In 1999, scientists dropped 45 tons of wollastonite over a 29-acre New Hampshire watershed

In 1999, scientists dropped 45 tons of wollastonite over a 29-acre New Hampshire watershed A large-scale effort to restore an American forest damaged by acid rain had an unexpected environmental effect when added nutrients caused a huge increase in nitrogen flowing into nearby streams. In October and November 1999, researchers spread about 45 short tons (40 metric tonnes) of a calcium-rich mineral over a 29-acre (11.8-hectare) catchment in New Hampshire. The treatment was meant to replace important soil nutrients that had been washed away by decades of industrial pollution. It worked at first, improving tree growth and leaf health over the next decade. But long-term monitoring later revealed a surprising change: by 2013, the treated valley was sending 30 times more inorganic nitrogen into its streams than nearby untreated forest catchments. The findings, published in the journal Proceedings of the National Academy of Sciences (PNAS), challenged long-standing ideas about how forest ecosystems handle nutrients. Scientists had expected a healthier, faster-growing forest to take in and store more nitrogen instead of allowing it to escape into nearby waterways.An experimental interventi...