Not always the ring of truth

摘要

Tree rings are Mother Nature's history books. Researchers often look at chemicals stored in them when trying to reconstruct past environments. Like all history books, though, they can be unreliable. And in the case of one particular chemical of interest, mercury, Jose Antonio Rodriguez Martin of the National Institute for Agricultural and Food Research and Technology, in Madrid, and his colleagues have just shown how unreliable they are. Dr Rodriguez Martin was studying pines on La Palma, in the Canary Islands. He knew that Hoyo Negro, one of the island's volcanoes, had erupted violently in 1949, and believed that the clouds of ash and explosive ejections of rock from the eruption had destroyed all of the pines nearby. However, as he describes in Natur-wissenschaften, when he and his team examined the area, they were stunned to discover a revenant from this cataclysm just 50 metres from the crater.