A “breakthrough” on deforestation is set to be the first success of the UN climate talks in Bali. Diplomats are said to be confident that the “road map” to a new climate-change treaty would contain a crucial reference to forests.

That would be an important first for a sector omitted from the Kyoto Protocol. Deforestation is recognised as the second leading cause of climate change and is responsible for a third of carbon emissions from the developing world. The move would make financial rewards for not chopping down trees part of a new climate deal.

The breakthrough emerged as the World Bank announced an initiative to fund pilot projects in rainforest nations that could become the building blocks for a much larger scheme when, and if, the road map leads to a successor to Kyoto. Wealthy countries yesterday made pledges to the £150m Forest Carbon Partnership Facility, with the UK contributing one-tenth of that budget.

“[It] signals that the world cares about the global value of forests and is ready to pay for it,” said Robert Zoellick, the World Bank president. “There is a fast-emerging consensus that if we don’t do something about forests we drastically reduce the options for combating climate change.”

But green campaigners criticised the arrangement, because it could extend carbon offset schemes to tropical forests. They said it would allow future developments, including new runways and power stations, to be justified by a forest project on the other side of the world.

Critics of the World Bank, including Oil Change and Friends of the Earth, also accuse it of tokenism however, pointing out that 90 per cent of its energy funding, £4.4bn since 2000, has gone to fossil-fuel projects which contribute to global warming.