The USDA Forest Service has requested that all vehicles that would run on the Fordyce Jeep Trail be washed immediately prior to the event. This is a preventative measure to help prevent the introduction and spread of noxious weeds such as yellow star thistle. Vehicles can spread weeds from one site to another by carrying plant parts and seeds.
When a vehicle is driven through a weed-infested area, weed seeds may become lodged between the tire treads, in the coils of a winch, behind the license plate, or in cracks and crevices on the underside of the vehicle. Seeds may travel hundreds of miles before becoming dislodged in an area where the weeds were not previously found. The source of many weed infestations has been traced to roads, trails, railroads, and other travel ways.
To prevent the spread of weeds from vehicles participating in the Sierra Trek event, thoroughly wash the undercarriage and tire-tread of the vehicle to remove seeds and bits of vegetation. This material may have been picked up during the last run or from where the vehicle was last parked. Noxious weeds such as yellow star thistle are common in urban areas and along the highways leading to the Sierra Trek event.