A new global analysis of the distribution of forests and woodlands has “found” 467 million hectares of previously unreported forest – an area equivalent to 60% of the size of Australia. 
 
 The discovery increases the known amount of global forest cover by around 9%, and will significantly boost estimates of how much carbon is stored in plants worldwide. 
 
 The new forests were found by surveying “drylands” – so called because they receive much less water in precipitation than they lose through evaporation and plant transpiration. As we and our colleagues report today in the journal Science, these drylands contain 45% more forest than has been found in previous surveys. 
 
 We found new dryland forest on all inhabited continents, but mainly in sub-Saharan Africa, around the Mediterranean, central India, coastal Australia, western South America, northeastern Brazil, northern Colombia and Venezuela, and northern parts of the boreal forests in Canada and Russia. In Africa, our study has doubled the amount of known dryland forest. 
 
 With current satellite imagery and mapping techniques, it might seem amazing that these forests have stayed hidden in plain sight for so long. But this type of forest was previously difficult to measure globally, because of the relatively low density of trees. 
 
 What’s more, previous surveys were based on older, low-resolution satellite images that did not include ground validation. In contrast, our study used higher-resolution satellite imagery available through Google Earth Engine – including images of more than 210,000 dryland sites – and used a simple visual interpretation of tree number and density. A sample of these sites were compared with field information to assess accuracy. 
 
 Unique opportunity 
 
 Given that drylands – which make up about 40% of Earth’s land surface – have more capacity to support trees and forest than we previously realised, we have a unique chance to combat climate change by conserving these previously unappreciated forests. 
 
 Drylands contain some of the most threatened, yet disregarded, ecosystems, many of which face pressure from climate change and human activity. Climate change will cause many of these regions to become hotter and even drier, while human expansion could degrade these landscapes yet further. Climate models suggest that dryland biomes could expand by 11-23% by the end of the this century, meaning they could cover more than half of Earth’s land surface. 
 
 Considering the potential of dryland forests to stave off desertification and to fight climate change by storing carbon, it will be crucial to keep monitoring the health of these forests, now that we know they are there. 
 
 TERN AusPlots , Author provided 
 
 Climate policy boost 
 
 The discovery will dramatically improve the accuracy of models used to calculate how much carbon is stored in Earth’s landscapes. This in turn will help calculate the carbon budgets by which countries can measure their progress towards the targets set out in the Kyoto Protocol and its successor, the Paris Agreement. 
 
 Our study increases the estimates of total global forest carbon stocks by anywhere between 15 gigatonnes and 158 gigatonnes of carbon – an increase of between 2% and 20%. 
 
 This study provides more accurate baseline information on the current status of carbon sinks, on which future carbon and climate modelling can be based. This will reduce errors for modelling of dryland regions worldwide. Our discovery also highlights the importance of conservation and forest growth in these areas. 
 
 The authors acknowledge the input of Jean-François Bastin and Mark Grant in the writing of this article. The research was carried out by researchers from 14 organisations around the world, as part of the UN Food and Agriculture Organization’s Global Forest Survey. ||||| Forests equal to 60pc of Australian landmass discovered using new tool 
 
 Posted 
 
 Vast stretches of previously undocumented forest have been discovered using a new tool to analyse the surface of the Earth. 
 
 International researchers have discovered 467 million hectares, an area equivalent to 60 per cent of the size of Australia, of what was previously considered dry land is actually dense forest. 
 
 The research led by the Food and Agriculture Organisation of the United Nations, teams of scientists and students from 15 organisations, including the University of Adelaide, carried out the analysis using the photo-interpretation tool called Collect Earth. 
 
 University of Adelaide's plant conservation biology chairman Professor Andrew Lowe said the finding meant scientists had a new resource that could help mitigate climate change. 
 
 "In the modern digital age we think we know everything about the Earth, but a lot of that knowledge comes from satellite imagery, like Google Earth," he said. 
 
 "But when you use that type of satellite data you have to make estimations on what type of vegetation occurs on the ground." 
 
 It turns out some of those estimations were wrong and areas across the globe, including along parts of the Australian coast, are full of trees and plants. 
 
 He said if the newly discovered forests are protected, they could provide information about how trees "fix" carbon, and prompt a re-evaluation of the global "carbon budget". 
 
 "We know that forests sequester huge amounts of carbon, so increasing the area of forest globally helps explain additional carbon sequestration opportunities that are available," Professor Lowe said. 
 
 The study identified dryland forest across all inhabited continents, and concentrated to the south of the Sahara desert, around the Mediterranean, south 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. 
 
 The paper published today in the journal Science states the differences in coverage were most significant in Africa, where the estimates have doubled. 
 
 Topics: science-and-technology, earth-sciences, environment, environmental-impact, environment-education, education, environmental-technology, research, adelaide-university-5005, sa ||||| A new estimate of dryland forests suggests that the global forest cover is at least 9% higher than previously thought. The finding will help reduce uncertainties surrounding terrestrial carbon sink estimates. 
 
 Dryland biomes, where precipitation is more than counterbalanced by evaporation from surfaces and transpiration by plants, cover about 40% of the Earth's land surface. 
 
 These biomes contain some of the most threatened ecosystems, including biodiversity hotspots. However, previous estimates of dryland forests have been riddled with disparities, caused by issues such as differences in satellite spatial resolution, mapping approaches and forest definitions. 
 
 These disparities have led to major doubts about the reliability of global forest area estimates, and to questions about the real contribution made by forests to the global carbon cycle. Here, Jean-Francois Bastin et al. analyzed satellite data from Google Earth, using a detail sample pool of 213,795 0.5 hectare plots from around the globe. 
 
 Their new estimate of dryland forest is 40 to 47% higher than previous estimates, corresponding to 467 million hectares (Mha) of forest that have never been reported before. 
 
 This increases current estimates of global forest cover by at least 9%. These results explain the difference between recent global estimates of forest "land use" area (3890 Mha) and the area with a "land cover," the authors say. ||||| Thank you for your interest in spreading the word about Science. 
 
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– Scientists have discovered 467 million hectares of unreported forest—about three-fifths the size of Australia—scattered around the globe, the Conversation reports. The discovery increases the known global forest cover by about 9%. The study—published Friday in Science—focused on "drylands," areas that lose more water through evaporation and plant transpiration than they receive in precipitation. Trees in drylands aren't very dense, which can make it difficult to measure possible forest cover. According to a press release, old estimates of dryland forests were off due to a number of factors, including low image resolution from satellites and the methods of mapping used. The new study used high-resolution images of more than 210,000 dryland sites from Google Earth Engine and combined them with observations on the ground. Researchers found between 40% to 47% more forest cover in the world's drylands than previously reported. New forests were found on all continents—besides Antarctica. ABC reports the research, led by the Food and Agriculture Organization of the United Nations, gives a new tool in the fight against climate change; it boosts estimates of the amount of carbon stored in plants globally. (New database gives tree scientists an important first.)