From page 28 of the Environmental Assessment:
(
http://a123.g.akamai.net/7/123/11558/abc123/forestservic.download.akamai.com/11558/www/nepa/65572_FSPLT2_289179.pdf)
Under Alternative 3 the trail would be designated as open for mechanized/mountain bike use. Mountain bike use on the trail would have environmental effects.
Mountain bikes affect trail tread. In situations where trails climb or descend over forest soils such as are found along the proposed trail alignment (any trail alignment in this area located off of gravel surface roads), through repeated digging of mountain bike tire tread, trails are entrenched over time. The tread loosens soils, and subsequent rains wash it, creating down-cutting. Also, where the trail created by hiker and horse use is more likely to have relatively flat walking surface, the “cross section profile” of the tread of a trail used by mountain bike traffic is often rounded, or open horseshoe shaped. The consequence of this to the hiker and horse is that with each step, the foot is placed on an inward slope, turning the ankle and knee, and even hip, in an unnatural fashion. Long hikes on this kind of trail can result in unusual soreness in hikers or horses, and simply be uncomfortable. This can affect user experience.
Another effect observed in mountain bike trails in certain circumstances of slope and soils is the creation of a washboard or hummocking effect. Going uphill, each power stroke of the rider places uneven force on the soils, and over time can result in a hummocking effect, not unlike washboarding of roads but with much longer distances between dips. The gentle slopes of the new proposed location would be susceptible to this effect over time. The result for the hiker or horseback rider is that they find themselves walking up and down these dips to stay in the trail.
The social effects of mountain bike use on the trail include encounters by hikers and horseback riders with mountain biking parties. Mountain bikers travel much faster than hikers and or horses, and often “appear” quickly, causing hikers and horses to have to quickly yield. In downhill (from bikers perspective) situations this can even lead to safety issues. A biker coming around a corner at high speed can come upon a hiker before either party is aware of the other.
In general terms, bicycle use on the CDNST is not consistent with the overall objectives for the CDNST.
(um.. bullshit)
Later in the doc: (pg 89)
The mode of travel on a trail does have the potential to effect erosion potential. While there are those that would suggest some forms of travel such as mountain bikes have the ability to disturb and detach surface soils more readily than other non-motorized travel, there are no known studies that specifically address the erosion rates of horseback use compared to mountain bike use. Field observations by Forest Service personnel on the GMUG indicate that more critical than the mode of travel is the frequency and number of users on a trail. Trails experiencing high volumes of traffic from any form of non-motorized travel can experience down-cutting of the trail and increased erosion over those trail segments with less use. Development of the proposed trail using proper and recommended design elements that appropriately address grade and drainage would be expected to be able to adequately handle all modes of non-motorized trail without adverse impacts to the running surface of the trial or with increased erosion.
I think this is the heart of the matter: (pg 16)
Much of the existing trail is open for motorized (existing multiple purpose forest roads), and mechanized (mountain bike) use. It does provide a through route for mountain bike use. The experience had by the mountain biker is one of transitioning from one type of route to another across this segment of the CDNST. Biking forest roads which are being used by full sized motorized vehicles, and including commercial hauling of timber and other products at times, results in a reduced experience by the biker. It also presents some issues in terms of safety of users. Dusty roads with much traffic are unpleasant and can be dangerous to the mountain biker.
Now, tell the USFS how you feel.
