Crucial options were left out of last year's energy bill, advocacy groups say, and policymakers are looking to remedy the exclusion. The Energy Independence and Security Act of 2007 has come under fire lately, just five months after President Bush signed it into law.

Most of the controversy surrounds the law's establishment of an aggressive renewable fuels standard, which requires the country to increase ethanol production almost eight-fold by 2022. With food prices soaring, some experts worry the new RFS will exacerbate high costs.

In anticipation of such an outcome, the governors of Texas and Connecticut have petitioned the Environmental Protection Agency to grant them waivers, excusing their states from fully meeting the required ethanol production rates in the new RFS.

Another group criticizing the RFS, though, doesn't oppose the measure itself, just the fuels it accepts as "renewable." Currently, the law does not allow woody biomass gathered from federal forest lands to be used in making fuel to meet the RFS.

This includes wood, brush, thinning, chips and logging residues. If the definition is not changed, a great deal of available fuel sources could go to waste, said Rep. John Shadegg, R-Ariz.

"In my state, we have lots of biomass that could be used for fuel," Shadegg said Tuesday at a hearing examining the RFS in the House Energy and Air Quality Subcommittee. "Unfortunately, (because of) the definition of 'renewable' in the latest energy bill - much of that biomass cannot be used."

Feedstocks like woody biomass could potentially be used to produce cellulosic ethanol, or biofuels derived from non-food sources. The new law requires that 21 billion of the 36 billion gallons mandated by 2022 come from non-food feedstocks.

Excluding federal woody biomass will make it more difficult to meet that requirement, said Rep. Stephanie Herseth Sandlin, D-S.D.

"I think this is a misguided policy that squanders an available source that could produce home-grown fuel," she said.

The amount of woody biomass that could be gleaned from forests is significant. According to a 2005 study conducted by the U.S. Department of Agriculture and the Department of Energy, 60 million dry tons could be retrieved from U.S. forestlands each year from fire-prevention operations alone.

Sandlin has introduced a bill, the Renewable Biomass Facilitation Act, which would amend the RFS by allowing the inclusion of woody biomass from federal lands to count as a renewable feedstock. Passing the measure will not harm federal forests, she said.

"It is consistent with the forest plan for (any particular) forest," Sandlin said. "Anything that's removed as part of approved preventative treatments for reducing hazardous fuels or for preventing insect infestations or disease would count toward the RFS."

If the bill is not enacted, trying to follow the original RFS guidelines could prove impossible, said Rep. Bart Stupak, D-Mich.

"There may be situations where a mill doesn't know where one or another tree came from," he said. "You can see the nightmare this provision would provide, especially for those of us from timber-based economies."

But allowing the use of these feedstocks could be harmful to the environment, said Nathanael Greene, a senior policy analyst for the Natural Resources Defense Council, a non-profit environmental group.

In general, the organization does not oppose the use of woody biomass to produce fuel, but changing the RFS as Sandlin recommends could lead to the exploitation of forests, Greene told United Press International.

"(This bill) would take away all the restrictions," he said.

In addition, actually collecting and transporting woody biomass from federal forest lands, spread all over the country, could prove to be an inefficient use of energy and the materials. Many small programs already utilize the biomass for local needs, such as heating public buildings, Greene said.

Biorefineries, though, will need ever increasing and readily available sources of fuel feedstocks as the RFS pushes them to produce more fuel, and organizations like NRDC worry this will eventually lead to the conversion of federal forests into fuel plantations.

"The demand (will) launch economic incentives that will drive biorefineries to put more pressure on the foresting community to pull materials out (of forests)," Greene told UPI.

Despite these concerns, the bill has received wide bipartisan support so far.

"We have a list of geographically and ideologically diverse co-sponsors, and the (Energy and Air Quality) Subcommittee gave the bill a warm reception (Tuesday)," Betsy Hart, Sandlin's press secretary, told UPI. "We feel we have common sense on our side and that our bill has addressed all the outstanding issues."