Australia has been found to be the home of the world’s most carbon-dense forests, according to researchers from the Australian National University (ANU).

The researchers studied biomass data from 132 forests from around the world to discover the regions that stored the most carbons. Their findings overturn conventional thinking about the carbon density of different forest types.

Until recently, tropical rainforests were held to be the most carbon-dense; however, the research team found that the world’s most carbon-dense forest that has currently been measured is a mountain ash forest in the Central Highlands of Victoria.

The research team—Professor Brendan Mackey, Professor David Lindenmayer, and Dr. Heather Keith of the Fenner School of Environment and Society at ANU—recently published the results in the US-based Proceedings of the National Academy of Sciences.

Professor Mackey said the forest in Victoria, which is part of the water catchment for Melbourne, was a clear winner for the world’s most carbon-dense forest and he suggested a number of reasons why this was so.

“The amount of carbon stored in an ecosystem depends on the rate that plants photosynthesise and grow, but that’s countered by the rate biomass respires and decays. These forests occur at an intersection of those environmental conditions which are conducive to high rates of plant growth and, because they’re cooler, slower rates of decay.

“Additionally, the trees in this forest are very old – they’ve been there for at least 350 years, growing dense heavy wood. That’s important because the amount of carbon stored is due to volume and density. On top of that, these trees have not been subject to intensive land use, such as logging.

“Finally, it involves the way the forests have evolved in response to fire. If they get an intense fire that kills the tree, you haven’t lost all of the carbon – most of it is in the trunk, branches and roots, and much of it remains after a fire, even as dead wood. Many trees survive fire in less intensely burnt patches, plus new groups of trees regenerate. Over time the total amount of carbon building up can be very large, resulting in a complex forest,” said Professor Mackey.

The forest in Victoria is classified as part of the moist temperate forest type. Other Australian forests of a similar type also scored highly on carbon density as did similar types of forests from elsewhere, including the Pacific Coast of North America, Chile, and New Zealand.


-  Katrice R. Jalbuena

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Sources:

¹ http://news.anu.edu.au/?p=1297
² http://www.anu.edu.au/index.php