Study Of Pines + CO2 Poses Big Questions, Problems For Sequestration - WP

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In the FACE rings with high carbon dioxide, "it's as though we had put the loblollies inside a greenhouse," said Heather McCarthy, a biologist at Duke. "Within two years of their exposure to higher levels of carbon dioxide, the trees' needles hit a major growth spurt. The pines reached maturity faster than their counterparts. They produced cones at younger ages than their cousins growing in lower carbon dioxide conditions. And the cones contained many more seeds" -- as much as 300 percent more.

McCarthy placed buckets beneath the pines in the experimental areas. Like old-time Southern weavers who harvested loblolly pine needles for intricate coiled baskets, she collected needles shed by the pines. She also sampled needles on the branches. She found that the pines exposed to high levels of carbon dioxide had many more needles, at least 17 percent more, than untreated pines. "It's clear that high carbon dioxide levels are causing these loblolly pines to 'make' more needles," McCarthy said.

But the faster growth may not continue indefinitely, because rising carbon dioxide levels and temperatures are likely to have other effects, including reducing rainfall. The trees' growth is likely to diminish over time, Duke scientist Ashley Ballantyne said, "due in part to the hot, dry weather that may be more common then." Loblolly growth in the Blackwood division, where Ballantyne did his research, "seems to be related to soil moisture -- water available for use by the trees -- in addition to carbon dioxide," he said. "Increasing temperatures will likely cause a decline in soil moisture, eventually suppressing tree growth."

In gold rush terms, rising carbon dioxide creates a loblolly boom, but decreasing soil moisture ushers in a bust.

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http://www.washingtonpost.com/wp-dyn/content/article/2005/11/20/AR2005112000788_2.html?nav=hcmodule

...suggests that the initial increase in productivity resulting from increased CO₂ declines after several years. This makes sense-- biomass accumulation and production/respiration budgets respond to many selective forces, not just ambient CO₂ levels. Also, we've known for some time that the trade-offs between carbon fixation efficiency and water use efficiency are likely to cause problems as global climate responds to increasing atmospheric green house gas concentrations.

Anybody told Fred Singer or AEI yet?

Didn't think so . . .