Hannah had climbed the tree to support the community of immigrant farmers from Mexico and Central America who had created and tended this 5.6-hectare oasis - the largest urban farm in the country - since 1992, after getting a permit to cultivate what had been an abandoned lot. They grew 150 species of vegetables and fruits, including avocados, mangoes and maize and heirloom varieties from their homeland - all fresh organic produce that fed 350 poor families. The farmers ran it by the Mexican ejido system, as communal land, with markets and cultural events open to the public. The farm also absorbed some of the vast amounts of carbon dioxide emitted by the city.

In 2003, the city sold the land to a developer who later served an eviction notice. To draw attention to the situation, Hannah sat in the tree for three weeks with activists Julia Butterfly Hill and John Quigley. 'I'm very confident that it is the morally right thing to take a principled stand in solidarity with the farmers,' said Hannah.

The fight for the farm is just one part of Hannah's personal crusade to protect the environment. A veteran of the film industry, she has over 60 credits to her name and is still busy acting. But she invests the rest of her time in promoting a green lifestyle. She recently began producing weekly

5-minute videoblogs (found online at dhlovelife.com) - 'guerrilla-style', as she puts it, without benefit of corporate sponsorship or a film crew. These inspirational mini-documentaries show people making choices that help the Earth in everyday life, covering green cosmetics companies, sustainable architecture, biodiesel, Rwanda's endangered gorillas and, of course, the South Central farmers.

Hannah lives her philosophy, too: her house is run on solar power in Colorado's Rocky Mountains; she grows much of her own food; and she drives a biodiesel car. 'It's not a matter of a political belief or an environmental stance. It's really just common sense,' said Hannah.

Sadly, there's only so much that common sense and star power can do. The South Central sit-in hit headlines, and other celebrities - including actors Martin Sheen and Leonardo di Caprio - supported it. But the eviction went ahead in June, the activists were forcibly removed and arrested, and the farm was bulldozed.

But the farmers are not giving up. They still hold vigils at the site and are looking for a way to restore the farm, legally and financially, while starting to cultivate another urban garden on a 3-hectare plot provided by the city. And Hannah still stands by them. 'The subsistence farmers are from one of the poorest communities,' she said. 'This farm should be a model for sustainable urban agriculture. It needs to be replicated, not eradicated.'