ARTICLE: Save the forests: they are crucial to reducing carbon dioxide

Brendan Mackey
The Age, August 7, 2007

Remarkably, both the Australian Government and Labor Opposition have now realised the importance of natural forests to solving the global warming problem. This is a good thing because the Kyoto Protocol is unfortunately blind to the role played by natural forests in the global carbon cycle.

But there is some way to go before Australia has consistency between its national and international forest-climate policy responses. The recently announced Labor forest policy for Tasmania does not recognise the link between forests and the global warming problem.

The Australian Government has recognised this link but is attending to forest-climate issues only at the international level. Both policy positions need to be reconsidered as they reflect a lack of scientific understanding about the role of natural forests in helping to regulate the concentration of greenhouse gases in the atmosphere. This is not surprising as our understanding of carbon in natural forest has been transformed in recent years through scientific research and little of this new knowledge has yet filtered into popular literature and policy circles.

The forest debate in Australia remains dominated by conflict between those who see the forest as a source of raw material (woodchips) and those who value the forest left intact for nature conservation. We need to update the forest debate to reflect current concerns and the growing imperative that we solve the global warming problem. This means that forest policy, nationally as well as internationally, must begin to reflect the role of forests as part of a co-ordinated greenhouse-gas mitigation strategy.

In addition to reducing our use of fossil fuel, the other major mitigation strategy is to increase the removal of carbon dioxide from the atmosphere by natural processes through protecting and restoring the world's natural forests.

Natural forests are an important part of the global carbon cycle. They are buffers that soak up excess carbon dioxide in the atmosphere and store it in the biomass of trees and in the soil. Forests are an essential natural mechanism for stabilising atmospheric concentrations of carbon dioxide in the short and long term.

One hectare of mature, tall, wet forest can store the equivalent of 5500 tonnes of carbon dioxide. This is about the same as the annual carbon dioxide emissions from 1300 cars. Even less productive dry forests and woodlands store significant amounts of carbon. Most of the carbon in a natural forest is stored in the woody biomass of big old trees, dead wood on the forest floor, and in the soil. It is easy to forget about the carbon below ground: in the tree roots and associated fungi, other micro-organisms and decomposed plant material. These represent significant stocks of carbon that are continually replenished through natural ecosystem processes.

Forests contain about three to four times more carbon than is now in the atmosphere. About half the world's forests have been cleared for agriculture and human settlement. Much of what is left is commercially logged for timber products; especially woodchip for pulp-based products.

Forests that are commercially logged store about 30 per cent to 40 per cent less carbon than unlogged forests. If we were to halt further deforestation and allow the world's forests that have been logged to naturally regrow, the amount of carbon taken up and stored in these ecosystems would make

a significant contribution to solving the global warming problem. Plantation timber can be grown on land that has already been cleared and used to meet the demand for pulp and related wood-fibre products.

If global warming really is the mother of all environmental problems, then perhaps the time has come to bring to an end the clearing and logging of natural forests. This will make a significant and cost-effective contribution to solving the global warming problem. We must not forget that the laws of science apply universally and do not recognise political boundaries. Whether a natural forest is in Tasmania, Victoria or Papua, it performs the same kind of role in the global carbon cycle and in helping to regulate atmospheric levels of carbon dioxide.

All the signs are that sooner or later the carbon that is stored in natural forests will be assigned an economic value and become part of the global carbon market. When this happens, companies will be allowed to offset some of their carbon emissions by investing in forest protection. Once the carbon in forest ecosystems has a market value, companies that are fossil-fuel hungry (such as steel and aluminium producers) will seek to take advantage of offset opportunities in natural forests to give themselves more time to maintain production levels while making the transition to greenhouse-friendly energy sources.

For this reason, I predict that as the impact of global warming increases in the coming years, the market values of carbon in natural forests will dramatically increase. It will be ironic if Australia's natural forests are taken out of wood production not by conservationists but by international corporations.

Of course, before this can happen in a substantial and enduring way, the international rules have to change. But this process has already started at least in terms of recognising the need to prevent deforestation in developing countries, and voluntary investments in forest conservation are already occurring.

Brendan Mackey is a professor of environmental science at the Australian National University and an expert in ecosystems and the impact of climate change on biodiversity.

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