See the forest and the trees

With growing community concern about global warming, all sorts of new policies and projects have been proposed to reduce carbon dioxide emissions.

These range from the possible mandating of ethanol by the Queensland government to Prime Minister, John Howard's suggestion that we should seriously consider building nuclear power stations as well as wind farms.

While it may be worthwhile to consider ways of reducing carbon emissions, there is also a place for policies which promote carbon sequestration.

Actively growing trees sequest carbon dioxide and harvesting this timber moves the stored carbon from the forest to the wooden product, be it a railway sleeper or bridge girder.

Rates of carbon sequestration slow as forests age with old growth forests storing but not sequesting carbon.

But environmental activists don't much like the idea of actively managing forests as this involves cutting down trees.

So we end up using materials like concrete, steel and aluminum whose production involves lots of energy -- and lots of carbon dioxide emissions.

Indeed, early this year, the Federal Government supported the Australian Rail Track Corporation's decision to no-longer use timber railway sleepers.

In the future, the 400,000 railway sleepers it buys each year will be concrete, which according to Mark Poynter from the Institute of Foresters of Australia this will result in an extra 190,000 tonnes of carbon dioxide emissions each year.

At the recent Australian Environment Foundation conference, Mr Poynter put this in perspective by explaining that while the Victorian government has promoted wind farms as part of its renewable energy strategy (estimated to be saving 250,000 tonnes of greenhouse gas emissions per year), about 75 percent of this saving has, in effect, been negated by the decision to use concrete rather than wooden railway sleepers.

While every bit perhaps makes a difference, the really large carbon savings are in our rangelands.

Well known ecologist, Dr Bill Burrows, has calculated that grazed woodlands in Queensland alone sequest about 35 million tonnes of carbon dioxide each year.

Indeed if woodland thickening was including in Australia's official Greenhouse Inventory we might not need any more wind farms.

Incredibly, because of the way the Kyoto Protocol is framed, Australia's national carbon accounting system counts savings from the banning of broad-scale tree clearing, but not carbon savings from regrowth or woodland thickening in western NSW and Queensland.

What about counting the carbon in woody weeds converted into biochar -- a charcoal with soil ameliorant properties -- created through the type of low temperature patchy burns once practiced by Aborigines?

It is perhaps time for environmental activists as well as state and federal governments to open both eyes when it comes to global warming and start accurately considering all the opportunities and costs of carbon sequestration in our forests and rangelands.

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