Stock Photo: Ann Arbor, Michigan - Volunteers rebuild a section of a hiking trail in Black Pond Woods The volunteers were recruited through Recreational Equipment Inc REI in cooperation with Ann Arbor´s Natural Area Preservation It was one of many volunteer project. Ann Arbor, Michigan - Volunteers rebuild a section of a hiking trail in Black Pond Woods The volunteers were recruited through Recreational Equipment Inc REI in cooperation with Ann Arbor´s Natural Area Preservation It was one of many volun