Study: Rainforest captures carbon faster after being logged, cleared for agriculture

“Far-reaching implications for forest restoration projects to mitigate global warming’… Gentlemen…. start your chainsaws….

The media release is below.

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Tropical forests ‘fix’ themselves

New results from the Smithsonian’s Panama Canal Watershed experiment

ropical forests speed their own recovery, capturing nitrogen and carbon faster after being logged or cleared for agriculture. Researchers working at the Smithsonian Tropical Research Institute in Panama think the discovery that trees “turn up” their ability to capture or “fix” nitrogen from the air and release it into the soil as the forest makes a comeback has far-reaching implications for forest restoration projects to mitigate global warming.

“This is the first solid case showing how nitrogen fixation by tropical trees directly affects the rate of carbon recovery after agricultural fields are abandoned,” said Jefferson Hall, STRI staff scientist. “Trees turn nitrogen fixation on and off according to the need for nitrogen in the system.”

Hall directs the Agua Salud Project, an experiment spanning more than a square mile of the Panama Canal watershed. Researchers compare land-use options, measuring carbon storage, runoff and biodiversity to find out how mature tropical forest, native trees in forest restoration plots and abandoned pastureland compare. The project hosted the collaboration between scientists at Princeton University, Wageningen University, the University of Copenhagen, Yale University and STRI to explore the relationship between nitrogen fixation and carbon storage.

They compared tree growth rate and nitrogen levels growing on pastureland abandoned two, 12, 30 and 80 years ago with trees growing in mature forests. Tree species that “fixed” nitrogen from the atmosphere put on carbon weight up to nine times faster than their non-fixing neighbors during early stages of forest recovery. Nitrogen-fixers provided enough nitrogen fertilizer in the soil to facilitate storage of 50,000 kilograms of carbon per hectare during the first 12 years of growth.

“Diversity really matters,” said the study’s first author, Sarah Batterman, who worked collaboratively on the project with Lars Hedin at Princeton University. “Each tree species fixes nitrogen and carbon differently so species important at 12 years drop out or become less common at 30 years. You can really see how different players contribute to the development of a mature tropical forest and the ecosystem services it provides.”

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7 thoughts on “Study: Rainforest captures carbon faster after being logged, cleared for agriculture”

  1. Gee, funny that, plants using more nitrogen and carbon dioxide when they are growing the fastest. How’d have thunk it!

  2. That is something I have wondered about. In Europe now, they use a lot of wood, and wood pulp to generate electricity because it is “renewable” but eco freaks scorn anyway, because they say it takes 100 years to get that CO2 out through the CO2 cycle. But tree farms typically grow trees to harvest in 15 to 20 years. So if they are getting the wood from tree farms (which they should be) you would think the CO2 would be away in 20 years.

    Anyway, yes, if you use the wood for a house, and the land is free to regrow, it will suck up CO2 like anything until the primary canopy comes back.

  3. Plants are no different than children–when they are young they eat more. What a revelation! This is a reason for logging rather than supporting old growth forests, both if you believe in multiple use management and climate change due to carbon dioxide.

  4. A mature ‘old growth’ forest is a full carbon reservoir. It cannot capture any more carbon. All the carbon it needs it can get from decay of it’s own biomass in the understory. Fungi, insects, and small animals are very good at converting biomass into CO2.

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