted more than one study. Existing knowledge, therefore, was disparate and unorganized; it was not cumulative and seldom applied to wilderness management problems. One of his first products was an annotated bibliography of more than 300 previous studies (Cole and Schreiner 1981). Synthesis of this information and its organization into a coherent field of recreation ecology followed, most notably in a state-of-knowledge review (Cole 1987a), the first textbook on recreation ecology, Wildland Recreation: Ecology and Management (Hammitt and Cole 1987) and a number of book chapters, including one in the second edition of the text Wilderness Management (Cole 1990). Parallel to the early work of Bob Lucas on improving use measurement techniques, Cole developed monitoring techniques for campsites and trails in wilderness (Cole 1983; Cole 1989a). Using these techniques, he documented trends in impact – in some cases over periods up to 32 years (Cole 2013) (Figure 7).


Cole Fig 8

Figure 8 – Margaret Petersen, shown here measuring vegetation cover on campsites in the Bob Marshall Wilderness, worked for the unit from 1980 to 1984.


In a manner similar to Stankey’s work on visitor experiences, Cole identified the use factors that influence the nature and magnitude of ecological impact: amount, type, timing, location, and geographic distribution. He systematically studied the influence of each of these factors in a variety of environmental settings across the country, using a combination of experimental techniques and examination of existing recreation sites. Most of this work was conducted on campsites, but he also worked on trails. He studied the disturbance process and the rate at which impact occurred, using experimental application of trampling and camping in previously undisturbed environments. He studied rates of recovery in places where recreation use was curtailed. Many of the fundamental principles of recreation ecology emerged from this work. Cole found that the relationship between amount of use and impact is generally curvilinear; a little use causes substantial impact, with higher levels of use having less effect (Cole 1982). He found that impact almost always occurs rapidly; recovery rates are more variable but almost always slower than rates of impact (Cole and Ranz 1983). He found that vegetation in forests was often more fragile than that in meadows, even at high elevations (Cole 1987b). He emphasized the management implications of these studies, pointing out how results were often counter to prevailing wisdom. Impacts are usually minimized by concentrating rather than dispersing use. Resting and rotating sites – allowing them to recover – is usually a futile strategy. Recreation impacts may be more unsightly in meadows than in forests, but meadows are generally not more fragile.

Beyond Wilderness Recreation: 1988–1993

In 1987, George Stankey resigned from the Forest Service, returning to Australia to teach. Funding was sufficient to hire David Cole into a permanent position and to hire Alan Watson into George Stankey’s position as a social scientist. Bob Lucas retired in 1988, and David Cole was appointed project leader. For a long time, Bob Lucas had been interested in information and education as an alternative to regulation. So in the mid-1980s, the unit began to devote substantial resources to low-impact education – improving the accuracy of message content and increasing the effectiveness of communication channels. Much of this was spurred by a trip organized by the National Outdoor Leadership School (NOLS) in 1985 that Bob Lucas and David Cole attended. On that trip, NOLS and the Forest Service agreed to collaborate to improve the content of low-impact educational messages and assure that they were consistent with science, a project that David Cole undertook. He collected brochures, pamphlets, articles, and other examples of recommended low-impact practices from management agencies around the country. He compared them to each other, finding they were frequently contradictory. He evaluated them in the light of existing research and distilled them into a consistent set of science-based messages. This work was summarized in a handbook on low-impact practices (Cole 1989b), a revision of the NOLS Conservation Practices, and Soft Paths, the first book-length treatment of what came to be called Leave-No-Trace (LNT) practices (Hampton and Cole 1988). Subsequently, a video version of Soft Paths was produced, containing the first version of Leave-No-Trace principles, principles that have since spread around the world, being found, for example, on hangtags on recreational equipment. Interagency brochures were produced, training sessions were held, and ultimately a nonprofit organization, Leave-No-Trace, Inc. was created to further this work (Cole 2018).

Work on communication methods was more limited, and much of it was conducted by cooperators with funding from the research unit. David Cole collaborated with Steve McCool and Tim Hammond to assess the effectiveness of posting LNT messages on trailhead bulletin boards. They found that as the number of messages increased, the attention devoted to each message declined, as did the ability to retain message content. Consequently, hikers exposed to eight messages could not identify any more of the agency-recommended practices than those exposed to only two messages (Cole et al. 1997). In a subsequent experiment, Cole (1998) found that simply asking people to take the time to read messages, in a banner above the messages, doubled the length of time they attended to the messages.

