THE discovery of millions of hectares of unreported forests in some of the world’s driest regions will lead to more accurate global carbon modelling, researchers say.
About 467 million hectares of forest were found in 11 different regions across the world, increasing the current estimate of global forest cover by 10 per cent.
The finding also creates opportunities for improved climate change mitigation strategies through improved conservation and restoration in dryland habitats.
Led by the Food and Agriculture Organisation of the United Nations (FAO), the international study included researchers from the University of Adelaide in South Australia and was published today in Science.
Oceania project lead and Associate Professor at the University of Adelaide Ben Sparrow said the study would prove to be “of high importance in a time of great environmental change”.
“All the modelling on global carbon budgets and what is happening with the environment has largely assumed that drylands are largely grasslands,” he said.
“It is surprising that there is so much dryland forestation and that changes how you calculate the amount of carbon in those environments.
“This won’t just help people create more accurate mitigation schemes but construct different types of schemes that could be more effective.”
A new photo-interpretation tool developed at FAO, called Collect Earth, overcomes the limitations of automatic and often inaccurate categorisation of forest types of satellite imagery by using a simple validation check for tree number and density.
Data supplied by the Terrestrial Ecosystem Research Network (TERN) at the University of Adelaide was crucial in providing the on-ground verification of the project.
The TERN AUSplots field data was the only global plot-based data source readily available and accurate enough to assess observer accuracy for the project.
The research teams analysed very high-resolution satellite imagery of more than 210,000 dryland monitoring sites to calculate global forest cover and its change over time.
Associate Professor Sparrow said the finding was significant because it incorporated a broad data set that included unique vegetation such as Australia’s eucalyptus and acacia trees.
The study identified dryland forests across all inhabited continents, and concentrated to the south of the Sahara desert, around the Mediterranean, southern Africa, central India, coastal Australia, western South America, north-east Brazil, northern Colombia and Venezuela, and northern parts of the boreal forests in Canada and Russia.
Chair of Plant Conservation Biology at the University of Adelaide Andrew Lowe said finding an area of forest that represented 10 per cent of global cover could lead to improved livelihoods for people in those areas.
"Just when we thought we knew the world, this project shows we are still improving our knowledge and description of natural systems,” he said.
“It shows that dryland regions have a greater capacity to support trees than previously perceived and understood.
“With its low opportunity costs, dryland could therefore provide a unique chance to mitigate climate change through large-scale conservation and afforestation actions.”
South Australia’s capital Adelaide has three long-standing public universities, Flinders University, University of South Australia and the University of Adelaide, each of which are consistently rated highly in the international higher education rankings.