Trails

Introduction

Designated wilderness areas offer opportunities for solitude, challenge, and connection with wild landscapes. Trails—when thoughtfully planned, monitored, and maintained—can support these opportunities while protecting natural and cultural resources.

Although trails are not specifically mentioned in the Wilderness Act, they play an essential role in wilderness stewardship. Trails can help reduce visitor impacts by guiding use away from fragile areas and minimizing social trail development. At the same time, trails and their associated features (such as bridges or signs) are considered installations under Section 4(c) of the Wilderness Act and are generally prohibited unless deemed necessary to meet the minimum requirements for preserving wilderness character.

This Toolbox provides wilderness practitioners with guidance, tools, and best practices for managing trail systems and features in designated wilderness. Whether you are evaluating an existing trail network, planning for visitor use, or considering the removal or construction of a trail feature, this resource can support thoughtful, law- and policy-aligned decision-making.

This toolbox covers:

• Evaluating trail necessity
• Managing trail features
• Monitoring trail conditions
• Addressing social trails
• Conducting Minimum Requirements Analyses (MRAs)

Legal and Policy Foundations

Understanding the legal and policy context for trails in designated wilderness is critical to making informed, compliant decisions. While trails are commonly used and often expected by visitors, their presence and development must be consistent with the Wilderness Act and agency policy.

Trails as Installations under the Wilderness Act

Section 4(c) of the Wilderness Act prohibits “installations” in wilderness areas unless they are “necessary to meet minimum requirements for the administration of the area for the purpose of this Act.”
Trails and trail features (e.g., bridges, culverts, steps, signs) are considered installations—even if they predate wilderness designation. Therefore, trails are not automatically “grandfathered in” and must be evaluated through a Minimum Requirements Analysis (MRA) to determine if they are essential to preserving wilderness character.

What Is a Minimum Requirements Analysis (MRA)?

An MRA is the process used by all four federal wilderness agencies to determine:

• Whether a proposed action (such as maintaining a trail or replacing a bridge) is necessary to preserve wilderness character
• And if so, what the minimum tool or method is to achieve that action with the least impact

MRAs are the foundation for lawful, thoughtful trail decisions in wilderness.

Note: Not all trails or features will meet the minimum requirement. In some cases, removing or abandoning a trail may better preserve wilderness character than maintaining it.

Agency Policy

Enabling Legislation and Trail Provisions

Some designated wilderness areas have enabling legislation that specifically addresses trails. While rare, these provisions can:

• Require development of a trail plan
• Authorize new trail construction under specific conditions
• Clarify expectations for trail use types (e.g., equestrian, hiking)

Unless a law explicitly allows or requires it, trail development must still follow the standard MRA process.

National Trails System Act

The National Trails System Act (NTSA) authorizes trail development in federally administered areas, including wilderness. However, it also requires that National Scenic Trails be managed in a way that:

• Maximizes recreation potential and conservation
• Aligns with the character of the landscapes through which they pass

When routing long-distance trails, managers should consider whether development inside wilderness is necessary—or if equal recreation and conservation goals can be met outside wilderness boundaries.

Agency Resources

• USFS
  • National Forest System Trails
  • FS Infra Trails Required & Recommended Data Work 2007
  • FS Trail Assessment & Condition Surveys User Guide 2009
  • FS Minimum Protocol for Social Trail Monitoring in Wilderness
• NPS
• BLM
• USFWS

Trail System Evaluation and Planning

Wilderness areas vary widely: some have extensive pre-existing trail networks, while others were designated with few or no trails. Regardless of starting conditions, managers have a responsibility to ensure that trails and trail systems in wilderness are the minimum necessary to meet the purpose of the Wilderness Act.

This section offers a framework to evaluate existing and proposed trails, always centering the question: Does this trail preserve or degrade wilderness character?

Key Evaluation Questions

When assessing a trail or trail system in wilderness, consider:

• Is the trail necessary to preserve wilderness character or meet minimum administrative needs?
• What is the degree of primitive recreation that existed at the time of designation?
• Can impacts (such as erosion or habitat disturbance) be better mitigated with or without the trail?
• Is this trail duplicative of other routes?
• Would maintaining or removing the trail better support solitude, unconfined recreation, and naturalness?

These questions are typically addressed through a Minimum Requirements Analysis (MRA).

Trails may support or degrade different qualities of wilderness character. Each quality should be evaluated individually and together:

Natural Quality

• A well-sited, single trail can reduce vegetation trampling, soil erosion, or wildlife disturbance caused by multiple user-created paths.
• Poorly located trails may accelerate erosion or introduce invasive species.

Outstanding Opportunities for Solitude or a Primitive and Unconfined Type of Recreation

• Trails concentrate use, which may reduce solitude.
• Travel without trails (cross-country) offers more challenge and self-reliance—hallmarks of primitive recreation.
• However, some trails—especially those with cultural significance or long-standing use—may help maintain traditional primitive recreation experiences.

Other Features of Value

• Trails may help protect cultural or ecological resources by guiding visitors away from sensitive sites.
• In some cases, the trail itself may be the resource—for example, prehistoric or tribal travel routes.