Around 1990, after the departure of Bob Lucas and with the hiring of Alan Watson, research emphases shifted again. Basic research on ecological impacts and experiential quality and the factors that influence them was to continue, but there was to be new emphasis on understanding visitor conflict and on trends in visitors and impacts. The effectiveness of management techniques was to be evaluated, particularly in places that receive concentrated use, and, given widespread interest in the LAC process, research was to be conducted on appropriate indicators and standards and cost-effective techniques for monitoring them. Given the latter emphasis item, Peter Landres was hired in 1992 to increase the capacity of the unit to work on ecological issues other than recreation.


Cole Fig 9

Figure 9 – In 1988, Alan Watson was hired to continue the social science agenda of the departed George Stankey and the soon-to-retire Bob Lucas. He broadened the array of social science issues that were studied.


With the addition of Alan Watson, in-house empirical social science research increased dramatically. Moreover, with the retirement of Bob Lucas, there were substantial funds for extramural research. Perhaps after two decades the era of pioneering research was over, but this was a period of substantial research output by the unit. The first empirical study Watson undertook, in cooperation with Joe Roggenbuck and Dan Williams from Virginia Tech, was a study of visitors to three wildernesses in the South: Caney Creek in Arkansas, Cohutta in Georgia, and Upland Island in Texas (Watson et al. 1992). Besides collecting baseline information on visitors to wildernesses in a region and in ecosystem types that had not been studied before, a major focus of the study was to provide scientific input to the selection of indicators and standards, as part of the LAC process. Visitors were asked their opinions regarding which attributes of wilderness have the most impact on their experience. Littering and damage to trees in campsites, noise, and seeing wildlife were found to be very important influences on wilderness experiences. Less important were the number of encounters with other people, although campsite encounters were more important than trail encounters (Roggenbuck et al. 1993). Regarding standards for acceptable wilderness conditions, there was broad agreement across wilderness areas. However, there was little shared agreement on appropriate conditions within each wilderness, suggesting the value of managing different zones within wilderness to different standards. It also suggests caution in using visitor opinions to set standards as “the task of making a numerical judgement regarding acceptable social encounter levels may be too abstract or hypothetical to result in a meaningful standard” (Williams et al. 1992, p. 755) (Figure 9).

In 1990, Watson started field studies of conflict between horse users and hikers in the John Muir and Sequoia-Kings Canyon Wildernesses in California and the Charles Deam Wilderness in Indiana. Twenty years earlier, George Stankey had found conflict between horse users and hikers, with hikers being more bothered by meeting horse groups than they were meeting other hikers (Stankey 1980). Watson et al. (1993; 1994) sought to explore the nature of this conflict in more detail. They employed multiple measures of conflict, evaluations of whether encounters were disliked, and evaluations of whether one’s experience goals were interfered with due to encounters. They also examined the extent to which four potential determinants of conflict (definition of place, specialization level, focus of trip/expectations, and lifestyle tolerance) predicted degree of conflict. They learned a lot, particularly about what predisposes visitors to experiencing conflict. Most fundamentally, hikers who dislike meeting horses in wilderness believe that horses are inappropriate in wilderness. They “also are not as likely to accord high status to horse users, have stronger relationships with the wilderness, and place more value on the opportunities for solitude than those who do not dislike horses” (Watson et al. 1993, p. 32) (Figure 10).


Cole Fig 10

Figure 10 – In early research, Alan Watson conducted detailed studies of the nature of the conflict between hiking and horse groups that George Stankey had identified 20 years before.


Watson and Cole collaborated on several projects. To complement handbooks on monitoring campsites and trails, a handbook on use estimation was produced (Watson et al. 2000). To extend the work on visitor trends begun by Lucas, in 1990 and 1991 visitor surveys were repeated in three wilderness areas that had initially been studied between 1969 and 1978: the Boundary Waters Canoe Area in Minnesota, Desolation Wilderness in California, and Shining Rock Wilderness in North Carolina (Cole et al. 1995). Analysis of trends showed that characteristics of the people who visit wilderness changed more consistently than the types of trip they take, their evaluations of conditions, or their preferences for conditions and management. In particular, visitors were older, more highly educated, more likely to be female, and more likely to have visited other wildernesses. Watson utilized data from the Desolation Wilderness, where permits are required, to explore characteristics of people who entered the area without a permit (Watson 1993). He used data from the Boundary Waters to explore solitude opportunities there (Watson 1995).

