Wild untouched forests store three times more carbon dioxide than previously estimated and three times more than plantation forests.
A world-first study of “green carbon” by scientists from the Australian National University (ANU) looked at natural forests’ role in climate change. They say our forests have been underestimated as a solution against global warming.
Despite this massive difference in carbon storage, current world bodies looking at climate change (IPCC and Kyoto Protocol) don’t distinguish between plantations and untouched forests; a forest’s ability to store CO2 is only based on plantation forest estimates.
A co-author of the report, Professor Brendan Mackey, estimates that around 9.3 billion tonnes of carbon can be stored in the 14.5 million hectares of eucalypt forests in southeast Australia if they are left undisturbed. The largest stocks of carbon are found in the tall wet eucalypt forests of Victoria and Tasmania where the biomass of forests supporting trees up to 80 metres tall can contain more than 1200 tonnes of carbon per hectare! This is up to 10 times more carbon per hectare than previously realised.
Natural forests store more carbon and for much longer. Plantations are grown to be cut down every 12 – 30 years. Natural forests are also much more resilient to climate change and disturbances than planted tree crops.
The carbon stored in forests includes the thick understorey, the rich soil carbon, the wildlife and the trees. This store of biomass is about three times the amount in the atmosphere.
About a third of greenhouse gases in the atmosphere today is from past forest clearing and 18% of annual global emissions is from continued forest clearing.
The report says that when a logged forest regrows, it stores about 60% of what the original forest would have, so stopping further logging of southeast Australia’s eucalypt forests is the equivalent of preventing emissions of 460 million tonnes of carbon dioxide a year for the next 100 years.
Allowing logged forests to regrow to their natural carbon storage capacity will avoid emissions of 136 million tonnes of carbon dioxide a year for the next 100 years. This is about 25% of Australia’s total emissions in 2005.