Researchers bathed plots of pine trees in extra carbon dioxide every day for 10 years and found that while the trees grew more tissue, only those that received the most water and nutrients stored enough carbon dioxide to offset the effects of global warming.
Ram Oren, the ecologist who led the project, said the research suggested that planting more trees would not be successful in slowing the pace of climate change. "More trees don't necessarily mean less carbon dioxide," he said. "Planting trees is not going to do a whole lot to decreasing carbon concentration.
"What we're finding is that extra carbon very quickly goes back into the atmosphere if there are low nutrients and water available.
"And we are not going to be able to increase the capacity of forests to hold carbon, because we couldn't fertilise such large areas or provide sufficient water. It would cause such pollution that the consequence would be much worse than carbon dioxide enrichment in the atmosphere."
But Ru Hartwell, the director of Treeflights, an offsetting company planting trees in Wales and Peru, said: "There are problems with tree planting but it is only one way in which we are going to get on top of the problems of global warming. I have complete faith that tree planting is positive and we should not just chuck away our spades and do nothing."http://www.telegraph.../ncarbon119.xml