On the horizon: news from the frontiers of science

Giant birdlike dinosaur weighed 1.5 tons; research rebukes Bush approach on wildfire zones; fertile forests may soak up more greenhouse-gas emissions.

from the June 14, 2007 edition

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This time around, a team led by OSU's Jonathan Thompson (who was not an author of the 2006 study) looked at parts of the 2002 fire zone that burned twice – once in 1987 and again in 2002.

Overall, the scientists found that the 2002 fire was from 16 to 61 percent more severe in the areas that had been logged and replanted in 1987 than in comparable areas that grew back naturally. The team says it's not sure what accounts for the difference. It could be that, at least for the first 10 to 20 years after a fire, "managed" areas contain lots of logging debris, as well as tree seedlings or saplings. This leaves significant amounts of fuel closer to the forest floor than would otherwise be the case. The results appear in this week's issue of the Proceedings of the American Academy of Sciences.

Fertile forests absorb more CO2

Much has been made of temperate and boreal forests' ability to trap carbon dioxide emitted by cars, factories, and power plants that burn oil, gas, and coal. But researchers have found that, all other things being equal, those "sinks" won't be of much long-term help if other factors, like rainfall and available nutrients, don't keep pace.

Now, a team of scientists in Europe has concluded that forests in fact are getting additional nutrients – from nitrogen released into the air from burning fossil fuels, as well as from the use of fertilizers on farms. Indeed, the team calculates that human-provided nitrogen – roughly 15 pounds per acre – plays a significant role in stimulating carbon sequestration in boreal and temperate forests.

Others caution that much remains to be learned about the relationship between additional amounts of nitrogen added and the additional amount of carbon that trees soak up. Moreover, the results appear to overestimate the benefit that others had derived. It bears on the question of whether forests should be fertilized to soak up more CO2. The results appear in today's issue of the journal Nature.

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