The world's poorest continent could offer clues to how America's farmers might cope with a hotter, drier climate, leading agriculture experts say. In the African Sahel -- the belt of semiarid savanna running from the Atlantic Ocean to the Red Sea -- farmers have successfully fought back an expanding Sahara and turned once dry, uncultivated scrub into highly productive farmland. The key to their success has been allowing trees to grow, where they once cut them down, and adopting agricultural techniques that took full advantage of scarce water resources. Now experts say it is time for American farmers to recognize the benefits that trees can bring to even the most arid plots of land. Go to story #1