The final collaborative project, which also involved Troy Hall from Virginia Tech, was a study of high-use destination areas a short distance from trailheads and close to large urban areas. Such places are generally highly crowded and impacted; they continue to have the same problems and concerns that first surfaced in the 1960s and spurred creation of the Wilderness Management Research Unit. Similar to the LAC project earlier, a major goal of the project was to bring both ecological and social science to bear on these issues, seeking increased insight into how to manage such places. Work was conducted in six lake basins in the Alpine Lakes, Mount Jefferson, and Three Sisters Wildernesses in Washington and Oregon. Recreation impacts on system trails, user-created trails, campsites, and lakeshores were quantified, as were encounters between groups –during the day and in the evening, on the trail, and at the destination. Exit interviews were conducted with visitors to explore who they were, what they encountered, their responses to what they encountered, and their management preferences.

Not surprisingly, encounter rates in these destination areas were extremely high, clearly exceeding what most visitors preferred. Ecological impacts were also substantial, although generally not higher than has been reported elsewhere. Most visitors expected to have numerous encounters and were not bothered by their experience. They noticed impacts and reported that impacts detracted from their experience. Few visitors supported reducing use levels – the most effective means of reducing encounters – but were highly supportive of site management approaches to limiting impact (Cole et al. 1997). Study findings influenced a new wilderness recreation management strategy developed by the Forest Service – one that embraced the oft-lauded approach of internal zoning (Oye 2001) – as well as wilderness planning in the Pacific Northwest, at wildernesses such as Mt. Hood and Alpine Lakes (Figure 11).

David Cole’s personal research focused on trend studies and further exploring the relationship between amount of use and amount of impact, in environments that vary in their durability. Studies indicated that trails were generally stable, although some segments are prone to rapid deterioration (Cole 1991). Most campsites – once they have been repeatedly used – are also relatively stable (Cole and Hall 1992). Campsite impact during the 1970s and 1980s often increased greatly, but more from the proliferation of new campsites than the deterioration of existing ones (Cole 1993). This work had important implications both for wilderness management and Leave-No-Trace practices. In popular places, it is important to concentrate use on a few established sites that rangers keep as small, clean, and attractive as possible. In little-used places, use should be dispersed, places where incipient impact is apparent should be avoided, and rangers should try to eliminate evidence of use and impact.


Cole Fig 11

Figure 11 – A major research focus for the unit in the early 1990s was management of high-use destinations in wilderness. Wilderness areas close to large urban areas experienced ever-increasing use, particularly by day visitors: informal trailing around Rampart Lakes in the Alpine Lakes Wilderness.


To extend experimental methodologies, Cole worked with Neil Bayfield, the Scottish ecologist who pioneered experimental studies of recreation impact in the 1960s. They developed a standardized method for conducting trampling experiments that would facilitate the comparability of trampling experiments, studies that were increasingly common around the world (Cole and Bayfield 1993). These methods were applied to 18 vegetation types, in Washington, Montana, Colorado, New Hampshire, and North Carolina. Camping impacts were also explored experimentally by directing people to camp on previously unused sites in varied vegetation types (Cole 1995c). Results showed that vegetation types growing in close proximity to each other can vary at least 30-fold in durability (Cole 1995a). The ability to resist being damaged by trampling was often negatively correlated with the ability to recover from damage (Cole 1995b), and it was possible to predict the resistance and resilience of vegetation by examining plant morphological characteristics. These results added to knowledge about where managers should locate facilities and what visitors should be told, in Leave-No-Trace messages, about more durable routes over which to travel and camp (Figure 12).

Cole Fig 12

Figure 12 – Trampling experiments complemented studies of established recreation sites to better describe the relationship between use and impact, rates of impact and recovery, and how impact and recovery vary among vegetation types.

A quarter century after establishment of the Wilderness Management Research Unit, the program still did not have sufficient funding to work on the array of research needs identified in the 1966 proposal to Congress. Cole (1994) developed a tool, the threats matrix, to clarify the breadth of threats to wilderness that were of concern and the variety of wilderness values at risk. He worked to identify scientists who could contribute new types of expertise to wilderness management. He worked with Mitch McClaran on issues related to meadow management and packstock grazing (McClaran and Cole 1993). He recruited and funded Rick Knight at Colorado State University to synthesize knowledge about recreation impacts on wildlife, resulting in the first book on the topic (Knight and Gutzwiller 1995).

