2.5 Protect Park Resources 


  • identify the key features that affect trail potential,
  • identify environmentally sensitive areas,
  • assess general terrain and soil conditions,
  • assess general wildlife habitat and species information,
  • determine the limits of acceptable change in the area where the trail is planned,
Trail construction, use and maintenance will affect natural and cultural resources in the park. If the anticipated changes are unacceptable, modify the trail plan, the type of uses, or abandon the proposal altogether. See Section X for a description of environmental protection techniques. 

Carrying capacity and the limits of acceptable change (L.A.C.) are two techniques often applied in trail planning to minimize adverse impacts on the environment and on the recreation experience of trail users. This manual may be used without applying the L.A.C. method, but trail planners will find the approach to be useful and efficient. The L.A.C. outline in this manual is a summary of a comprehensive process originally developed for application in United States wilderness areas. Refer to the L.A.C. references in the Appendix for a complete description of the method. 

2.5.1 What is Trail Carrying Capacity? 

The "carrying capacity" of a trail is now more often described as the "limits of acceptable change". The literature identifies four distinct types of carrying capacity: 

  • ecological (eg. vegetation, wildlife, soils)
  • social (eg. the perception of crowding)
  • spatial or physical (eg. ability of hilly forested terrain to absorb the number of users)
  • facility (design capacity, eg. parking lot)
The recreational carrying capacity of a trail can be defined as: "The level of use an area (trail) can withstand while providing a sustained quality of recreation." Recreation carrying capacity is: 
  • a values based approach, with qualitative criteria,
  • a management decision to determine what level of trail use will produce "satisfaction" among users with known impacts on the resources and users,
  • usually focused on numbers of users,
  • based on visible indicators, such as trail erosion, stream pollution, soil compaction, set by management objectives,
  • sometimes more a case of the kind of use, behaviour of users, timing and distribution of use,
  • difficult to use because of its focus on numbers of users combined with use rationing techniques,
2.5.2 Consider the "Limits of Acceptable Change" Approach 

The Limits of Acceptable Change (L.A.C.) approach used in this manual was adapted from the B.C. Forest Service Training Manual (Rutledge, 1992) and the work of the U.S. Forest Service. The L.A.C. approach may be suitable for a range of park planning and design projects, but is described here as a way to help protect park resources and maintain high quality recreation experiences on park trails. The "limits of acceptable" (LAC) change approach: 

  • is an alternative to the carrying capacity approach,
  • assumes that change to an area will occur, so the goal is to manage the rate and type of change within acceptable levels,
  • relies on setting management objectives and describing the kind of recreation opportunities that will be provided,
  • identifies the ecological and social factors that are likely to change, then selects indicators that can be used to measure the change,
  • sets a standard for the change in each indicator, defining what is an acceptable or unacceptable change,
  • uses these standards as reference points to see if the management objectives are being met,
  • uses standards as "triggers" that can tell a manager when to take mitigating action,
  • allows for many kinds of management responses, not just limiting use,
  • is based on trying to provide the best possible conditions,
  • has a strong public participation component, is based on early participation by potential users, and tends to result in decisions that are open and accountable.
The L.A.C. concept: 

What conditions are acceptable, and if we haven't achieved them, what do we need to do? 

The L.A.C. method may be applied to all aspects of trail planning, design, maintenance and monitoring. When using this manual, refer back to the L.A.C. outline when considering each step in the trail planning process. 

Step 1: Identify The Trail Development Issues 
  • identify Issues By Public, Interest Groups
  • are Existing Resources Degraded?
  • are There Special Features That Need Protection?
What Are The Existing Conditions? 
  • damaged soil and vegetation?
  • crowding, trail encounters, conflicts between users?
  • what is the condition of wildlife forage?
Assess Issues Based On These Assumptions: 
  • change is inevitable, any use will result in some impact,
  • focus on human impacts,
  • focus on changes that you can do something about,
  • remember that a variety of park recreation settings are desirable,
Priorize the Issues 
  • decide which issues are the most important, you can't deal with all of them.
Step 2: Define Recreation Opportunities by Management Zone 

Management zones are a statement of what you want to achieve. 