Managing Existing Trails

• Retain and maintain trails that support primitive recreation or mitigate biophysical damage.
• Close or rehabilitate trails that no longer meet minimum requirements or degrade wilderness character.
• Evaluate all trail features (e.g., signs, bridges) for necessity and minimum development.

Not all existing trails are necessary—and not all need to be removed. Trail-by-trail analysis is key.

Planning for New Trails

Constructing a new trail in designated wilderness is a serious decision. Under the Wilderness Act:

• New trails are only appropriate if clearly necessary to preserve wilderness character or meet enabling legislation mandates.
• The condition of the area at the time of designation sets the baseline for primitive recreation opportunity. If an area was trailless at designation, new trail construction may degrade that character.
• In rare cases, enabling legislation (or the National Trails System Act) may support new trail construction—but these actions still require an MRA.

Trail Reroutes and Alterations

Trail systems can be altered if the change:

• Reduces resource impacts (e.g., rerouting out of a riparian zone)
• Preserves the primitive recreation spectrum present at designation
• Improves sustainability without expanding system mileage or altering solitude dynamics

Closing a trail in one location and building a new one elsewhere is generally inconsistent with wilderness stewardship unless justified through a full wilderness character analysis.

Example Situations

Trail Features in Wilderness

While trails may be allowed in designated wilderness, they must be the minimum necessary to provide access and protect resources. The same principle applies to trail features—from cairns to bridges, these physical modifications must be carefully evaluated for necessity and impact.

This section explains what trail features are, how they affect wilderness character, and how to evaluate and manage them in line with the Wilderness Act and agency policy.

What Are Trail Features?

Trail features are physical components associated with trail function, safety, or navigation. They may be natural or constructed, permanent or temporary.

Common examples include:

• Signage (directional, informational, or regulatory)
• Cairns or rock markers
• Bridges and boardwalks
• Waterbars, cribbing, and retaining walls
• Steps, switchbacks, and turnpikes
• Trailhead kiosks or registers (at the boundary)

While some features are constructed with natural materials and blend into the landscape, others are more noticeable or involve nonconforming conditions like mechanized equipment or durable materials.

How Trail Features Affect Wilderness Character

Evaluating Trail Features: Minimum Requirement?

When planning or maintaining trail features, ask:

• Is this feature truly necessary to protect resources or visitor safety?
• Can the objective be met through a less obtrusive means?
• Is the design and material in keeping with the setting and wilderness values?
• Has an MRA been completed and documented?

Even “minor” trail work can have major implications for wilderness character.

Examples: Appropriate vs. Inappropriate Trail Features

Design & Maintenance Considerations

• Use native materials where possible
• Keep visibility low—features should not dominate the landscape
• Design for durability but respect natural processes
• Avoid overbuilding for convenience
• Remove or rehabilitate obsolete or excessive features

Less is more. A minimally marked and maintained trail better supports a primitive and unconfined experience.

Monitoring and Adaptive Management

Monitoring trail conditions and features in wilderness is important to preserving wilderness character and ensuring trails remain sustainable, minimally developed, and aligned with visitor use levels. Adaptive management allows wilderness managers to make informed decisions based on data and changing conditions.

Why Monitor Trails in Wilderness?

Monitoring helps managers:

• Detect biophysical impacts from designated and user-created (social) trails
• Track changes over time in trail condition, width, erosion, and resource damage
• Identify priority maintenance needs
• Support visitor use management strategies
• Evaluate the effectiveness of trail features
• Justify decisions made through Minimum Requirements Analysis

Trail Monitoring Methods

The right method depends on the purpose, available resources, and desired precision.

Monitoring Social Trails

Social (user-created) trails are a major concern in wilderness. They often develop in response to:

• Shortcutting switchbacks
• Seeking campsites or scenic views
• Inadequate signage or trail definition

Minimum protocol for social trail monitoring includes:

• Mapping and classifying the trail
• Assessing width, depth, and vegetation loss
• Determining origin and destination
• Evaluating necessity and options for closure or formalization

Adaptive Management in Action

Monitoring data is most powerful when paired with a framework for adaptive decision-making:

1. Assess current trail and visitor use conditions
2. Set desired conditions for trail quality, solitude, and resource protection
3. Monitor indicators like trail width, social trail proliferation, or erosion
4. Trigger thresholds when conditions deteriorate
5. Take action—reroute, restore, educate, or limit use
6. Evaluate whether conditions improve

This cycle allows managers to act responsively, justify actions, and uphold wilderness values over time.

Resources

Literature and Research

• Marion, J.L., Leung, Y.F., & Nepal, S.K. (2006). Monitoring Trail Conditions: New Methodological Considerations. George Wright Forum, 23(2).
• Svajda, J. et al. (2016). Trail Impact Monitoring in Rocky Mountain National Park. Solid Earth, 7, 115–128.
• Marion, J.L., Wimpey, J.F., & Park, L.O. (2011). The Science of Trail Surveys. Park Science, 28(3).
• Wimpey, J. and Marion, J. L. (2011). Formal and Informal Trail Monitoring Protocols and Baseline Conditions: Great Falls Park and Potomac Gorge. Research Report. USDI, U.S. Geological Survey.
• Leung, Y.F. et al. (2010). Developing a Monitoring Protocol for Visitor-Created Informal Trails in Yosemite National Park, USA. Environmental Management, 47, 93–106.

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