Cole Fig 13

Figure 13 – Peter Landres was hired in 1992 to expand the ecological capacity of the unit. Much of his work focused on wilderness monitoring.

The hiring of ecologist Peter Landres in 1992 also reflected this interest in expanding the array of issues the unit could explore by expanding its skill set. Much of Landres’s time during the final year the research unit existed was devoted to developing a research agenda for ecological work beyond recreation. He collaborated with David Cole on a further elaboration of threats to wilderness ecosystems (Cole and Landres 1996) and a chapter on indirect threats of recreation to wildlife (Cole and Landres 1995), ultimately focusing his work on monitoring (Figure 13).

In 1992, Congressman Bruce Vento, concerned that agencies were not giving wilderness management the attention it deserved, introduced a Forest Service Wilderness Management Act in Congress. Among other things, the act called for creation of an interagency Aldo Leopold Wilderness Research Institute, to be located in or near Missoula, Montana. Although the bill was never enacted, Forest Service Research decided to administratively create such an institute by assimilating the Wilderness Management Research Unit, its personnel and resources, and then seeking to attract additional resources to expand the program from there. In 1993, the institute was dedicated, and 26 years after it was created, the Wilderness Management Research Unit ceased to exist.


Although it only existed for 26 years and usually had a staff of only two or three scientists, the legacy of the Wilderness Management Research Unit is profound. Staff scientists organized and gave structure to two fledgling disciplines – wilderness science and recreation ecology. They developed and refined sampling protocols and research methods for both these fields, protocols and methods that have been repeated in hundreds of subsequent studies. They coauthored the first textbooks in these fields, as well as the first book devoted exclusively to Leave-No-Trace practices. The science being done moved from basic observation, description, and organization to ever more sophisticated theory and hypothesis testing. With collaborators they developed two of the most important recreation planning frameworks, the Recreation Opportunity Spectrum and Limits of Acceptable Change. The arc of the unit’s contributions to knowledge can be traced from the pioneering work of two social scientists, to the seminal recreation ecology work of the unit’s second decade, to the increasingly diverse and productive agenda that was taken on in the final years and is being carried on by the Aldo Leopold Wilderness Research Institute.

As important as their contributions to knowledge was their attention to building and nurturing a collegial and vibrant network of wilderness scientists and managers. Staff scientists mentored young scientists, provided funding for research projects, collaborated with others, organized and attended conferences and workshops, and interacted frequently with field managers and rangers all over the country. They attended and gave talks at international wilderness conferences, expanding the collaborative network further. Most of the first few generations of wilderness scientists and recreation ecologists worked with, were funded by, or otherwise collaborated with unit scientists, leaving them profoundly influenced by those interactions. The ultimate legacy of the Wilderness Management Research Unit is this network of scientists and managers working on wilderness issues, made wiser and more informed by the work that was done by this small group of scientists.

DAVID N. COLE is emeritus scientist with the Aldo Leopold Wilderness Research Institute. He retired in 2013 after a 35-year career as a wilderness scientist. Since his retirement he has been developing a History of Wilderness Science section on the Leopold Institute website, with interviews of pioneering wilderness scientists and papers documenting the history of wilderness science.


Clark, R. N., and G. H. Stankey. 1979. The Recreation Opportunity Spectrum: A Framework for Planning, Management, and Research. General Technical Report PNW-98. Portland, OR: USDA Forest Service, Pacific Northwest Research Station.

Cole, D. N. 1982. Wilderness Campsite Impacts: Effect of Amount of Use. Research Paper INT-284. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1983. Assessing and Monitoring Backcountry Trail Conditions. Research Paper INT-303. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1987a. Research on soil and vegetation in wilderness: A state-of-knowledge review. In Proceedings, National Wilderness Research Conference: Issues, State-of-Knowledge, Future Directions, comp. R. C. Lucas (pp. 135–177). USDA Forest Service General Technical Report INT-220. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1987b. Effects of three seasons of experimental trampling on five montane forest communities and a grassland in western Montana, USA. Biological Conservation 40: 219–244.

———. 1989a. Wilderness Campsite Monitoring Methods: A Sourcebook. General Technical Report INT-259. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1989b. Low-Impact Recreational Practices for Wilderness and Backcountry. General Technical Report INT-265. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1990. Ecological impacts of wilderness recreation and their management. In Wilderness Management, 2nd ed., ed. J. Hendee, G. Stankey, and R. Lucas (pp. 425–466). Golden, CO: North American Press.

