30-Year Project Examines Nitrogen Fertilization in a Spruce-Fir Forest
In the 1960s, forests across New England were declining. The decline affected red spruce and balsam fir forests, especially those at high elevations. “Researchers agreed that acidic deposition was the primary cause of the decline,” says Eastern Threat Center research ecologist Steve McNulty. “However, most of the decline was blamed on sulfur not nitrogen deposition, and the mechanisms for the mortality were unclear.” After a regional field survey across high elevation spruce-fir forests, McNulty and his colleagues decided to conduct a study on Mount Ascutney, in Vermont. They hypothesized that chronic low doses of nitrogen could cause the forest decline. In 1988, the scientists established research plots and treated some of them with a nitrogen-rich fertilizer. Some plots received 35 pounds of nitrogen per acre each year, and others received 70 pounds of nitrogen per acre each year (rates that were equal to nitrogen deposition occurring in parts of Europe at the time). After a few years, the local nitrogen cycle was affected. Results were recently published in the journal Science of the Total Environment. Read more in CompassLive...
