Trail Design
The location and characteristics of a trail represent "a balance between beauty and function" (Proudman and Rajala 1981). Initial planning for any trail system requires careful evaluation of the general purpose for the trails, as well as the types of people that will use them and activities they will conduct. The options for trail development vary widely depending on these goals and functions. Common trail themes which meet landowner objectives include:
Landowners may focus on individual themes, or combine them to emphasize different educational, scenic or recreational values.
Several other important considerations in initial planning will influence general trail design. Specific site conditions or natural features on the property might be either highlighted or avoided. For example, sinkholes can provide interesting changes in vegetation and good stopping points on well-marked educational trails. On the other hand, they might represent safety hazards if unmarked and located adjacent to primitive-type riding or hiking trails. Similarly, historic farm sites are often key points of interest, but old wells or cisterns are safety hazards. Although wildlife observation may be a central theme for some trails, you may need to locate the trails away from areas on which endangered species are protected. All these examples illustrate that it is important for the landowner to identify conditions or situations that should be featured or avoided in trail design and location.
Trails on private land are frequently used only by the landowner, immediate family and friends, or groups that are granted permission to use the trails. However, some landowners also open their land for public use. If the latter is your intention, you may need to follow trail guidelines and specifications that meet requirements of the Americans with Disabilities Act (ADA). For example, under ADA, general use trails need well-packed or hard surfaces and gentle grades. These trails will preferably form a loop from start to finish, and be 1/2 to 2 miles in length. Landowners should seek professional advice on current ADA standards as they design trails that will be open to the general public.
Other considerations during initial planning may include the availability of funds for construction and maintenance, natural (on-site) materials that can be used for structures and trail surface, and building materials from commercial sources. Other resource constraints on design and function include site characteristics such as heavy brush in some areas, swamps and marshes, or railroads and fencelines. Possible limitations on trail design should be understood by the landowner prior to any detailed planning. They will influence construction options, thereby impacting costs and labor necessary to develop and maintain the trail system.
After initial planning is completed, the trail design process shifts to deciding where to locate the trail and general construction features. Important trail attributes that will be defined include the shape, or format, and the structural components of the trail corridor. Alternatives for trail format are loops, horseshoes and lines, as illustrated in the figure below.
(Courtesy of the Appalachian Mountain Club)
Loops return the trail user to the starting point without retracing part of the trail. They are good trails for nature study, day hikes, and use by both horses and hikers. Although day-use trails are generally less than 2 miles in length, longer loops can be designed for other purposes. Horseshoe-shaped trails are similar to loops except that the end points are at separated trailheads connected by easily accessible transportation. A third trail format is a line between the trailhead and destination, and users can only return to the starting point by retracing their steps. Examples range from a short access trail to a point of interest such as a lake or campsite, to the Florida Trail which extends several hundred miles across Florida.
The trail "corridor" is the total environment of the trail. It consists of: the walking surface (tread); the right-of-way (trail bed), including all area cleared for passage of the trail user; and the buffer zone, which is the area on both sides of the right-of-way that shields the trail from outside influences. Except for long-distance vistas and scenery, the trail corridor includes the immediate features that influence trail difficulty and the environment that is visible to the trail user. Thus, trail location and construction are inseparably related to the desired corridor conditions.
Once the general design and characteristics of the trail have been determined, the next step is on-the-ground location of the best route to meet the objectives and design requirements. Reconnaissance to identify and evaluate alternative routes begins with aerial photos, topographic maps, or other maps if neither of the first two are available. Aerial photos, or copies of them, are often available through ASCS, SCS, or county property appraiser offices. They help to identify exact locations of important features such as openings in forests, existing trails, old roads or railroad grades, sinkholes, and old homesites. They can be used to map vegetation types and special features on other base maps. Topographic maps provide additional information on slopes, waterways and the location of special features that might not be visible on aerial photos.
