Because of their potential to capture and store (sequester)carbon in wood and soil, and their potential to release it if forests are cleared, forest ecosystems make an important contribution to the global carbon budget.
Many countries and organisations, including the UK Government and the Forestry Commission, are cautious about promoting carbon sequestration as a means of reducing atmospheric carbon dioxide. The scale of the potential gain is uncertain and the accounting procedures complicated. Moreover, there is a limit to the amount of carbon that woodland can sequester, and there is a risk that the sequestered carbon could be released – through, for example, felling, forest fires or outbreaks of pests and diseases.
MOVIE: Carbon sequestration
Forests and woodlands in the UK contain around 150 million tonnes of carbon, and every year they remove about four million tonnes of carbon from the atmosphere. These values need to be compared with total UK emissions of around 150 million tonnes of carbon (as carbon dioxide) every year – mainly due to the combustion of fossil fuels. So the forest carbon sink is offsetting less than 3 per cent of annual carbon dioxide emissions and the accumulated carbon stock in forests represents only about one year’s worth of emissions at current rates. The rate of carbon sequestration (four million tonnes per year) is relatively high because most of the UK’s forests are young and still growing. As forests grow older, the rate of removal will fall. Carbon sequestration is just one of the many benefits that sustainable forest management can provide.
Further information on carbon sequestration is available from the USDA Forest Service