———. 1991. Changes on Trails in the Selway-Bitterroot Wilderness, Montana, 1978–89. Research Paper INT-450. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1993. Campsites in Three Western Wildernesses: Proliferation and Changes in Condition Over 12 to 16 Years. Research Paper INT-463. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1994. The Wilderness Threats Matrix: A Framework for Assessing Impacts. Research Paper INT-475. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1995a. Experimental trampling of vegetation. I. Relationship between trampling intensity and vegetation response. Journal of Applied Ecology 32: 203–214.

———. 1995b. Experimental trampling of vegetation. II. Predictors of resistance and resilience. Journal of Applied Ecology 32: 215–224.

———. 1995c. Disturbance of natural vegetation by camping: Experimental applications of low-level stress. Environmental Management 19: 405–416.

———. 1998. Written appeals for attention to low-impact messages on wilderness trailside bulletin boards: Experimental evaluations of effectiveness. Journal of Park and Recreation Administration 16: 65–79.

———. 2013. Changing Conditions on Wilderness Campsites: Seven Case Studies of Trends Over 13 to 32 Years. General Technical Report RMRP-GTR-300. Fort Collins, CO: USDA Forest Service, Rocky Mountain Research Station.

———. 2018. Leave No Trace: How it came to be. International Journal of Wilderness 24(3): 54–65.

Cole, D. N., and N. G. Bayfield. 1993. Recreational trampling of vegetation: Standard experimental procedures. Biological Conservation 63: 209–215.

Cole, D. N., and T. E. Hall. 1992. Trends in Campsite Condition: Eagle Cap Wilderness, Bob Marshall Wilderness, and Grand Canyon National Park. Research Paper INT-453. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Cole, D. N., T. P. Hammond, and S. F. McCool. 1997. Information quantity and communication effectiveness: Low impact messages on wilderness trailside bulletin boards. Leisure Sciences 19: 59–72.

Cole, D. N., and P. B. Landres. 1995. Indirect effects of recreation on wildlife. In Wildlife and Recreationists:

Coexistence Through Management and Research, ed. R. L. Knight and J. J. Gutzwiller (pp. 183–202). Covelo, CA: Island Press.

Cole, D. N., and P. B. Landres. 1996. Threats to wilderness ecosystems: Impacts and research needs. Ecological Applications 6: 168–184.

Cole, D. N., and B. Ranz. 1983. Temporary campsite closures in the Selway-Bitterroot Wilderness, Montana. Journal of Forestry 81: 729–732.

Cole, D. N., and E. G. Schreiner. 1981. Impacts of Backcountry Recreation: Site Management and Rehabilitation – an Annotated Bibliography. General Technical Report INT-121. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Cole, D. N., A. E. Watson, T. E. Hall, and D. R. Spildie. 1997. High-Use Destinations in Wilderness: Social and Biophysical Impacts, Visitor Responses, and Management Options. Research Paper INT-RP-496. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Cole, D. N., A. E. Watson, and J. W. Roggenbuck. 1995. Trends in Wilderness Visitors and Visits: Boundary Waters Canoe Area, Shining Rock, and Desolation Wildernesses. Research Paper INT-RP-483. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Frissell, S. S. 1973. The impact of wilderness visitors on natural ecosystems. Unpublished paper on file at USDA Forest Service, Aldo Leopold Wilderness Research Institute, Missoula MT.

———. 1978. Judging recreation impacts on wilderness campsites. Journal of Forestry 76: 481–483.

Hammitt, W. E., and D. N. Cole. 1987. Wildland Recreation: Ecology and Management. New York: Wiley.

Hampton, B., and D. Cole. 1988. Soft Paths: How to Enjoy the Wilderness Without Harming It. Harrisburg, PA: Stackpole Books.

Helgath, S. F. 1975. Trail Deterioration in the Selway-Bitterroot Wilderness. Research Note INT-193. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Hendee, J. C., G. H. Stankey, and R. C. Lucas. 1978. Wilderness Management. Washington, DC: US Government Printing Office.

Klade, R. J. 2006. Building a Research Legacy: The Intermountain Station: 1911–1997. General Technical Report RMRS-GTR-184. Fort Collins, CO: USDA Forest Service, Rocky Mountain Research Station.

Knight, R. L., and K. J. Gutzwiller. 1995. Wildlife and Recreationists: Coexistence Through Management and Research. Washington DC: Island Press.

