The longest-lived trees are able to respond to their environment and adapt. Scientists at the University of Birmingham in the UK exposed a 180-year-old English oak forest to elevated levels of carbon dioxide for seven years.
In response, trees increased their wood production, sequestering greenhouse gases and helping to fight global warming.
Researchers hope the study, published in Nature Climate Change, will demonstrate the importance of protecting and maintaining mature forests to address climate change.
It is estimated that one football field of primary forest is lost every six seconds worldwide.
“I think that It is a hopeful and positive story“said Professor Rob MacKenzie, director of the Birmingham Forest Research Institute and one of the study’s co-authors.
“This is evidence in favour of careful management of existing forests. Old growth forests are doing a lot of work for us. “What we definitely shouldn’t do is cut them down,” he said.
The results of this latest study come from the University of Birmingham’s giant Open Air Carbon Dioxide Enrichment Experiment (FACE), which Professor MacKenzie has led since its inception in 2016.
FACE is located in a 21 hectare forest in the Staffordshire region and its objective is understand the impact of our changing climate on forests in real time.
Inside the site is a group of 180-year-old English oak trees, and between their imposing canopies, more than 40 metres high, the academics have connected a network of pipes.
Every day, these pipes send out carbon dioxide (CO2), the gas responsible for the greenhouse effectwhich recreates the conditions the world could see if no action is taken to reduce emissions.
After seven years of follow-up, the team of international researchers working on FACE revealed that Oaks have increased their productivity with these high levels of CO2.
The trees They produced almost 10% more wood, retaining carbon dioxide for years and preventing it from warming the atmosphere.
When trees absorb carbon dioxide, they can use it in different ways: to produce new leaves, roots or woody biomass.
Increased storage
New leaves and roots are considered short-term carbon dioxide stores, as they can shed or die relatively frequently, releasing the gas back into the atmosphere.
But researchers found that most of the CO2 became forms that allow them to be stored for many decades.
Previous experiments have shown that younger trees are able to increase their CO2 uptake rates, but It was believed that more mature forests do not have the same adaptability.
Professor MacKenzie told the BBC it was important for the team to understand how older trees behave as they make up the majority of the tree cover we have globally.
Although the results are positive, he warned: “This is by no means a panacea and a carte blanche not to pay the price for our fossil fuel emissions.”
“There is absolutely no way we can transform the world into enough forests to continue allowing us to burn fossil fuels as we are doing now,” he said.
The experiment has been extended until 2031 so that researchers can continue monitoring the oaks and see if this behavior continues.
Richard Norby, a research professor at the University of Tennessee and an author on the study, said: “It is essential that the FACE experiment continues for more years because we know that responses can change over time. A longer-term record will increase our confidence in the results.“.
They also hope to look at the impact of elevated CO2 levels on tree lifespans and impacts on other biodiversity such as insects.
While conducting this experiment, Scientists observed an increase in some insect species which could be due to different air conditions.
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