The planting of new trees forms part of the Kyoto Protocol – an agreement targeting industrialised countries to reduce greenhouse gas emissions by 12.5% of 1990 levels by 2008-2012.
A growing forest can absorb thousands of tonnes of carbon dioxide and farmers can manage agricultural soils to store some of the CO2 that plants absorb from the atmosphere.
However, scientists are now claiming that newly-planted trees in these areas will not grow fast enough to soak up the amount of CO2 in the atmosphere.
Research from North Arizona University found the ability of trees to take in additional carbon depended on several factors, including the availability of other nutrients in the soil such as nitrogen.
Scientists believe nutrient levels may not support the amount of carbon absorption they had hoped for. There is also debate about the amount of C02 released by trees once they have died.
According to the New Scientist, a tree that has died and decays returns all its carbon, hydrogen and oxygen to the environment, so the effect on C02 absorption of a mature forest would ultimately be zero.
Several industry groups have contributed to tree-planting schemes, including PricewaterhouseCoopers, which has urged its 2,600 drivers to plant enough trees to counteract the CO2 emissions produced by their vehicles.
Honda car owners received a ‘tree-tube’ gift for supporting projects that absorb, neutralise and offset CO2 emissions and LeasePlan’s GreenPlan initiative enables firms to sign up to a reforestation scheme.