(AP) — In this photo taken Thursday, Dec. 13, 2012 is a vineyard that was grafted with Cabernet Sauvignon earlier this year at Trefethen Family Vineyards in Napa, Calif.
Napa Valley, one of California's premier wine growing regions, has an uncommon problem these days: Not enough new grape root stock to go around. Commercial nurseries were caught short by a trifecta of developments: aging vines planted after a deadly phylloxera outbreak of the 80s, the demand created by an improving economy and move toward grape plantings that allow some mechanization. (AP Photo/Eric Risberg)
