And there was a more compelling reason to go. The Appalachians are the home of one of the world’s great hardwood forests-the expansive relic of the richest, most diversified sweep of woodland ever to grace the temperate world-and that forest is in trouble. If he global temperature rises by 4°C over the next fifty years, as is evidently possible, the whole of the Appalachian wilderness below New England could become savanna. Already trees are dying in frightening numbers. The elms and chestnuts are long gone, the stately hemlocks and flowery dogwoods are going, and the red spruces, Fraser firs, mountain ashes, and sugar maples may be about to follow. Clearly, if ever there was a time to experience this singular wilderness, it was now.

So I decided to do it. More rashly, I announced my intention-told friends and neighbors, confidently informed my publisher, made it common knowledge among those who knew me. Then I bought some books and talked to people who had done the trail in whole or in part and came gradually to realize that this was way beyond-way beyond-anything I had attempted before.

Nearly everyone I talked to had some gruesome story involving a guileless acquaintance who had gone off hiking the trail with high hopes and new boots and come stumbling back two days later with a bobcat attached to his head or dripping blood from an armless sleeve and whispering in a hoarse voice,“Bear!” before sinking into a troubled unconsciousness.

The woods were full of peril-rattlesnakes and water moccasins and nests of copperheads; bobcats, bears, coyotes, wolves, and wild boar; loony