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.
Meet the really 'Big Bird'
Among birdlike dinosaurs, there's a new giant on the block. A team of Chinese paleontologists say they have discovered an oversized cousin to creatures like the velociraptor, of "Jurassic Park" infamy. The new dinosaur, dubbed Gigantoraptor erlianensis (see photo), would have stood just over 11 feet tall at the hip, stretched 26 feet from tail to beak, and tipped the scales at 1.5 tons.
The researchers uncovered Gigantoraptor's fossil remains in Inner Mongolia. The pieces include a lower jaw, rib segments, virtually complete fore and hind legs, and tail bones. The 70-million-year-old find is counted among "coelurosaurs," which evolved into modern birds. As coelurosaurs evolved, for the most part they became smaller as they became more birdlike. But Gigantoraptor bucked the trend. This "Baby Huey" fits squarely within a group of coelurosaurs that rarely weighed more than about 88 pounds. But it displays many birdlike features not found in its smaller relatives. In addition, the researchers say, their specimen displays important skeletal traits never before seen in any other dinosaur fossils. The results appear in today's issue of the journal Nature.
Best way to reduce fire intensity
If a wildfire burns through a patch of forest, don't salvage leftover logs, and don't intentionally replant trees if you want to reduce subsequent fire hazards there.That's the advice implied in a new study that looks at the aftermath of the 2002 Biscuit Fire in Oregon – one of the largest wildfires in modern US history. The findings appear to support an earlier Oregon State University study of the fire published last year. That study reached a similar conclusion and sparked a firestorm of controversy, as it bucked conventional wisdom about how to treat burned forests after a wildfire. The Bush administration has been a staunch supporter of salvage logging in the wake of wildfires as part of its Healthy Forests plan.
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.