Skip to comments.Researchers discover trees in Amazon much older than assumed (Not as helpful with global warming)
Posted on 12/13/2005 10:56:43 AM PST by DaveLoneRanger
Older trees may have less capacity for taking in carbon dioxide
Irvine, Calif., December 8, 2005 Trees in the Amazon tropical forests are old. Really old, in fact, which comes as a surprise to a team of American and Brazilian researchers studying tree growth in the worlds largest tropical region.
Using radiocarbon dating methods, the team, which includes UC Irvines Susan Trumbore, found that up to half of all trees greater than 10 centimeters in diameter are more than 300 years old. Some of the trees, Trumbore said, are as much as 750 to 1,000 years old. Study results appear in the online early edition of the Proceedings of the National Academy of Sciences.
Little was known about the age of tropical trees, because they do not have easily identified annual growth rings, added Trumbore, a professor of Earth system science. No one had thought these tropical trees could be so old, or that they grow so slowly.
And for Trumbore, who studies how forests and the atmosphere exchange carbon, these discoveries can have implications for the role the Amazon plays in determining global carbon dioxide levels. Carbon dioxide is a greenhouse gas implicated in accelerated global warming and the focus of international efforts to curb its atmospheric levels.
Because their trees are old and slow-growing, the Amazon forests, which contain about a third of all carbon found in land vegetation, have less capacity to absorb atmospheric carbon than previous studies have predicted. Although some of the largest trees also grow the fastest and can take up carbon quickly, the vast majority of the Amazon trees grow slowly.
In the Central Amazon, where we found the slowest growing trees, the rates of carbon uptake are roughly half what is predicted by current global carbon cycle models, Trumbore said. As a result, those models which are used by scientists to understand how carbon flows through the Earth system may be overestimating the forests capacity to remove carbon dioxide from the atmosphere.
As part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA), the researchers revealed an interesting portrait of tree life beneath the limbs of the large trees that dominate tropical forests. They found that most Amazon basin trees are so old because they grow very slowly on nutrient-poor soils in dark shade under the canopy of large trees. The growth rates they measured for Central Amazon trees are among the slowest in any forest on Earth. These results, Trumbore points out, are contrary to the widely held view that tropical forests are highly dynamic.
In addition, the impact of logging activity in the Amazon region may be longer-lasting than we think, Trumbore added, because it may take centuries for these forests to grow back to their full size.
Some of the older trees found in the study included economically valuable species. For example, three Brazil nut trees measured in the study ranged in age from 680 to 1,000 years.
Supported by NASA, the LBA is a Brazilian-led international scientific program with the goal of studying how the Amazon forest affects global climate and carbon dioxide. The work was a cooperative effort among researchers at the University of Sao Paulo, University of Acre and the Institute for Amazonian Research in Brazil, and UCI and Tulane University in the U.S. Radiocarbon measurements were made at the W.M. Keck Carbon Cycle Accelerator Mass Spectrometry Facility at UCI.
Also, isn't this like the first time that scientists have guessed that something is younger and then proved themselves wrong? Usually, it's the other way around and they're saying something is billions of years older.
"Researchers discover trees in Amazon..."
Trees... in the Amazon... wow!
Did they find any rivers?
Older than McCain?
Apparently they were planted by Helen Thomas.
So...we need to knock down old-growth forests to save the earth?
Grasslands are much more efficient than forests when it comes to absorbing CO2. Let's save the world by getting rid of the rain forests and replacing them with grasslands.
"Save the planet...replace the amazon rainforests with golf courses!"
Getting Gay with Kids was right after all:
There's a place called the rainforest; it truly sucks a**.
Let's knock it all down and get rid of it fast.
You say, "Save the rainforest," but what do you know?
You've never been to the rainforest before.
Getting Gay With Kids is here!
To tell you things you might not like to hear.
You only fight these causes 'cause caring sells.
All you activists can go f*** yourselves!
Someday if we work hard, boys and girls,
There'll be no more rainforests left in the entire world!
Getting Gay With Kids is here!
To spread the word and bring you cheer. Yeah!
Getting Gay With Kids is here!
Let's knock down the rainforest! What do you say?!
It's totally gay! It's totally gay!"
And algae more efficient still. If I remember my science training of many years ago, oceanic algae convert 65% of all carbon dioxide...
How can a forest be carbon sink? When a tree dies, it rots and releases the carbon dioxide. The Amazon tropical forests are about 50,000 years old. The only way the forest could be a net producer of oxygen and absorber of carbon dioxide would be if there were 50,000 years worth of trees buried under it all.
Death with Dignity...
Wait, people GET more lines as THEY get older, maybe the trees are actually YOUNGER than we think.
Huh? According to her own figures, the sequestration of carbon may be higher than currently estimated.Tree Root Study May Unbalance Greenhouse-Gas AccountingUntil recently researchers hypothesized that roots less than two millimeters in diameter, which are responsible for most below-ground nutrient cycling, live for about a year. Roser Matamala of Argonne National Laboratory and her colleagues have now completed a five-year-long experiment that suggests otherwise. The team exposed two types of trees -- sweetgums and loblolly pines -- to CO2 labeled with carbon 13 and then tracked the heavy carbon as it appeared in the soil. According to the report, the roots lasted between 1.2 and nine years, with the pine tree roots lasting longer on average than those of the sweetgum. "These long turnover times suggest that root production and turnover in forests have been overestimated," the authors write, "and that sequestration of anthropogenic atmospheric carbon in forest soils may be lower than currently estimated."
by Sarah Graham
November 21, 2003
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