By Alister Doyle, Environment Correspondent

OSLO, Nov 28 (Reuters) - The world has surpassed a U.N. goal of planting 1 billion trees in 2007 to help slow climate change, led by huge forestry projects in Ethiopia and Mexico, the U.N. Environment Programme (UNEP) said on Wednesday.

The global tree-planting drive, inspired by Kenyan environmentalist and 2004 Nobel Peace Prize winner Wangari Maathai, is meant to counter deforestation from logging and the burning of forests to create farmland.

"An initiative to catalyze the pledging and the planting of one billion trees has achieved and indeed surpassed its mark," UNEP head Achim Steiner said in a statement on plantings by governments, companies and individuals.

"It is a further sign of the breathtaking momentum witnessed this year on the challenge for this generation -- climate change." Trees soak up carbon dioxide, the main gas blamed for stoking global warming, as they grow.

UNEP said Ethiopia appeared to be the runaway leader with 700 million trees planted in a national reforestation drive. Only 3 percent of Ethiopia is now forested, down from 40 percent centuries ago.

Other top planters were Mexico with 217 million trees, Turkey 150 million, Kenya 100 million, Cuba 96.5 million, Rwanda 50 million, South Korea 43 million, Tunisia 21 million, Morocco 20 million, Myanmar 20 million and Brazil 16 million, it said.

The billion-tree target was set in Nairobi in November despite criticism that it would be impossible to verify. It was declared passed less than a week before the start of a Dec 3-14 meeting of the world's environment ministers in Bali, Indonesia.

"You responded beyond our dreams," said Maathai. "Now we must keep the pressure on and continue the good work for the planet. Plant another tree today in celebration."

China, Guatemala and Spain were expected soon to announce new plantings of millions of trees, UNEP said.

Indonesia plans to plant 80 million trees in one day before the Bali conference, which is meant to launch two years of talks to work out a new international deal to fight global warming.

UNEP says it checks planting pledges, which now cover 1.5 billion trees, to see if they sound credible but does not ensure all are planted. It said the totals were still being collated.

-- For Reuters latest environment blogs click on: http://blogs.reuters.com/environment/ (Editing by Robert Woodward, Reuters messaging:

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