Nitrous oxide - no laughing matter for forests

This is getting serious. Climate change could cause forests in Europe to spew out more and more nitrous oxide, aka laughing gas, a potent contributor to global warming.
As a greenhouse gas, N2O is 296 times as powerful as carbon dioxide and accounts for 6 per cent of the greenhouse effect. To better understand the N2O output from forests, Klaus Butterbach-Bahl of the Karlsruhe Research Centre in Germany and team members Per Ambus and Sophie Zechmeister-Boltenstern studied N2O emissions from 11 European forests (Biogeosciences, vol 3, p 135).
They found that nitrifying soil bacteria thrive on high nitrogen levels, producing mainly nitrates, which are turned into N2O by denitrifying bacteria. As human activity adds more nitrogen to the biosphere, the production of N2O by the bacteria looks set to grow.
The team also found that deciduous forests made more N2O than coniferous ones - a concern, as Europe is promoting deciduous forests to increase biodiversity.
Worryingly, denitrifying bacteria worked best in warm and moist soil. "If it is going to be warmer and wetter, as predicted for many parts of Europe, then N2O emissions will go up," says Zechmeister-Boltenstern.
From issue 2569 of New Scientist magazine, 20 September 2006, page 16