In the centuries-old cork forests of southern Portugal, locals who for generations have harvested the bark that bungs billions of bottles around the world don\'t think much of the rival plastic stoppers and metal screwcaps threatening their livelihoods. \"Cork is a safer bet,\" says Joao Simoes, a 64-year-old, as he peels the bark off a cork oak — a job he\'s been doing for the past 40 years. \"It seals [bottles] better.\" Some of the world\'s leading winemakers disagree. Since the turn of the century they have used more and more alternative stoppers in an unprecedented threat for the economy of Portugal, the world\'s largest cork producer and one of western Europe\'s poorest countries. Makeover Article continues below The competition compelled Portuguese cork companies, accustomed to a long-standing near-monopoly, to embark on a do-or-die makeover. Now, producers say, their modernisation and diversification programme is paying off. They say they have checked the steep drop in the market share for cork stoppers, holding it at around 70 per cent for the past two years. And last year cork exports improved for the first time in a decade with growth of more than 8 per cent, according to National Statistics Institute. \"For the first time in 250 years, the cork industry was actually challenged,\" says Antonio Amorim, chairman and CEO of Amorim, Portugal\'s oldest and largest cork company. \"We would like to ... think that the worst times for the cork industry are behind us.\"