I just learned that the Appalachian Trail is more than a half-mile shorter than it was just three years ago.According to the Appalachian Trail Conservancy, for the first time in nearly two decades, the trail this year was measured as shorter for the second consecutive year, when the ATC did the official measurement for the 2007 edition of the AT Data Book.The AT now stands at an official 2,174 miles, after a 0.6 of a mile reduction that resulted...