The UN's Durban conference on climate change failed to make enough headway in efforts to curb deforestation, experts warned, saying forest preservation plays a central role in the global warming debate.

After 14 days of marathon talks in the South African city, the conference on Sunday approved a roadmap towards an accord that for the first time will bring all major greenhouse-gas emitters under a single legal roof.

If approved as scheduled in 2015, the pact will be operational from 2020 and become the prime weapon in the fight against climate change.

"Durban has failed to deliver progress on fundamental issues like social and environmental safeguards, and on strict rules to ensure that global deforestation is reduced," said Lars Lovold, head of Norway's Rainforest foundation.

One of the main decisions taken at the 2010 Cancun climate conference in Mexico was to include forests in the fight against climate change through a UN mechanism called Reducing Emissions from Deforestation and Forest Degradation.

Known as REDD+, it aims to secure financial and technical support to help curb deforestation in the rainforests of the Democratic Republic of Congo, Indonesia, Brazil and Guatemala.

It also includes a role for conservation, sustainable management of forests and enhancement of forest carbon stocks.

Deforestation, which releases large quantities of CO2 when forests are destroyed, represents around 17 percent of greenhouse gas emissions that causes global warming, more than the total global emissions from transport.

The issue is particularly acute in the Amazon, the world's largest tropical rainforest, dubbed the lungs of the Earth.

Protected areas of the Amazon in Brazil cover more than 2.1 million square kilometers (814,000 square miles) and the government's environmental protection agency IBAMA is playing a key role in deterring deforestation.

An environmental crimes law passed in 1998 gave IBAMA new enforcement powers, which it has used, albeit selectively according to environmentalists, in raids aimed at arresting and fining the most blatant violators of the law.

And experts believe that 40 to 60 percent of the timber extracted from the Amazon is illegal, compared with more than 80 percent 10 years ago.

In 2009, Amazon lumber represented a $2.5 billion market, according to a study by the Imazon institute and the Brazilian forestry agency.

But Durban made only modest headway on REDD+, opening the way to a future carbon market and stressing the need for rules to guarantee emission curbs and protect indigenous communuties and biodiversity.

"We do not have progress on the 'politics behind the money' and without this we cannot talk about sustainability of REDD," said Louis Verchot, a scientist at the Indonesia-based Center for International Forestry Research (CIFOR).

"REDD was overshadowed in Durban by larger issues," said Bruce Cabarle, head of WWF's Climate and Forests initiative.

"All of the global analyses show that we have to have reductions in emissions from the forests fairly soon or else we cannot meet the 2050 goal of keeping (climate-temperatures) increasing more than 2 degrees Celsius."

"For our countries with wide forest coverage, REDD is critical. This requires technical support and resources which is a global responsibility which we have not seen," Maria Fernanda Espinosa, Ecuador's Cultural Patrimony Minister, told AFP.

Deforestation destroys more than seven million hectares (17.2 million acres) every year in the world's main forests where more than one billion people live.

As scientists slammed increasing deforestation rates in Africa, Rachel Kyte, vice president of the Sustainable Development Network at the World Bank, said: "Forests cannot be sustained if people are hungry."

"By far the countries where action on deforestation is required are Brazil and Indonesia," Verchot told AFP. "Together these countries account for more than 70 percent of the deforestation emissions."

But he also stressed the need for progress in the Congo Basin as well as in Malaysia and Myanmar.

In Latin America, Verchot cited some progress in Central America, but said more was needed there as well as in Venezuela, Peru and Bolivia.