the entire U.S. population of Fraser firs suffered a 67% mortality rate since, although Mount Rogers was not affected as severely as other locations. Some researchers have proposed that air pollution in the form of nitrogen and sulfur compounds originating from power plants has been a source of stress to the Fraser firs, resulting in an increased susceptibility to the balsam woolly adelgid, but this relationship has not been confirmed. Wild ponies Mount Rogers and the surrounding area is home to around 100 wild ponies, one of the few places in the United States where they live in the wild. According to Smithsonian Magazine, the ponies have lived in the area since the 1940s. In 1974, the Wilburn Ridge Pony Association was formed to help manage the herd and maintain the grassy area where they graze. See also High Knob Mount Rogers Cluster Mount Rogers National Recreation Area Reddish Knob Whitetop Mountain References Highest points of U.S. states Mountains of Virginia Mountains on the Appalachian Trail George Washington and Jefferson National Forests Blue Ridge Mountains Landforms of Grayson County, Virginia Landforms of Smyth County, Virginia Volcanism of Virginia Proterozoic volcanism Rift volcanism North American 1000 m summits Southwest Virginia