Noxious weed fuels green-energy debate

In the race to convert crops into energy, all eyes are on giant reed, a fast-growing and hardy grass species found throughout Texas and the southern United States.

Yet, the very qualities that make the species, also known as arundo donax, attractive to the federal government as a renewable fuel source make it a noxious weed, capable of choking native plants, clogging rivers and streams and draining wetlands.

Some scientists and environmentalists say the ecological and economic risks are greater than the reward and want the Environmental Protection Agency to reconsider a nearly finalized rule that would encourage farmers to grow giant reed and other invasive grasses for biofuels production.

“We think the idea of cleaner fuels is great,” said Janice Bezanson, executive director of the advocacy group Texas Conservation Alliance, “but we do not want to create a monster.”

Invasive species

The conflict illustrates the complexity involved in reducing the nation’s dependence on oil and gas with a new generation of biofuels that are made from algae, rice hulls, wild grasses and wood pellets rather than corn and other food crops.

The government also is counting on such fuels as a way to reduce emissions linked to global warming, a goal usually lauded by environmentalists.

This time, however, activists are warning that the use of invasive species may bring unintended consequences. Exotic species already cost the nation at least $120 billion each year, according to the National Wildlife Federation, and nearly half of the threatened or endangered plants and animals in the United States are at risk, in part, because non-native pests have altered their habitats.

Can’t plant it in Texas

As benign and even lovely as it may seem, giant reed has menaced several states, including Texas, which classifies it as a noxious weed – a designation that means it cannot be planted in the state. Even then, the thirsty perennial, which can grow in dense stands as high as 30 feet, has taken hold, consuming large amounts of water from the Rio Grande and Pecos River and blocking the flow of the Nueces River.

The problem became so acute along a 30-mile stretch of the Nueces that landowners and other volunteers spent 11 weeks last year pulling arundo sprouts by hand. State and local officials also employed a helicopter to spray herbicide over nearly 200 acres.

In California, which also is battling giant reed, officials estimate the cost of eradication is between $5,000 and $25,000 an acre.

Giant reed is native to India and was introduced into the U.S. in the 1800s for erosion control. The plant can spread from a single underground stem or stalk fragments that grow roots and form new clones, typically along streams and irrigation canals.

Those opposed to the government’s plan to grow the wily weed say the plant could escape and overrun nearby farms and natural lands. Instead they want the government to encourage the use of native plants and grasses that also provide habitat for wildlife.

“Arundo was designed to survive,” said Wilfred Korth, a park ranger near Victoria and member of the Texas Aquatic Plant Management Society. “Every bit will create a new plant, and it chokes everything else out.”

‘Legitimate concerns’

Ironically, climate change could contribute to the spread of giant reed and other invasive species, which may have a competitive advantage in places disturbed by droughts, floods and other extreme events that scientists say will increase in intensity and frequency as the planet warms.

Joshua Yuan, a plant pathologist at Texas A&M University, said growing giant reed as a biofuel crop still could be safe if introduced under the right conditions.

“There are legitimate concerns because there is no natural enemy to mitigate the growth of arundo,” Yuan said. “How you manage the crop is important.”

The U.S. Department of Energy has awarded a $1.8 million grant to Yuan to create a tobacco plant packed with terpenoids, a hydrocarbon that can be used for fuel. If the project is successful, he will receive $2 million in additional funding to do the same with giant reed, a higher-producing species.

The research effort is part of the federal push to meet requirements set by the Bush administration, including the production of 21 billion gallons of biofuels a year by 2022. Analysts, however, say it is unlikely that goal will be reached, in part, because no one has shown that fuels from biomass, plant matter grown for energy use, can be made profitably.

Regardless, a group of more than 200 biologists and botanists urged the Obama administration last week to avoid using invasive species in the production of biofuels. Their concerns include the use of federal dollars to incentivize farmers to grow giant reed and even expand its cultivation into new areas.

“It is much cheaper and easier to take the steps to prevent an invasive escape than it is to deal with it after it has occurred,” the scientists wrote in a letter to federal officials.

matthew.tresaugue@chron.com; twitter.com/mtresaugue