But it is part of a US trend to feature films about nature and the assaults on it.

The 11-day festival in Washington, which runs through Sunday, takes the widest possible view of what makes an environmental film, according to its founder, Flo Stone.

Stone said in an interview: "If you interpret the environment as we are ... it's about perception of your surroundings, of the world, of your own community, learning the incredible excitement of natural history and of life itself."

There are certainly mainstream successes - including the Academy Award-winning March of the Penguins - among the 100 films shown at theatres, museums, think-tanks and embassies around the US capital.

But there are also frankly quirky films that might not find an audience any other way.

Take on life
   
One such entry is The Concrete Revolution, directed by Xiaolu Gue, a young woman who turned her camera on construction workers and others in Beijing as the Chinese capital gears up for the 2008 Olympics.

The film March of the Penguins is
a mainstream success

Billed in the festival programme as a "meditation on life in a rapidly developing new China", the hour-long film is undeniably affecting, especially when one country-bred worker weeps quietly as he talks about leaving his wife and family in his village as he works to demolish old homes in the city.

Other films may not be so easily classified as environmental, such as Swiss filmmaker Christian Frei's trio of films, including The Giant Buddhas, which chronicles the destruction of the massive statues at Bamiyan by Afghanistan's former Taliban government.

"It's somewhat astonishing," Frei said, when asked in a telephone interview how his films fit into the environmental film festival.

"When I was invited, I was sort of wondering why. I'm not really an environmental filmmaker, there's no pollution. ... Everything is environment, if you want."

Human reaction

That also held true for Filip Remunda, of the Czech Republic, whose film, Czech Dream, documents an elaborate hoax perpetrated by Remunda and Vit Klusak on the Czech public.

"If you interpret the environment as we are ... it's about perception of your surroundings, of the world, of your own community, learning the incredible excitement of natural history and of life itself"

Flo Stone,
Environmental Film Festival founder

Working with an ad agency, they promoted an imaginary superstore they called Czech Dream. When the promised opening day arrived, would-be consumers arrived to find nothing but a flimsy facade, and the filmmakers recorded their reaction.

"The reaction was various: some very angry people, some who really understood the essence of the project," Remunda said by telephone.

"They found it either as a joke or a message."

The Washington film festival, set up in 1993, is one of a handful in the US devoted to environmental subjects.

One of the oldest is the International Wildlife Film Festival in Missoula, Montana, now in its 29th year.

Jackson Hole, Wyoming, also has a wildlife film festival, and the American Museum of Natural History in New York City has the Margaret Mead Film and Video Festival, which has screened many environmental films.

Contemporary issues

In New York state, the Finger Lakes Environmental Film Festival runs from 30 March to 6 April.

These festivals are important for environmental filmmakers, according to director Gregory Greene, whose film, The End of Suburbia, deals with the growing appetite for oil as it becomes harder to find.

"For us as filmmakers ... our ability to reach the general public is really dependent on film festivals like this," Greene said in a telephone interview from Toronto.

"It is the way that we can reach the general public ... and warn the general public about what we're advocating."