Walk the Walk
What good is a lovingly nurtured native, woodland landscape if it is inaccessible? Creating paving or hardscape elements within a native plant area must be done sensitively and in a style that is compatible with the organic character of the site. Once built, paving can direct foot traffic to areas away from sensitive roots and distribute the weight of visitors more evenly over the soil to protect your special plants. A walk through the woods is welcoming on a natural path.
Making the Grade
The best way to scout out the proper course for a path is to walk the site. Try to keep the path on level, open areas. When changes in grade are necessary, make them comfortable by zig-zagging the pathway slowly up or down the grade of the hill. Zig-zags don't need to be sharp. They can be winding curves that swing around special trees and carve out plant beds for sweeps of ground covers or collections of wildflowers. Steep grades and steps are uncomfortable and less interesting than paths that aimlessly wander and gradually climb up to a higher level or lazily settle down to a lower level. Flag, spray paint, or lime can be used to mark the path and visualize the final product. You can visualize the results by visiting the site and trying out ideas.
A narrowly excavated path is best in native areas. Excavation needs to be only slightly shallower than the finished depth of the paving surface. Save the topsoil for use in the garden or deposit it at the edges of the path for new planting. A two foot path will barely accommodate a single person. A four foot wide path will allow two people to walk past each other without fighting and it is the minimum path width to accommodate asphalt processing equipment. Multi-use paths are typically ten feet wide and require additional soil disturbance to provide a good sub base for paving. The more narrow the path, the less disturbance to the soil. Choosing a narrow path allows you to hand excavate.
Heavy grading equipment requires extra widths for maneuvering. Any equipment needed to complete the path will have a major impact on the site. Soil compaction can never be undone. Moving dirt by hand is really hard work, though! Early CCC trails did that, and they are amazingly sensitive to the land. In a native area, however, you might decide to accept the tradeoff of a wider path in exchange for ease of construction and accommodating more traffic.
Moving in Equipment
I once carefully plotted a pathway through a wooded hillside that lead to a historic civil war battleground. After the battle in 1865, the town had constructed a large brick reservoir in the immense hole blown out of the center of the hill when they destroyed the munitions. It could be reached by climbing up through brambles and trees to an observation point at the top. I took great care to preserve the existing vegetation, not only for aesthetic reasons, but for erosion control and preservation of the archaeological value of the hill.
The historical society was excited and in a hurry to reenact the battle scene. They asked a local contractor to build the path. He donated his work. He was a member of the historical society. He used a large backhoe to excavate the path and he was finished in two days.
Do you really want to hear the rest of this story? If not, skip to the next paragraph. Anyway, it was hard to see the flagged path and he didn’t contact me before starting, so I wasn’t there to help. The contractor left out a few zigs and a lot of zags. The hillside was denuded. The pristine state of the archaeological site was destroyed. The roots of trees holding the hillside were ripped out. The topsoil was lost after the first heavy rain. The historical society decided to fill in the reservoir with sand from the nearby river and build a replica of the original dirt fort at the top of the bald hillside. In the battle reenactment, the Civil War uniforms got a little muddy, to say the least.
My advice to you is to never, never, never get in a hurry to construct a path in a native area. Expect a lot of hand labor and avoid the use of skid loaders, backhoes, and free offers. Evaluate the path often as it is being constructed. Be patient. Paths involve hard work, heavy lifting, and lots of uncomfortable walking with loads. Plan on the construction happening in bits and pieces of time, not all at once. Enjoy the process and embrace the time and flexibility required to mold the path to the natural site.
Planning for Irrigation and Lighting and Drainage
During excavation it is a simple task to place PVC sleeves below the path to receive irrigation pipe and irrigation wiring or low voltage wiring through the subsurface at a later date. Why not plant a few three inch pipes under the trail at crucial spots and make life easier later on?
Paths, ideally, should percolate rain water in place. If a path intersects a natural surface drainage swale, it will need to bend to work with it or be bridged with a small culvert structure to go over it. This can be as simple as a yard inlet and pipe or as elaborate as a stone bridge.
The Proper Foundation
Paving needs to be placed on a solid surface. It is surprising how much soils can sag with time! The subsurface of any paved path needs to be prepared to receive people without failing under the weight of foot traffic and soil movement. Compaction of the subsurface can be done by hand or with small hand-held equipment. Hand tampers will compact the soil fairly well, but the 95% compaction required for a most stable subsurface requires a vibrator-compacting plate. This presents another tradeoff decision. If you are comfortable with the idea of repairing sunken spots regularly, then hand tamp only. If you never want to get on your hands and knees on a hard surface for repairs, then use a rented compactor.
