A study led by Yale University researchers has found that there are over 3 trillion trees on Earth - but they are disappearing at an alarming rate.

The study found that there are around 3.04 trillion trees on Earth, or around 422 for each person on the planet.

The number is a huge increase on the previous global estimate, which was just over 400 billion trees worldwide.

The study was based on on-the-ground data about the number of trees in more than 400,000 plots of forest from all continents except Antarctica.

Wildlife Photographer of the Year 2015 Show all 9 1 /9 Wildlife Photographer of the Year 2015 Wildlife Photographer of the Year 2015 'To Drink or Not' - Carlos Perez Naval, Spain, 10 Years and Under Carlos was down on the beach at Morro Bay in California, on holiday with his family, when he witnessed a fascinating interaction between two different species. A colony of California ground squirrels lives among the rocks at one side of the bay, fed by locals, who also put out dishes of water for them. What Carlos noticed was that western gulls were monopolizing the water. Whenever a ground squirrel dared to get too close, a gull would chase it away, aiming its powerful beak at the squirrel’s head. Carlos was fascinated by the way the ground squirrels would try to sneak in for a sip when the gulls weren’t looking. Here, the two competitors’ eyes lock over the coveted fresh water. Carlos took the shot just before the gull lunged forwards and the squirrel fled. Carlos Perez Naval Wildlife Photographer of the Year 2015 'Snow Hare' - Rosamund Macfarlane, UK, Mammals One of Rosamund’s photographic ambitions was to photograph Scottish mountain hares in the snow, camouflaged in their winter coats. Native to Britain, mountain hares moult from brown to white or partially white in winter, depending on temperature. With a local expert, Rosamund climbed a valley in the Scottish Cairngorms, ‘at times through knee-deep snow’, until they came across a couple of hares that allowed them to approach within photographic range. Their mottled, snow-dusted coats echoed the colours of the snow-covered hillside. For several hours, Rosamund lay on the ground in freezing temperatures, observing the hares snuggled into their forms (shallow depressions) as fine snow blew over them and rime coated their pelts. In the late afternoon, the hares finally became active and started to feed, scraping the snow from the heather and then nibbling the shoots. Positioning herself so that she was looking up a gentle incline directly at one hare, Rosamund captured its determined scrabbling in a head-on portrait. Rosamund Macfarlane Wildlife Photographer of the Year 2015 'Great Egret Awakening' - Zsolt Kudich, Hungary, Birds When the River Danube flooded into Hungary’s Gemenc Forest, more than a thousand great egrets flocked to the lake to feed on the stranded amphibians, fish and invertebrates. Working on a project to document the last untouched regions of the Danube, including the floodplains, Zsolt was delighted to find a sixth of Hungary’s great egret population in the one place. By 1921, hunting had reduced their number to just 31 pairs. Today, habitat loss is the big threat. Using the soft dawn light, Zsolt wanted to convey the impression of a multitude of birds. So he pitched his camouflaged tent nearby, sleeping just a few hours a night for five nights. His chance came when a fishing white-tailed eagle sent some of the egrets into the air. With a slow shutter speed to blur the wings and a large depth of field to keep in focus those standing, Zsolt got his memorable image. Zsolt Kudich Wildlife Photographer of the Year 2015 'Komodo Judo' - Andrey Gudkov, Russia, Amphibians & Reptiles The fight was fast and unexpected. Andrey had been to Indonesia’s Komodo National Park, many times before, hoping to witness a battle between male Komodo dragons – the largest lizards in the world, up to 2.5 metres (8 feet) long. And though he had visited in August, when males are most likely to battle over females, he had never been lucky. But on this December morning, on Rinca Island, he had found two large males hissing angrily at each other. To his surprise, the confrontation escalated. The lizards reared up on their hind legs, supported by their long, muscular tails, and suddenly everything came together: two formidable dragons ‘dancing the tango’ at the crest of a hill against a beautiful backdrop, without the usual tall grass obscuring the action. Andrey seized his chance, knowing that Komodo dragons can move fast and that their bites are venomous, secreting a mix of toxic substances from glands in their jaws into the wounds made by their teeth. The dragons fought two consecutive bouts of a few seconds each until one overpowered the other, knocking him over backwards, and the pair walked off in different directions. With quick reactions and a fast shutter speed, Andrey had nailed the shot he had dreamt of. Andrey Gudkov Wildlife Photographer of the Year 2015 'It Came From the Deep' - Fabien Michenet, France, Underwater Fabien spends many hours diving at night in deep water off the coast of Tahiti, French Polynesia, where he lives. He is fascinated by the diversity of tiny creatures that migrate up from the depths under cover of darkness. These zooplankton feed on the phytoplankton found near the surface (which need sunlight to photosynthesize) and are themselves hunted by small predators that follow their ascent. One night, about 20 metres (66 feet) below the surface, in water 1,000 metres (3,300 feet) deep, some juvenile octopuses – just 2 centimetres (an inch) across, swam into view. ‘One of them stopped in front me,’ says Fabien, ‘waving its tentacles gracefully, perhaps taking advantage of my lights to hunt the little crustaceans that were swimming around.’ Its body was transparent – camouflage for the open ocean – revealing its internal organs. Chromatophores (colour‐changing cells) were visible on its tentacles, possibly for use in the light, when a different kind of camouflage would be needed. By keeping as close as possible and drifting at exactly the same speed as the diminutive octopus, and taking care not to upset its natural behaviour with strong lighting, Fabien was able to capture his eye-to-eye portrait. Fabien Michenet Wildlife Photographer of the Year 2015 'Jagged Peace' - Floris van Breugel, USA, Land ‘It was a rare opportunity,’ says Floris, grateful to his companion, who was skilled at predicting weather patterns in this part of Patagonia. ‘There was enough snow to stick to the trees but not so much as to make travel dangerous, no wind, an unfrozen lake and a clear view of Fitz Roy.’ They had waited out a snowstorm before donning snowshoes and heading into the backcountry of Argentina’s Los Glaciares National Park. A designated World Heritage Site, the park boasts the largest ice mantle outside Antarctica, with numerous glaciers, lakes and towering mountains. Mount Fitz Roy – also known as the ‘smoking mountain’, after the cloud that usually forms around its peak – is the highest, rising a jagged 3,375 metres (11,000 feet) above sea level. While Floris was scouting for compositions, a little bird showed up – a black-billed shrike-tyrant (named after the aggressive nature of some species in its tyrant flycatcher family). With fresh snow and muted light evoking the quiet wilderness, the bird completed the shot, adding a sense of scale and connection to the landscape. Floris van Breugel Wildlife Photographer of the Year 2015 'Stork Art' - Francisco Mingorance, Spain, Urban Wildlife White storks seem equally at home on artificial structures as they are in trees, often nesting on rooftops and telegraph poles. Francisco discovered three pairs high on this sculpture outside the Vostell-Malpartida Museum near Cáceres in Spain. The installation, by German artist Wolf Vostell, incorporates a Russian MiG-21 aircraft, two cars, pianos, computer monitors – and now, three huge nests, which the storks use each year, migrating from their overwintering grounds in southern Africa. Francisco wanted a picture of the storks sleeping under a starry sky, but there was too much light. ‘I got special permission for most lights to be shut down,’ he says, ‘but then the storks kept moving about and flying off.’ Using a long exposure, he got just one shot he liked, with the storks quietly asserting their place in the modern world that Vostell depicted. Francisco Mingorance Wildlife Photographer of the Year 2015 'Natural Frame' - Morkel Erasmus, South Africa, Black & White Morkel could hear every rumble. He could even smell the elephants. But his view was limited to the viewing slit of a cramped bunker sunk into the ground beside a remote waterhole in Namibia’s Etosha National Park. Giraffes, zebras and kudu wandered in and out of view, but the elephants were right in front, sometimes so close that his view was blocked. Morkel used black and white to place the emphasis on the composition. His moment came when a mother framed his shot with her legs just as her calf walked into view framing a giraffe. Having caught his ‘dream moment’, Morkel put down his camera and just sat and enjoyed the ‘bliss’ of watching wild animals taking their turn to drink from this life-giving waterhole. Morkel Erasmus Wildlife Photographer of the Year 2015 'Gorilla Care' - Marcus Westberg, Sweden, Photojournalism Award: Single Image Ndeze, a nine-year-old orphan mountain gorilla, watches with concern as veterinarians check the health of her female companion, twelve-year-old Maisha, in the Senkwekwe Centre at the headquarters of the Virunga National Park, in the Democratic Republic of the Congo. The resident ‘gorilla doctor’ Eddy Kambale (here with the former regional director Jan Ramer, left, assisted by two visiting vets) runs thorough health checks every year on the four orphan mountain gorillas, all of whom have been rescued from poachers and traffickers and have suffered traumatic experiences. The centre – named after Ndeze’s father, who was murdered along with Ndeze’s mother and several other members of her family in 2007 – is just part of the park’s efforts to protect the surviving mountain gorillas. ‘The deep bonds that exist between these orphans, their carers and Eddy is one of the most touching things I have ever had the privilege of witnessing,’ says Marcus. Marcus Westberg

