By Mark Kinver, Environment reporter, BBC News

Dr Nabuurs explained that saturation referred to the point where the natural carbon sinks were unable to keep pace and absorb the additional atmospheric carbon being released by human activities.
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The researcher’s conclusions appear to contradict the State of Europe’s Forests report in 2011 that showed forest cover in Europe had continued to increase. The report said trees covered almost half of Europe’s land area and absorbed about 10% of Europe’s annual greenhouse gas emissions.

But Dr Nabuurs said that the rate of afforestation was slowing, adding that a sizeable proportion of forests were mature stands of trees, which were mainly planted in the early part of the 20th Century or in the post-World War II periodForests absorb about 10% of the EU’s annual greenhouse gas emissions

« These forests have now reached 70-80 years old and are starting a phase in the life of a tree where the growth rate starts to come down, » he explained.