AMAZON - More than half of all tree species in the Amazon face extinction, warn international scientists. According to new data, up to 57% of all Amazonian trees may already fit the criteria of being globally threatened. If confirmed, the estimates would raise the number of threatened plant species on Earth by almost a quarter. Forest cover in the Amazon has been shrinking for decades, but little is known about the impact on individual plant species. The trees at risk include iconic species like the Brazil nut tree, food crops such as cacao, the source of chocolate, as well as rare trees that are almost unknown to science.–BBC