Wilderness Zone: 

  • no trails or few trails, often routes only, mostly undisturbed resources,
  • solitude, high risk, few encounters,
  • management emphasis on sustaining ecosystems.
Natural Environment Zone 
  • mostly unmodified natural environment, impacts visible but only at specific locations such as campsites, vegetation loss persists but natural processes minimally affected,
  • infrequent encounters with others, long trips,
  • minimum contact between agency and visitors,
  • trails maintained for light use,
  • structures provided if required, but not for user convenience.
Intensive Recreation Zone 
  • natural appearing environment,
  • environment modified but not apparent to most people,
  • most modification for user facilities,
  • more contacts with other users,
  • more day use,
  • management emphasis on sustaining natural environment and preventing conflicts between users,
  • structures are acceptable for visitor convenience,
  • trails maintained for heavy use.
Decide what the resource conditions should be in each management zone 

Step 3: Select Indicators

An indicator is a measuring stick to measure changes over time. Indicators must be:
easy to measure, 

  • specific,
  • significant,
  • sensitive to changes,
  • reliable,
  • responsive to management changes,
  • cheap to measure.
  • Select indicators to respond to issues (from Step 1).
  • Select indicators that will help with most important issues.
  • Use indicators that can be described with measurable units, so standards can be applied. For example, "poor wail condition" doesn't help. Depth of trail tread erosion, trail width, mucky sections per kilometre are more specific.
  • Use a few indicators, avoid gathering huge amounts of useless data.
Examples of indicators: 
  • Social number of incidents of vandalism,
  • reported user conflicts,
  • availability of backcountry campsites,
  • the number of informal trails created by users,
  • number of user caused fires.
  • depth of tread below ground surface,
  • braided trails,
  • standing water.
  • number of species (diversity),
  • per cent vegetation cover.
  • coliform counts,
  • potability.
Fish and Wildlife 
  • change in wildlife distribution,
  • population trend on winter ranges,
  • increase in non-native species.
  • number of incidents of wildlife harassment,
  • hiker/dog confrontations on the trail.
Step 4: Inventory Trail or Route Conditions 
  • Limit the inventory to information that can be used.
  • Gather information already collected and use what you can.
  • Identify further inventory needs.
  • Decide how to conduct inventory.
  • Train field staff.
  • Collect and analyze the data.
Step 5: Set Standards 

A standard is a condition of the indicator which triggers a management action. Standards are at the core of the L.A.C. method: they describe what is minimally acceptable, not what is desired. A standard is a contract between the manager and the public. 

  • Take action when a standard is reached.
  • Standards should be achievable.
  • Set standards in consultation with user groups.
  • The standard does not change.
Step 6: Identify Alternative Zones 
  • Map various different alternatives for zoning the trail route, or match the trail route to existing park management zones.
  • Prepare maps in consultation with user groups or let them draw their own maps. Often there will be more common ground on wilderness issues than you might expect.
  • Write a description of the general trail management theme, for example "return to natural condition as soon as possible".
Step 7: Identify Management Actions 
  • By this step you have compared existing conditions to the standards developed, and have identified where problems exist.
  • Use the standards from Step 5 to direct management actions needed to attain them.
  • Assess possible management actions in terms of their desirable outcomes and undesirable side effects. (This is similar to a cost-benefit analysis, and can include real costs like hiring staff to carry out the management action.)
  • When considering management actions, think about:

  • - effectiveness 
    - acceptability 
    - enforceability 
    - longterm commitment
Step 8: Select The Preferred Alternative 

No simple formula exists for this step, but should be based on criteria determined by managers and concerned users. Questions might include: 

  • Which groups are affected?
  • Which values are promoted and which are diminished?
  • How feasible will it be to manage the trail as prescribed?
  • What are the costs?
Step 9: Implement Management Actions 
  • Implement management actions
  • . Include a schedule for completion.
  • Prepare a monitoring plan.
  • Evaluate the success of the management actions
  • . Monitor trail sections where you know the standards will be exceeded soon, or where conditions have suddenly changed, for example with a new access point.
  • Pay particular attention to situations where it is difficult to predict the outcome.