<b>Old `Ohi`a:</b> Pat Hart thinks he may have found the oldest broadleaf trees in the Northern Hemisphere – right in his back yard. More than a decade ago, Hart, a professor of biology at the University of Hawai`i – Hilo, began studying `ohi`a (<i>Metrosideros polymorpha</i>) at the U.S. Fish and Wildlife Service’s Hakalau Forest National Wildlife Refuge, on the windward slopes of Mauna Kea. His motivating concern was to understand whether the forest at Hakalau would have enough old-growth `ohi`a a hundred years from now to support populations of some of Hawai`i’s most endangered birds, which rely on the niches and cavities in the old trees for habitat.
His initial impression was that the old-growth trees “seemed to be falling down,” and, given the notoriously slow growth of `ohi`a, Hart said, he was worried that at some future point, not enough trees would be available to support healthy populations of the forest birds, particularly the `akepa. But after measuring the growth and death rates of young trees, Hart concluded that the proportion of old-growth `ohi`a is actually on the rise, now that cattle and pigs have been eradicated from most of the refuge. “Large trees … are generally not falling faster than they’re being replaced, which is good news for birds, trees, and people,” he said at a recent seminar.
But a funny thing happened en route to that conclusion. Hart shipped a “slice” of a recently fallen old `ohi`a to a lab on the mainland, where tests determined the age of the tree to be around 600 years. Hart also discovered that – at least at Hakalau – the age of an `ohi`a was closely correlated to its diameter: trees between 60 and 70 centimeters in diameter, commonly found at Hakalau, are probably around 400 years old.
That, Hart said, “makes `ohi`a the oldest known broadleaf trees in the United States.” What’s more, “Hakalau may be the oldest broadleaf forest in the Northern Hemisphere,” he said. “It’s a significantly ancient forest.”
<b>Food or Fuel?</b> “The amount of wheat needed to create enough ethanol to fill the fuel tank of a single SUV would feed one person for a whole year.” That statistic, cited by former Italian prime minister Romano Prodi in a speech last April, underscores the high human cost of biofuels.
And don’t take Prodi’s word for it. Worldwide, futures of vital food grains such as rice, wheat, and corn have soared under the double whammy of drought and growing demand for biofuel stocks.
“Something must be done,” Prodi said, “to ensure that both the United States and Europe stop producing fuel in competition with food…. People can no longer be allowed to starve to death in Africa simply because there are some peopled in the United States or European Union who consider that the votes of farmers or landowners are worth more than the survival of millions of men and women.”
Although today’s policies were set in motion “when we thought we were living in an energy-poor, food-rich world,” he said, “but that is no longer the case today.”
According to the International Food Policy Research Institute, based in Washington, D.C., if biofuel production ceased, the price of corn in world markets would drop 20 percent by 2009, while wheat would fall 10 percent.
<b>Fuel or Fresh Water?</b> To many, the solution to the food vs. fuel problem surrounding biofuel production lies with microalgae, a non-food crop that theoretically has the potential to yield huge amounts of biodiesel. But according to Hawai`i Natural Energy Institute researcher Michael Cooney, those believers, which include engineers and scientists, have not seriously considered the cost of water involved in turning microalgae into fuel.
Water use and extraction of oils from algae cells are the two biggest problems this crop faces, Cooney said in a recent presentation at the University of Hawai`i. And as far as he’s concerned, those two problems – which he calls the 9,000-pound gorilla and 9,000-pound Godzilla in the room, respectively – can’t be overcome cost-effectively. “Too much money is raised to areas that will not deliver,” he said.
With regard to water use, to grow enough microalgae to make one gallon of biodiesel would require nearly 3,000 gallons of fresh water, he said. That’s roughly equivalent to 464 full household-sized water heaters for one 20-gallon tank of gas, he said, adding that if the water used is recycled wherever possible, that amount could be reduced to as little as 7.2 gallons of water per gallon of biodiesel (or 1.2 water heaters per 20-gallon tank).
Even with the reduction in water use that comes with recycling, it would take many millions of gallons of water to grow the algae on an industrial scale. And, Cooney said, “It’ll take more energy to dry [the algae] than you’ll get out of it.”
Volume 18, Number 12 — June 2008
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