Australia's arid heartlands are famed worldwide for their dramatic red sands and Uluru rock but the area is sparsely populated due to the harsh living conditions.
The outback makes up some 70% of the country but due to the desert temperatures 85% of Australians live no more than 50 kilometres from the coast, according to 2016 statistics.
Could technology help at least partially re-green that hot, dry central region, environmentalists have long wondered.
After all, Australian people and animals alike are threatened by increasingly catastrophic environmental events, from droughts, devastating fires and record temperatures to floods. The country suffered particularly devastating bushfires in the 2019 summer season.
AirSeed, a new Australian company, now plans to plant millions of trees by 2024. The firm plans to drop the seeds from the air, onto places where vegetation has been destroyed by fires and clearing.
The company worked with ecologists to create planting patterns and make seed and nutrient capsules that drones drop in the area selected.
"AirSeed's core mission is to restore lost biodiversity at scale by planting native species of trees, shrubs and grasses that are beneficial to a local ecosystem," boss Andrew Walker told dpa.
Drones are promising as they can reach the most remote areas. "Our solution is approximately 25 times faster and 80% more cost effective than manual planting methods," Walker says.
AirSeed has already planted 150,000 trees using this method, it says, with hundreds of thousands more set to follow in the months ahead.
Reforest Now is also committed to reforestation, though the organization isn't focused on the outback. Instead it hopes to grow trees in parts of the rainforest in the tropical north and subtropical northeast of the country.
"We do this not because it is easy but because we live on the driest continent on Earth and it is in desperate need of reforestation," Reforest Now says on its website.
Greening Australia, a nonprofit founded 40 years ago, takes an even broader approach, with projects to restore destroyed habitats in the outback, protect the Great Barrier Reef and green cities. The organization is pursuing a vision of "healthy and productive landscapes where people and nature thrive."
Seeds are in focus here, too, with the team seeking to set up a national network of seed collectors while looking for new ways to produce native seeds.
But the nation's climatic conditions are challenging and unpredictable. "Australia is a dry continent. It has rainfall that comes in large amounts but in unpredictable times," says Glenda Wardle, professor of ecology and evolution at the University of Sydney.
"We have many years of dry and then a lot of rain – goes from poor conditions for production and then suddenly opportunity where it's greening up."
Wardle leads a research group on desert ecology and has doubts about how far arid and semi-arid outback areas can be re-greened. "It is probably a misguided thought that you can artificially green Australia," she says.
"Yes, there is rain water and yes there is ground water, but it's all finite. To keep a desert green you would need a constant supply and there would not be that constant supply."
Still, it's a good idea "to plant back with similar the mixes and densities," she says.
However, foresting is not always the right solution. "We don't want to make forests where they shouldn’t be," Wardle says. Rather, care must be taken to ensure that no other regions are deforested or otherwise modified.
Bush Heritage Australia is dedicated to preserving threatened lands, founded by Greens politician Bob Brown to buy and preserve ecosystems that are particularly endangered. Since its founding in 1991, 39 reserves covering 1.2 million hectares have already been acquired.
The group also works with indigenous and other landowners to help protect millions more acres of land.
"We have some national parks and nature reserves, but still too many landscapes that are not protected at all or not protected enough," says ecologist Anke Frank.
She lives and works on the 233,000-hectare Pilungah Reserve in the Simpson Desert in Queensland, a protected area that traditionally belongs to the Wangkamadla Aborigines.
Here, the circular spinifex grasses common in arid regions are protected, she says, adding that the grass provides a lot of protection itself.
"It's very prickly, and predators have a problem trapping animals under it." But if there is too much forestation, the grass will be trampled and destroyed by livestock, for example.
Frank says what is needed is balance, as reforestation in the wrong place can upset or even destroy an ecosystem.