A detailed property map should be developed from, or modified by, these sources of information to include all items that might be considered in locating trail routes and that might have either positive or negative effects on trail location. Alternative routes can be drawn on the map to optimize the positive effects and minimize the negative ones.
Armed with the property map and aerial photos, the landowner should walk through all the alternative routes identified on the map. It is often helpful to conduct this "walk-through" with resource professionals who can provide valuable input and suggestions. During the on-site inspection, check all points of interest to be sure they are worthy of being featured along the trail. Also carefully check all possible water and road crossings to be sure stream banks are stable and road crossings are visible for at least 500 feet in both directions.
A variety of environmental conditions that will influence trail location can be identified in both the preliminary mapping and field evaluation. Soils with saturated conditions or high water tables need to be noted and checked after long periods of rainfall. Trail location should generally avoid such sites. Clay soils are more prone to erosion than the sandy soils that occur throughout much of Florida. Trail routes on clay soils need to be identified to plan for erosion control measures if on sloping land. Preferred soil conditions include sandy and loamy soils with no shallow hardpans. Ridges and high topographic routes generally are drier, require less construction and maintenance, and provide panoramic views. On the other hand, ravines may need to be avoided for safety and environmental protection, although they can provide points of interest with proper planning. Waterways, springs and sinkholes are often points of interest, but trail location and construction must allow for their protection. Dense vegetation in these areas is also a problem for initial construction and maintenance. Benches or terraces along waterways may be more favorable for trail location than the floodplain along streams. Access to the water is still possible by means of short spur trails. If your proposed trail routes happen to traverse moderately sloping ground, you will probably want to be sure that routes generally follow contours.
Vegetation along the proposed routes should be evaluated for both aesthetic and environmental protection concerns. For aesthetic purposes, plant diversity is often a desirable trail characteristic, and routes should be favored that expose trail users to as many different plant communities as possible. Thick understory, found near streams or ponds, may block views, decrease aesthetic values, and require more frequent trail maintenance than lighter vegetation. However, such thick vegetation can also be used to channel and contain hiker traffic, retard soil erosion (due to the abundance of roots under the tread), protect hikers from weather (eg cooling in summer), and act as a buffer between incompatible activities.
Final route selection involves connecting as many of the positive features marked on the map and avoiding as many of the negative features as possible. The route can be identified with plastic flagging at this point, which allows trail location to be adjusted during actual layout of the trail as described later in this paper. Conditions to favor in route selection include:
Avoid trail location in areas with:
| * Drainage constraints such as wet, flat, or frequently flooded
depressions (unless they are highlighted for nature study, or have crossings of some type) * Unstable or fragile soils (erosive or slides) * Steep slopes, bluffs and cliffs * Dense vegetation requiring excessive clearing and maintenance
* Vegetation and wildlife habitats that might be adversely affected
* Cultural and archeological sites that need to be protected and are not featured * Timbered areas subject to blowdown, falling limbs or other dangers * Old mine areas or other man-made hazards (wells, cisterns etc.) * Frequent stream corssings * Existing farmlands |
Trail construction involves clearing the vegetation along the right-of-way, cleaning or surfacing the tread, and building any planned structures. A variety of tools and materials can be used for these construction practices. Labor and costs will be significantly influenced by the selection of tools and materials. Be sure to carefully select the right equipment for each particular task.
Initial clearing and subsequent maintenance often requires cutting logs and various forms of vegetation. Axes, brush hooks and machetes are used for small (less than 2 inch) diameter stems and branches. They are quick and efficient, and many people have experience using them. Axes are especially useful for construction and maintenance of long distance trailsbecause of their versatility and light weight. They are also used for removing bark and for notching or flattening logs. All three of these tools generally leave pointed stubs or stumps, and if not correctly sharpened have the nasty habit of glancing off targets into shins or other objects. They should, therefore, be used with the utmost care, and protective leg guards are advisable.
