HOUSTON COUNTY, Ga. China is hungry for American pecans and other American tree nuts, such as almonds and walnuts. The export market for U.S. farmers has grown from $77 million in 2000 to over a billion dollars in 2012, according to the U.S. Department of Agriculture. “Some of them wind up in a couple of candy places here in Georgia, but I would say 60 percent of ours are shipped overseas,” says Thomas L. Mason, a pecan farmer in Houston County.