Soil Displacement and Erosion on Bike-Optimized Trails in a Western Oregon Forest
published April 03, 2016
The emergence of electric bicycles, commonly known as e-bikes, is a rapidly growing component of the bicycle market in the US (MacArthur and Kobel, 2014). As a transportation option, they represent an opportunity to reduce vehicle use and emissions, as well as the physical barriers to cycling. For use on trails, they present similar opportunities to reduce barriers to cycling but, as a new use, present new challenges for trail management.
While already popular in Europe, the use of eMTBs is on the rise in North America, and their increased presence is sparking controversy within the trail user community. Electric mountain bikes are generally defined as motorized vehicles for the purposes of trail use on federal lands, with states and municipalities expected to make their own decisions.
All trail users affect the trail surface and surrounding environment, especially when trails are poorly constructed. Those impacts range from vegetation loss to soil erosion, and related water quality problems. However, there is no evidence that traditional mountain bicycling causes greater environmental impact than other recreational trail uses. In fact, current research suggests that mountain bicycling impacts are similar to hiking, and less damaging than equestrian and motorized users.
There have been no studies of the environmental impacts of eMTBs specifically, but there exist numerous studies on the impacts of both mountain bicycles and off-road motorcycles, which provide a basis for developing research protocols. One could speculate that the impacts of eMTBs on trails would fall somewhere between the two modes, but this is a rather wide span, particularly regarding soil displacement under certain trail conditions, e.g., turn exits, steep grades, and/or non-cohesive soils.
The lack of existing data may contribute to poor trail management decisions that may either unnecessarily ban eMTBs from trails or allow them where their impacts will be disproportionate to their use. An understanding of how eMTBs affect the environment and trail management is needed so that land managers and the communities that support them can make informed access decisions.
The purpose of this study was not to decide whether eMTBs should be regulated as bicycles or motorcycles, or whether they are appropriate for shared-use on non-motorized trails. These decisions are for land managers to make in consultation with their recreation community. This report provides an understanding of some of physical impacts to trails associated with this use, and how these might differ from those associated with traditional mountain bicycles.