Lucas, R. C. 1972. Forest Service wilderness research – the problem, research to date, and needed research. Unpublished paper on file at USDA Forest Service, Aldo Leopold Wilderness Research Institute, Missoula MT.

———. 1973. Wilderness: A management framework. Journal of Soil and Water Conservation 28: 150–154.

———. 1980. Use Patterns and Visitor Characteristics, Attitudes, and Preferences in Nine Wilderness and Other Roadless Areas. Research Paper INT-253. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1981. Redistributing Wilderness Use Through Information Supplied to Visitors. Research Paper INT-277. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1982. Recreation regulations – when are they needed? Journal of Forestry 80: 148–151.

———. 1985. Visitor Characteristics, Attitudes, and Use Patterns in the Bob Marshall Wilderness Complex, 1970–82. Research Paper INT-345. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1989. A look at wilderness use and users in transition. Natural Resources Journal 29: 41–55.

Lucas, R. C., and T. J. Kovalicky. 1981. Self-Issued Wilderness Permits as a Use Measurement System. Research Paper INT-270. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Lucas, R. C., and M. Schechter. 1977. A recreational visitor travel simulation model as an aid to management planning. Simulation and Games 8: 375–384.

Lucas, R. C., H. T. Schreuder, and G. A. James. 1971. Wilderness Use Estimation: A Pilot Test of Sampling Procedures on the Mission Mountains Primitive Area. Research Paper INT-109. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Manning, R. E. 2012. Frameworks for defining and managing the wilderness experience. In Wilderness Visitor Experiences: Progress in Research and Management, comp. D. N. Cole (pp. 158–176). Proceedings RMRS-P-66. Fort Collins, CO: USDA Forest Service, Rocky Mountain Research Station.

McClaran, M. P., and D. N. Cole. 1993. Packstock in Wilderness: Use, Impacts, Monitoring, and Management. General Technical Report INT-301. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Oye, G. 2001. A new wilderness recreation strategy for national forest wilderness. International Journal of Wilderness 7: 15–16.

Petersen, M. E. 1985. Improving Voluntary Registration Through Location and Design of Trail Registration Stations. Research Paper INT-336. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Roggenbuck, J. W., D. R. Williams, and A. E. Watson. 1993. Defining acceptable conditions in wilderness. Environmental Management 17: 187–197.

Stankey, G. H. 1973. Visitor Perception of Wilderness Recreation Carrying Capacity. Research Paper INT-142. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1980. A Comparison of Carrying Capacity Perceptions Among Visitors to Two Wildernesses. Research Paper INT-242. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Stankey, G. H., D. N. Cole, R. C. Lucas, W. E. Petersen, and S. S. Frissell. 1985. The Limits of Acceptable Change (LAC) System for Wilderness Planning. General Technical Report INT-176. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Vaske, J., B. Shelby, A. Graefe, and T. Heberlein. 1986. Backcountry encounter norms: Theory, method and empirical evidence. Journal of Leisure Research 18: 137–153.

Watson, A. E. 1993. Characteristics of Visitors Without Permits Compared to Those with Permits at the Desolation Wilderness, California. Research Note INT-414. Ogden, UT: USDA Forest Service, Intermountain Research Station.

———. 1995. Opportunities for solitude in the Boundary Waters Canoe Area Wilderness. Northern Journal of Applied Forestry 12: 12–18.

Watson, A. E., D. N. Cole, D. L. Turner, and P. S. Reynolds. 2000. Wilderness Recreation Use Estimation: A Handbook of Methods and Systems. General Technical Report RMRS-GTR-56. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Watson, A. E., M. J. Niccolucci, and D. R. Williams. 1993. Hikers and Recreational Stock Users: Predicting and Managing Recreation Conflicts in Three Wildernesses. Research Paper INT-468. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Watson, A. E., M. J. Niccolucci, and D. R. Williams. 1994. The nature of conflict between hikers and recreational stock users in the John Muir Wilderness. Journal of Leisure Research 26: 372–385.

Watson, A. E., D. R. Williams, J. W. Roggenbuck, and J. J. Daigle. 1992. Visitor Characteristics and Preferences for Three National Forest Wildernesses in the South. Research Paper INT-455. Ogden, UT: USDA Forest Service, Intermountain Research Station.

Williams, D. R., J. W. Roggenbuck, M. E. Patterson, and A. E. Watson. 1992. The variability of user-based social impact standards for wilderness management. Forest Science 38: 738–756.

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