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Scientists study carbon ‘sinks’ in our forests

Mountain forests absorb some of the 5 tons of emissions from our SUVs

Oh, the things you do without fully realizing it. Take those errands to the post office, the grocery store, and that occasional trip to Vancouver.

Driving a sports utility vehicle on these trips? Don’t be embarrassed. Many people do. But even at the 18 miles per gallon of a Chevy Suburban, which is better than most SUVs, that’s a lot of carbon dioxide spewed into the sky. Figure five tons for every 10,000 miles.

Where does the carbon dioxide go? Into the atmosphere, what one scientist, Jerry Mahlman, calls "our ultimate garbage dump." As a species we add an estimated seven billion tons of carbon into the atmosphere each year, while up to another two billion tons is added as a result of deforestation of such places as Amazonia.

And just think: the Chinese are only now getting refrigerators, SUVs, and so forth.

North Americans have especially high-carb diets. The United States, with only 4 per cent of the population, directly contributes 25 per cent of the carbon into the atmosphere.

Yet it’s not quite that simple, either. Carbon dioxide does not necessarily stay in the atmosphere. The carbon can be soaked up by oceans and plants. These are what scientists call carbon sinks.

But how much carbon these sinks hold is still unclear. For example, forests both emit and soak up carbon. When they are burning or decaying, they give off carbon. When they are young and growing, they absorb it from the atmosphere.

Conventional carbon-measuring equipment works fairly well in flatter areas. But in areas where forests are found mostly in the mountains, these conventional techniques are inadequate.

To help get a better handle on the carbon-uptake from these forests in Colorado, a former military cargo plane, a C-130, has been used this summer to fly over the Front Range at altitudes of 1,000 to 3,000 feet. Where the plane once carried Jeeps, its belly is now packed with specialized instruments that are used to measure carbon, methane, and other gases.

"It’s like a flying laboratory," explains Dennis Ojima, a research scientist in Fort Collins at the National Research Ecology Laboratory, one of several agencies involved in the experiment,

Of special interest to scientists conducting this experiment is the site of the 150,000-acre Hayman fire southwest of Denver. Most burn areas, says Dave Schimel, a scientist at the National Center for Atmospheric Research in Boulder, are too small to get adequate readings of how a forest absorbs or emits carbon soon after a fire. The Hayman area is large enough.

Figuring out where the carbon is going could also be worth money under an international treaty such as the Kyoto Protocol. If a country could prove that its forests suck up carbon, that uptake could be credited against the emissions caused by the burning of fossil fuels.