Copy shortlink: The Department of Natural Resources has rejected the latest plea from a citizens group to formally review alleged environmental threats from a proposed 764-mile back-roads driving route that the agency intends to open across northern Minnesota for four-wheel drive owners. The petitioners are concerned that the so-called Border to Border Touring Route will unduly escalate traffic of high-impact vehicles on natural surface roads that snake through remote forest lands amid pristine waters and sensitive wetlands. The group —Citizens for Sustainable Off-Roading — foresees harmful sediment getting splattered into fragile trout streams; vehicles sparking forest fires; rare species suffering from environmental damage; vehicles spewing air and noise pollution; the spread of invasive species; and an intensified level of motorized intrusions upon bird-watchers, hunters, sightseers and other low-impact recreational users of the roads.