The subbase of a path can vary. In southern climates, the heavy clay soil can act as the sub base. Before hand tamping, you can mix Portland cement into the subsurface soil at 9 parts cement to 1 part soil to make a soil cement base that will harden with the first rain. In areas with frost/heave, something more substantial is required. You need deeper excavation, a gravel sub base, and a concrete surface with reinforcement. Even with a good subbase treatment, nearby trees can grow in a way that ruffles the path surface. Different subbase treatments will still need regular maintenance.
Holding Together Loose Ends
If loose materials like gravel or brick dust are chosen for the paving surface, then the path will need to be edged with a strong, stiff edging material. Gravel, small stones with fines, crushed brick, or cypress mulch make nice loose paving. Buried rocks can be used, although it is a bit of a stretch to believe that they would grow on their sides naturally at the edge of a path. Staked plastic edging is not strong enough to hold gravel unless it is at least one-eighth of an inch thick. Aluminum or steel edging secured below grade with long stakes is ideal for loose paving. It should extend no more than one-quarter of an inch above grade to be unobtrusive and to avoid a tripping hazard. Logs can be used to edge loose paving, too. Railroad ties are not as well suited to woodland paths as they are to woodland parking lots. Their scale is too large for a foot path. Choose edging that blends into the natural surroundings.
Accessibility for Those with Disabilities
If your path is intended for wheelchair use, then loose materials must be angular or connective and compacted mechanically to form a smooth surface. Stepping stones must be exceptionally flat, closely spaced, and uniform in surface, so wheels can navigate the path. The width of the path must be at least three and one-half feet wide. Changes in grade must be kept to a maximum of thirty feet long and a maximum of five percent grade. Edges of paving must be at least one-half inch higher than the pavement surface. Handrails must be provided on ramps. ADA regulations are ambiguous about outdoor nature paths, but if you have ever experienced one fall, you will understand why I say all these guidelines should be met. People with walkers, wheelchairs, or canes must not be asked to walk on an obstacle course. Public nature trails can be equipped for special users. Wheelchairs in loose material like sand can be difficult to move, even a few feet.
Weeds are a constant maintenance problem for natural paths. Fallen trees are an issue, too. Trying to negotiate and avoid poison ivy and climb over or under large limbs is no fun. Invasive weeds need to be removed near paths before they go to seed, if possible. Chemical control is efficient if timed strategically. A natural path will certainly require regular maintenance, even with the best, self-sufficient design.
Landscape fabric can be used to line the bottom of a paved pathway. It prevents loose material from mixing with the soil particles in the subsurface. It doesn’t prevent weeds, because weeds can grow just as easily on top of the fabric as below it. All they need is one small bit of collected dirt on the fabric surface to establish roots that penetrate through the fabric from the top.
Fallen leaves can be blown away fairly cleanly with a gentle leaf blower. It's better to remove leaf litter than to allow the leaves to decompose into the loose paving material. A well-packed, interlocking path material holds up well to a leaf blower.
If prized native ground covers are tenacious enough to venture onto the path, allow it. They soften the strong line of the path. Foot traffic will keep the path clear of well-behaved native plants.
The materials you choose to import into your natural setting need to belong to the setting. There are several looks that suit native flora. Coarse, rugged logs and field stone can last for decades and look good. The old conservation corps construction projects in many state parks are a good example of the proper outdoor scale and use of materials. Natural step risers made of logs with loose gravel treads fit comfortably into a natural landscape. Look around when you visit a site to see if found materials are available for construction.
Rocks lend age and natural elegance to a path. Perfect, evenly spaced concrete pavers look as out of place in the woods as a yellow brick road. Randomly placed natural flagstone looks much better. Sculpt rocks to provide interest and enduring strength in a way that looks as if it happened naturally. Stones break with fluctuations in temperature, with crumbling gravel at the breaks. Stepping stone placement can mimic the broken stone look. Spaces between the stones can be filled flush with the stones to give a weathered, naturally-segmented look, or flat-growing ground covers can be tucked between the stone spaces.
The clean, simple lines of a modern boardwalk can fit a natural site if carefully designed. Simple lines and functional minimalism impose the least amount of hardscape intrusion into a difficult-to-traverse environment. This is good style that goes with a wetland situation, or where the pavement must be elevated to allow unobstructed water flow and prevent soggy feet for visitors. A boardwalk is a bridge, and the simplicity of the lines must be matched with the strength of the structure.
There are ways the style of a path can be more imaginative, without ruining the organic, natural site. Consider training and growing living elements into structures. Arbors can be formed from pleached trees. Structural supports can double as climbing trellises for vines. If the result is naturally organic, clean, and simple, then you have succeeded in added suitable style without damaging the woodland experience.
Your finished path should look as if it has been there either since the beginning of time...or at least since the C.C.C. An unassuming path protects plants and invites people into the heart of the natural, delicate environment without damaging traffic. With a well-designed, natural path, there should be no need for “keep on the paths” signs. People will want to use them, naturally.