Danger to Earth lungs

Members of the Awa Tribe in the Para province of the Brazilian Amazon Jungle walk along a path cleared by loggers. Photo / Supplied

About half the 15,000 tree species in the Amazon - the world's most diverse forest - are threatened by deforestation, an international study says.

The report lays bare the destruction of an ecosystem often referred to as the lungs of the Earth.

"At least 36 per cent and up to 57 per cent of all Amazonian tree species are likely to qualify as globally threatened," said the study in the journal Science Advances, which used criteria from the respected International Union for Conservation of Nature (IUCN).

Under a business-as-usual scenario, about 40 per cent of the original Amazon forest would be destroyed by 2050, the researchers found. But with stricter conservation measures, they said, that number could be halved.

The good news is that significant populations of endangered trees survive in protected areas of the Amazon, the researchers said.

Still, they added, only constant vigilance over valuable trees like the Brazil nut - 63 per cent of which could otherwise be lost by 2050 - will help preserve the Amazon's status as a major carbon sink.

The cacao tree could decline by 50 per cent within 35 years under a business-as-usual scenario and the acai palm could decline 72 per cent. Already, the prized mahogany tree is considered commercially extinct.

The report was based on forest surveys across the Amazon and maps of current and projected deforestation. Researchers from 21 countries contributed.

"Either we stand up and protect these critical parks and indigenous reserves, or deforestation will erode them until we see large-scale extinctions," said lead author Hans ter Steege of Naturalis Biodiversity Centre in the Netherlands.

- AAP