Mature trees offer hope in world of rising emissions

“I think it is a hopeful and positive story,” said Professor Rob MacKenzie, director of Birmingham Institute of Forest Research and one of the co-authors of the study.

“This is evidence in favour of careful management of established forests. The old forest is doing a huge amount of work for us. What we definitely should not be doing is cutting it down,” he said.

The results of this latest study come from the University of Birmingham’s giant Free-Air Carbon Dioxide Enrichment (FACE) experiment, which Prof MacKenzie has headed since its inception in 2016.

FACE is located at a 52-acre forest in Staffordshire and its aim is to understand the impact of our changing climate on woodlands in real-time.

Within the site is a group of 180-year-old English oak trees, and amongst their towering 40m canopies the academics have plumbed in a network of pipes.

Every day these pipes send out a stream of carbon dioxide (CO2) – the greenhouse gas – recreating the conditions the world might see if no action is taken to reduce emissions.

After seven years of monitoring the team of international researchers working at FACE ha, externals revealed, external that the oak trees have increased their productivity under these elevated levels of CO2.

The trees produced nearly 10% more wood, locking in the carbon dioxide for years to come and preventing it from warming the atmosphere.

When trees take in carbon dioxide they can use it in different ways – to produce new leaves, roots or woody biomass.

New leaves and roots are seen as short term stores of carbon dioxide as they can shed or die relatively frequently re-releasing the gas back into the atmosphere. But the researchers found most of the CO2 was converted to forms that enable it to be stored for many decades.