MARYSVILLE, Ohio -- Honda Motor Co. is constructing wetlands to cleanse water that flows through its property. Soybeans grown on company land are harvested and shipped overseas for sale. Willows that sprout up are donated to feed a moose at a nearby zoo.

And -- oh yes -- Honda also builds automobiles.

Automakers around the nation are involved in more than just pumping out cars and trucks. Many have taken steps to improve the environment near factories, save energy, make a little extra money and benefit the local community.

Even with U.S. auto sales at 17-year lows, the Big Three are keeping up the effort as they battle for survival.

David Cole, chairman of the Center for Automotive Research in Ann Arbor, Mich., said environmental and energy-saving moves are prudent even in tough economic times because modest investments can result in significant energy savings and avert costly environmental fixes.

"It's almost small change," Cole said. "But it still makes economic sense."

Ford Motor Co. has installed a "living roof" on its truck plant in Dearborn, Mich. The 10-acre crown is comprised of sedum, a drought-resistant ground cover that extends the life of the roof, reduces storm water runoff into a nearby river and lowers heating and cooling costs.

General Motors Corp. is putting a solar roof on its Baltimore engine plant, joining GM facilities in Spain and California.

Chrysler LLC has teamed up with Michigan State University to turn a once-polluted industrial site near Detroit into a research lab for the development of biofuels. Sunflowers, canola, switchgrass, corn and soybeans are growing to demonstrate that crops that can be used for ethanol or biodiesel can flourish on such sites.

At the Honda plant in this central Ohio city, workers scavenge trash bins for materials that can be recycled, said Honda spokesman Ron Lietzke. The company has reduced the amount of waste it sends to landfills by more than half since 2000.

Honda recently completed one wetland on its 8,200-acre property and is in the process of building a second at a total cost of $800,000.

Storm water runoff from the roofs and parking lots at Honda's research center is channeled into the existing wetland. As the water slowly snakes through cattails and other plant life, sediment drops out and a cleaner stream flows into Big Darby Creek, home to 37 rare and endangered species. The second wetland will filter fertilizer from water that flows onto Honda property from neighboring farms.

"How do you build a wetland? You move a lot of dirt," said Greg Morgan, staff engineer with Honda's environmental group.

The existing wetland, in the shadow of the research center and a factory that churns out 444,000 vehicles a year, has attracted dragonflies, frogs, muskrats, herons, mallards and ospreys.

As he drives around the property, Morgan points out some of the more than 11,000 pin oaks, sycamores, sweet gum and sunset red maples that have been planted next to a creek. Honda hopes the trees will help regulate the water temperature, reducing algae blooms and stress on fish and other aquatic life.

Nearby, soybeans grown on Honda property are processed at the automaker's soybean plant. Honda ships the soybeans to markets in the United States, Europe and Japan. South Korea will soon join the list of importers.

"Rather than being a company that is tolerated, we want the community to take pride in our factories," Lietzke said.

John DeCicco, senior fellow for automotive strategies with the Environmental Defense Fund, said companies around the country are taking steps to protect the environment in areas they can control.

Pressure from regulatory agencies and advocacy groups gives a nudge to some companies, but others do it without regard for those things, DeCicco said

"I'm very encouraged," he said. "It reflects a maturation of environmental concern from say a generation ago."

GM is stepping up its recycling campaign, shooting to double by 2010 the number of its factories that send no waste to landfills. Last year, the automaker saved $5 million by using landfill gas to generate electricity, and it made more than $1 billion by selling scrap metal from its factories.

GM spokesman Dan Flores said GM's environmental and energy-saving moves enable the company to operate more efficiently and reduce costs.

"Having an environmental focus is a greater priority for everyone," Flores said. "It makes sense from the bottom line as well."