Saws provide smoother cuts and are generally more efficient than axes or machetes for large diameter stems and logs. Chainsaws are, of course, the fastest, but they are heavier than the other alternatives and require more care, maintenance, and attention to safety than the others. Crosscut saws are not widely used anymore, but can be very efficient and light weight when used properly. Pruning and bow saws are the best option for many small to medium diameter stems and branches, and permit pruning branches flush with stems so as not to leave any stubs. Lopping shears and hand-held pruning shears also provide clean, flush cuts and are good for stems with diameters less than 1 inch. Gasoline-powered brush cutters or mowers, with circular blades, can be used for quick clearing of large areas, but they leave ragged cuts and stumps above ground line. Chisels and adzes should also be mentioned as cutting tools as they may be appropriate in the construction of various structures.
Another set of tools is required for removing roots and stems from treadways, excavation for sloped trails and erosion control structures, and other digging tasks. Shovels, with long or D-handles, are used primarily for moving soil or surface materials, and for digging out rocks. Mattocks, grub hoes, hazel hoes or Pulaskis can also be employed for digging roots and stones out of right-of-ways and for shaping erosion control devices such as water bars. Other related tools include fire rakes or yard rakes for leveling tread surfaces, and large crowbars for moving heavy objects (and avoiding shovel handle breaks).
Although these tools will accomplish the large majority of construction and maintenance tasks, several other tools provide specialized services. Sledge hammers, splitting mauls and wedges may be necessary for driving spikes and stakes in bridges and other structures, or for splitting logs that are used in construction. Various types of bars (peelers and bark spuds) are available for work that involves a substantial amount of bark peeling. Logs used in construction tend to rot faster if the bark is not removed. Peeling bark with axes is feasible if you have only a few trees, but it is a slow and laborious process. Finally, come-alongs, winches and timber carriers will greatly assist in moving large logs and rocks. Be careful in their use to have good connections and to not exceed weight limitations.
Trail construction often utilizes various materials for trail surfaces or borders, steps, signs, or more complex structures such as bridges. In general, natural and native materials are preferred for such purposes since they help the trail to blend with surroundings. Trail surfacing is not necessary for all trails, but should be considered for trails that will be heavily traveled or that cross poorly drained spots or clay soils that may be slippery or easily eroded. Sawdust, shavings, wood chips and mulch provide a soft surface for walking and prevent erosion, trail wear and resprouting of roots under the tread. However, they are expensive to spread on long trails since they must be transported from drop points or mulched on site. Pineneedles and regular leaf litter can provide the same effects and may already be on the trail surface, or can be collected in adjacent stands without disrupting aesthetic values along the trail. Rakes and plastic or burlap bags work well for such local collection and redistribution.
Gravel and rock are more expensive to purchase, transport and spread, but may be important in local spots of poorly drained or slippery soils. Gravel should also be considered for short trails that will receive heavy public use, if a solid packed surface will not otherwise be provided. Larger rocks may be used for a number of other trail purposes. Rocks with at least one flat surface serve as steps or stepping stones across wet areas, and more irregular shaped rocks can be used as ballast in building up trail subsurfaces or as anchors for waterbars, wood steps, bridges and other structures. Geotextiles, now widely used in road construction, can also be placed across poorly drained spots prior to gravel or rock, and will substantially reduce the amount of rock that is needed for surfacing.
Wood structures rely on either logs cut near the trail or pressure treated lumber or ties. Native logs blend nicely with trail environments and can be cut in whatever sizes are needed in trail construction. Pine, cedar and cypress logs will generally last longer than most of the hardwoods, but bark should be peeled off all logs to reduce rot and increase the useful life of the logs. Pressure-treated lumber, posts and beams have a much longer in-use life than untreated logs. However, they are obviously more expensive than using native materials and must be transported to the trail site. You may want to use them just for posts and beams that will be in contact with the soil, such as sign posts, bench supports and mud sills for bridges. If lumber has to be purchased, as for planks on bridges and boardwalks, rough sawn pressure-treated lumber should be more cost efficient because of its longer life than untreated lumber.