A new international study published in the journal Nature found that about 15 percent of forested land in the Northern Hemisphere is unmanaged primary forests with large amounts of old growth. These stands may account for 10 percent of the global net uptake of carbon dioxide.

The report's author, Sebastiaan Luyssaert of the University of Antwerp, Belgium, and his colleagues, analyzed years of FLUXNET data, a global network of observatory towers that measure the exchanges between forest ecosystems and the atmosphere.

New findings dispute claims that forests give off as much CO2 as they take up. Old growth forests both under tenure and not yet under tenure was not included in the Kyoto Protocol. These forests should be taken into account in the global carbon balance assessments, and in negotiations for the post 2012 Global Climate Agreement.