* Greens party hurt by tax-hike calls and vegetarian ideas
* Down to 10 percent from 14 a month ago
* Greens' slide most dramatic pre-election poll changes
By Erik Kirschbaum
BERLIN, Sept 5 (Reuters) - Support for the German Greens has slumped to its lowest in four years just over two weeks before a federal election, with voters put off by the party's plans to increase taxes on the rich and its attempt to persuade people to eat less meat.
The Greens' two-point drop to 10 percent in a survey by FGW released on Thursday makes it even less likely that the centre-left can defeat Chancellor Angela Merkel in the Sept. 22 vote.
The erosion of the environmentalists' support, from a peak of 23 percent in mid-2011, is the most remarkable trend of a campaign where Merkel's centre-right has polled a steady 45 percent for months, giving her a slim but consistent lead.
Party leaders put a brave face on an accelerating downward trend that has seen them slump from 14 percent in the FGW poll since early August. They last hit 10 percent in late 2009 before surging to record highs after Japan's 2011 nuclear disaster.
"You can believe in opinion polls if you want but I'm convinced it will be the voters who decide on Sept. 22," said Greens co-leader Katrin Goering-Eckart at a news conference.
Juergen Trittin, co-leader of the world's most successful environmental party - which spent seven years in power with their SPD allies from 1998 to 2005 - said he was "relaxed" about the poll numbers.
"We've seen remarkable opinion polls before elections in the past too," said Trittin, referring to 2002 when the SPD and Greens came from far behind in polls to beat the conservatives.
The Greens have evolved from a fringe pacifist movement in the 1980s to a mainstream party with broad appeal.
But pollsters said many voters found the party's policies too intrusive. As well as raising taxes on the rich, it wants to slow down German drivers by expanding a 30 km/h speed limit. It has also advised people to stop eating meat one day a week.
The Greens lost one of their main rallying cries - the call to turn off nuclear power plants in Germany - when Merkel unexpectedly decided to close down the country's remaining nuclear power stations by 2022 after Japan's Fukushima disaster.
The Greens have a tradition for self-inflicted wounds. They were flying high before the 1998 election until a row broke out over a proposed hike in fuel tax at a party rally in Magdeburg that sent support plunging to six percent. (Reporting by Erik Kirschbaum; Editing by Stephen Brown and Andrew Heavens)