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This article originally provided by Ventura County Star
December 14, 2006
Substituting grass for gasEnergy future might depend on reviving the past
By John Krist
If asked to choose the plant that best symbolizes the wild landscape of North America, what would you select?
The coast redwood, tallest living thing on the planet, rising from moist Northern California forests to tickle the bellies of passing clouds? Or the bristlecone pine, longest-lived of all trees, some gnarled specimens having endured the bitter cold, dry wind and fierce sunlight of a Great Basin mountaintop for more than 40 centuries? Perhaps you would favor the American chestnut, stately keystone of the dense eastern woodland that once sprawled across 200 million acres from Maine to Florida?
Each would have its champions, as would other candidates. But for sheer ubiquity and ecological importance, the most appropriate choice for botanical icon would be a blade of grass. For it was grassland, more than any other type of plant community, that dominated North America two centuries ago when European and American explorers first crossed the continent's interior. It was grassland that sustained the great wandering herds of grazing animals, the bison, pronghorns and elk, that stunned early explorers and settlers with nearly unfathomable abundance and which figure so prominently in our national mythology.
It was grasslands, in fact, that made possible both the development of agriculture and the urban civilizations that for millennia have risen and rested upon farmers' backs. And grasslands might hold the key to the future as well.
New research suggests that one of the most promising untapped domestic sources of fuel in the United States lies not in rock formations beneath Alaskan tundra or offshore waters. Nor does it lurk in coal beds under Allegheny summits. Instead, it may be found in the living fabric of the prairies that Americans have disdained, exploited and abused for nearly two centuries.
Grassland dominated the pre-settlement American landscape. Biologists estimate that prairie covered nearly 40 percent of North America in the early 19th century, more of it than any other single plant community.
But grasslands hardly exist anymore in their natural state, and conservation biologists consider them to be among the most imperiled ecosystems on Earth. On the Great Plains, barely 1 percent of the original prairie ecosystem remains intact. Most of the rest has been plowed and planted in single-crop stands of corn, wheat, rye and soybeans, or else degraded and abandoned to an unpalatable mess of exotic weeds.
Millions of acres of former prairie is devoted to corn, the most widely produced crop in America. And increasingly, that corn — along with other crops grown in basically the same manner — is seen as a way to blunt American dependence on petroleum. Many energy experts believe home-grown crops converted to ethanol might supplant oil derived from dwindling reservoirs in politically inconvenient locations.
But corn, although widely available and produced in staggering quantities by heavily subsidized growers, is not the most efficient source of plant-based liquid fuel. Nor are switchgrass, special tree hybrids or other darlings of the conventional ethanol industry. According to a study conducted by researchers at the University of Minnesota, that title belongs to the sort of grassland plants that corn and other crops largely replaced as farmers plowed the prairies.
Biofuels derived from a mixture of native grassland perennials, they found, yield up to twice as much usable energy per unit of land as corn-based ethanol. There are several reasons for the greater energy yield, but the most important is this: Grassland plants don't need tilling, fertilizing, watering or protection from pests, all energy-intensive activities that offset much or all the energy produced when grain is converted to fuel.
In addition, according to the study (which is reported in the December issue of Science), grassland plants can be a "carbon-neutral" fuel. Corn production and ethanol combustion all contribute greenhouse gases to the atmosphere. But grassland plants actually pull carbon from the air and store it in their roots, which are not harvested to produce fuel (only the above-ground portion is removed, and it grows back naturally). Over time, that carbon sequestration offsets any carbon released when the fuel is burned, the researchers concluded.
Much of what accompanies modern energy production — decapitated mountains, slag heaps, vast networks of drill pads and pipelines, slurry ponds — is ugly, dangerous and destructive.
Imagine, though, that a significant part of that production involved restoring millions of acres of once-vibrant prairie to its natural state, and then periodically mowing it as bison once did.
— John Krist is a senior reporter and Opinion page columnist for The Star. His e-mail address is jkrist@VenturaCountyStar.com.
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