Two major UN conferences on climate change and sustainable development must tackle the key issue of deforestation, the World Forestry Congress urged Friday.

"Forests are an essential solution to climate change adaptation and mitigation," according to a statement released by the congress, which drew 4,000 delegates from government, conservation groups and the private sector to the South African city of  this week.

Apart from offering oxygen, fuel and building material, trees store important quantities of carbon gas, which, if released, contribute to global warming.

Members of the UN Framework Convention on Climate Change (UNFCCC) are due to meet in Paris from November 30 to December 11, bidding for a landmark agreement to curb carbon emissions.

"Climate change poses a serious threat to the planet and to forests and forest-dependent people, and there is a risk that actions will fall short of what is required," the congress said.

The Durban meeting also targeted the UN General Assembly summit in New York later this month on adopting the 2030 Agenda for Sustainable Development.

A UN report released at the congress on Monday noted that although some progress has been made in slowing the rate of forest destruction, an area of woodland the size of South Africa has been lost since 1990.

The international conservation organisation WWF hailed the congress's declaration.

"As we head into the UN climate change talks in Paris, all parties need to make sure the new climate deal creates incentives for the actions needed to reduce forest loss," it said.