LONDON, Oct. 4 (Xinhua) -- An experiment in Britain which transformed a forest of old trees into a giant outdoor science lab to show impact of CO2 on trees has showed startling results, British scientists revealed Monday.
Scientists at the University of Birmingham found mature oak trees increased their rate of photosynthesis in response to raised levels of carbon dioxide (CO2).
In the experiment, an old oak forest was bathed in elevated levels of CO2. Over the first three years of a ten-year project, the 175-year-old oaks clearly responded to the CO2 by consistently increasing their rate of photosynthesis.
The results, the first to emerge from a giant outdoor experiment and published in the latest edition of the journal "Tree Physiology", revealed the mature oak trees will increase their rate of photosynthesis by up to a third in response to the raised CO2 levels expected to be the world average by about the year 2050, according to the new research.
Researchers are now measuring leaves, wood, roots and soil to find out where the extra carbon captured ends up, and for how long it stays locked up in the forest.
The research was carried out at a facility of the Birmingham Institute of Forest Research (BIFoR) in close collaboration with scientists from Western Sydney University who are running a similar experiment in old eucalyptus forest. They are the world's two largest experiments investigating the effect of global change on nature.
Professor Rob MacKenzie, founder of BIFoR, said: "It's a delight to see the first piece of the carbon jigsaw fall into place. We are sure now that the old trees are responding to future carbon dioxide levels. How the entire forest ecosystem responds is a much bigger question requiring many more detailed investigations. We are now pushing ahead with those investigations."
Lead scientist Professor David Ellsworth said: "Previous work measured photosynthesis increased by up to a fifth in increased carbon dioxide. So, we now know how old forest responds in the warm-temperate climate that we have in Sydney, and the mild temperate climate of the northern middle latitudes where Birmingham sits."
Birmingham researcher Anna Gardner, who carried out the measurements, said she was excited about contributing to the first published science results of an experiment of global importance.
"It was hard work conducting measurements at the top of a 25 meter oak day after day, but it was the only way to be sure how much extra the trees were photosynthesising," Gardner added. Enditem