Researchers then used satellite imagery and assessed how the data was related to local factors like climate, human activity and soil conditions, and used the information to build a global model.

Despite this seemingly huge number, trees are disappearing fast. Around 15 billion are lost every year due to deforestation, forest management and changes in land use, the research published in the journal Nature found.

Overall, humanity has been bad for trees - the study found that since the start of human civilisation, around 11,700 years ago, the total number of trees has fallen by around 46 per cent.

Although coming up with an accurate estimate of the number of trees is an impressive feat, it also has practical applications - helping other researchers and scientists more accurately study the changing climate and the distribution of animal and plant species.

Thomas Crowther, the lead author of the study and the a post-doctoral fellow at the Yale School of Forestry and Environmental Studies, said: "Trees are among the most prominent and critical organisms on Earth, yet we are only recently beginning to comprehend their global extent and distribution."

"They store huge amounts of carbon, are essential for the cycling of nutrients, for water and air quality, and for countless human services."

Workers clear forest in Indonesia with heavy machinery. Around 15 billion trees are lost every year. (BAY ISMOYO/AFP/Getty Images)

"Yet you ask people to estimate, within an order of magnitude, how many trees there are and they don't know where to begin," he said, adding he was "certainly surprised" to find the estimate was in the trillions.

He said: "We've nearly halved the number of trees on the planet, and we've seen the impacts on climate and human health as a result."

"This study highlights how much more effort is needed if we are to restore healthy forests worldwide."

There are around three billion trees in the UK, or around 47 for every Briton.