Impacts on vegetation by mountain bikers and hikers
Mountain biking and singletrack trails live within a management framework that is increasingly charged with environmental conservation mandates. Further, ‘romantic-conservation’ and other moralizing and value judgement based decisions about mountain biking are still taking place today despite the continued push for data driven decision making at government levels. This study, conducted in Boyne Valley Provincial Park, highlights the similar impacts of both hikers and mountain bikers on understory vegetation from off trail usage. Additionally it validates operational and advocacy perspectives useful to landmanagers and trail steward organizations.
This study compared the effects of experimentally applied mountain biking and hiking on the understory vegetation and soil of a deciduous forest. Five different intensities of biking and hiking (i.e., 0, 25, 75, 200 and 500 passes) were applied to 4-m-long 1-m-wide lanes in Boyne Valley Provincial Park, Ontario, Canada.
Discussion
In the center zone, both vegetation loss and species loss occurred rapidly with biking or hiking activity. After only 25 passes nearly every plant stem present in the center zone was damaged.
Very little traffic is required to make an observable impact on vegetation following rogue or off trail usage by hikers or mountain bikers.
… the loss of organic horizons does not occur as rapidly or does not become as severe at low trampling intensities as does vegetation loss.
Soil loss takes place at a much slower rate than does vegetation, making vegetation loss from user impacts a primary indicator of off-trail usage.
The amount of soil still exposed after one year in treated lanes did not differ significantly from control lanes. The absence of a detectable treatment effect was likely due to the addition of deciduous tree leaves to the forest floor in the autumn following treatment application. Over-winter reduction in exposed soil has been attributed to leaf fall by a number of investigators
The detritus buildup following the study helped to close the trail, particularly the over-winter process described in the study.
The magnitude of biking and hiking effects on vegetation and soil declined sharply with distance from the center of the treatment lane. After a maximum of 500 passes, visible impact was concentrated within a narrow zone, no greater than 30 cm from the lane centerline … [beyond 30cm] almost no foot or bike tire contacted the ground and no changes in parameters could be detected after treatments were applied.
60cm overall width used as a reference point for user width of both hikers and mountain bikers, with little to no impact of vegetation beyond that.
In Practice
Most users – hikers and mountain bikers alike – will tend to stay on the trail. Be wary of push-pull factors that direct people off trail and account for them with design, messaging, or construction tools.
For Operations
1. Monitor under-story vegetation as an early indicator signal of off trail usage.
2. Quickly close newly formed informal trails as obvious trails form after very few passes.
3. Plan trail rehabilitation and restoration around the wintertime for problematic areas, allowing for leaf litter and other organics to cover the soil and contribute to regeneration.
For Advocacy
1. Mountain bikes and hikers have no significant difference in vegetation and soil disturbance in this instance.
2. Very little usage is required to create a new informal trail, leaving a outsized impact on the environment generated by a minority of users.
THURSTON, E., READER, R. Impacts of Experimentally Applied Mountain Biking and Hiking on Vegetation and Soil of a Deciduous Forest. Environmental Management 27, 397–409 (2001). https://doi.org/10.1007/s002670010157″