With our literature review, we found that once vegetation diminishes soil erosion accelerates and is augmented by the various geomorphological and environmental factors (Wilson and Seney, 1994). Therefore, it is desirable to maintain a good cover of vegetation on the site.

Trampling on vegetation is well documented and studies show that understory vegetation with high density have the most resistance to trampling and inhibit trail widening (Leung and Marion, 1996). This suggests that understorey vegetation is most useful in preventing widening of trails. The lateral spread of a trail is minimized by dense trailside vegetation whereas open meadows generate multiple treads (Leung and Marion, 1996). Grass could be likened to an open meadow, suggesting that the presence of grass is somewhat of an invitation for people to continue widening trails. For these reasons, we feel that the best type of vegetation to select when rehabilitating the site would be something which grows densely and is taller than grass (although, for safety reasons, we feel it is important to maintain visibility and therefore avoid the use of many shrubs).

Although we were unable to find sources on the psychology of trail use, which would have helped us to effectively design a site that would deter people from walking off trails, we did conclude that an effective vegetative detterent could probably be made from vegetation which is prickly and unpleasant to walk through.

We also felt that one of the major purposes of vegetation on the berm would be that of slope stabilization, to prevent gradual erosion of soil from runoff.

In our research, the plant which most effectively met the above needs was Carolina (or Pasture) Rose (Rosa carolina).

With consideration of all of our research, we have created a suggested berm design which would increase the sustainablity of the berm and pathway system. This design is based on the results of our traffic count and a review of possible vegetation types and trail materials.

To enhance sustainability, we have tried to incoporate a wide range of considerations into our berm design, including:

  • Convenience: Our traffic count found that, aside from the paved path, one of the trails was very heavily used. We have decided to make this into a permanent path, to enhance the convienience of the pathway system. We feel that if walkways are placed in convenient locations with more natural angles, instead of straight lines, people would have no need to deter from them.
  • Economics: Of the materials we investigated, we found flagstone to be relatively inexpensive. It is permanent and requires less maintenance than gravel and woodchips. Although a boardwalk is considered a good choice, it would be expensive and hard to maintain.
  • Aesthetics: Flagstone is an attractive alternative to pavement. Also, the suggested vegetation was chosen for its visual attractiveness.
  • Safety: In our design we have avoided the use of a large number of shrubs, since these reduce visibility. Where shrubby trees (ie: red cedar) are used, they are placed singly and widely spaced.
  • Accesibility: The new pathway should be designed to be wheelchair accesible.
  • Ecosystem health: The new design enhances vegetation health by reducing soil erosion and localizing soil compaction to the permaent paths.
  • Utility: The new design incorporates plants which are attractive and useful to wildlife. (Some are useful to people as well!)

Figure 7.1 is a diagram of our suggested berm design. Please note: We have not yet decided upon the placement of the new permanent path. We may change the placement based on further consideration of the root zones of nearby trees. Table 7.1 shows existing and suggested vegetation.

Figure 7.1: Recommended Berm Design

Table 7.1: Existing and Suggested Vegetation

        EXISTING VEGETATION

    SUGGESTED VEGETATION

1. Norway Maple
2. Scotch Pine
3. Silver Maple
4. Scotch Pine
5. Scotch Pine
6. Scotch Pine
7. Scotch Pine
8. Silver Maple
9. Norway Maple
10. Norway Maple
11. Norway Maple
12. Norway Maple
13. Norway Spruce
14. Norway Spruce
15. Norway Maple
16. Norway Maple
17. Norway Maple
18. Norway Spruce
19. Norway Spruce
20. Silver Maple
21. Norway Maple
22. Norway Maple
23. Norway Maple
24. Norway Maple
25. Norway Maple
26. Norway Maple
27. Norway Maple
28. Norway Maple
29. Norway Maple
30. Scotch Pine
31. Scotch Pine
32. Scotch Pine
33. White Ash
A. Eastern Red Cedar
B. Carolina Rose
C. Wild Strawberry
D. Blue Phlox