30 August, 2017
Can swarms of seed-bearing drones help regrow the planet's forests?
At the moment, the planet loses about six billion trees each year. Seed-planting drones may represent the most futuristic way to re-establish tree cover on a large scale.
Wildfires, desertification and mud slides are terrifying results of increasing deforestation. Can swarms of seed-planting drones reverse the deadly slide?
Resting in the middle of a grassy field like a giant black beetle, the multi-rotor drone looks pretty much like any other commercial model - the type you might see hovering over a football stadium, capturing bird's-eye footage of a forward charging towards the try line. Similar helicopter-like drones, equipped with cameras and sensors, are set to take to our skies in droves over the next decade: in the US, companies such as Amazon, Domino's, Walmart and Google are trialling drone delivery systems; in Australia they're already being used by industries as diverse as real estate and defence, and are currently being tested for their ability to deliver vital medical supplies to remote areas.
But once this remote-control drone takes off from its grassy resting spot in rural NSW, it behaves very differently from its quadcopter cousins. Instead of soaring skywards, it hovers just one to two metres off the ground, firing 150 bullet-shaped pods of germinated seeds into the soil below at high speed - ffwat, ffwat, ffwat - almost like a machine gun. With two operators running six or seven of these drones at a time, an astonishing 36,000 seeds can be planted in a day: 10 times the speed of hand planting, and at a fraction of the cost. Just imagine what swarms of these machines - think hundreds of them - could achieve, replanting trees across vast areas devastated by logging or bushfires.
For Australian engineer Dr Susan Graham, who helped develop this unmanned aerial vehicle with retired NASA engineer Lauren Fletcher, the only way to combat industrial-scale deforestation across the globe is with industrial-scale reforestation. Graham credits Fletcher, CEO of the UK-based start-up drone company BioCarbon Engineering, with developing the original idea more than two years ago. "Lauren was able to draw the dots between increasing deforestation and the emerging technologies of robotics, remote sensing and artificial intelligence," she says. With 100 two-member teams, BioCarbon, which has the backing of drone company VulcanUAV, has set an ambitious target of planting more than a billion trees in the next five to seven years.
Formerly of the University of Sydney and now with the department of engineering science at Oxford University, Graham presented the drone technology at a United Nations summit in late 2015. First, a mapping drone takes a 3D aerial survey of the terrain, highlighting existing vegetation and biodiversity, information that is used to pinpoint the best planting pattern (local people, too, are consulted as to what type of trees thrive or fail in the area). The map is uploaded into the quadcopter planting drone, equipped with its pressurised canisters of pods, each containing a germinated seed immersed in a nutrient-rich gel. The pods break open upon impact with the soil, allowing the germinated seeds to take root in the predetermined positions.
The multi-faceted mapping system determines the selection of seeds, as the system is designed to restore diverse ecosystems rather than plantations of the same trees, says Graham. Tree growth is subsequently monitored by other drones, which can supply information to locals on fertilisers, nutrients and pest control.
Although fixed-wing drones are already being used by Australia's forestry industry to measure tree density and regeneration after bushfires, tree-planting propeller drones represent a new and dramatic way to reforest areas destroyed by mining, logging or desertification. BioCarbon is already working with companies, non-government organisations and landholders to finesse its technology, including experiments with seed varieties within greenhouses in the UK and mapping tests in South Africa and Australia.
We're in a race against time. The planet lost 1.3-million square kilometres of forests between 1990 and 2015 - an area larger than South Africa or Peru, according to the World Bank. More than half of Indonesia's rainforest is now gone, bulldozed for palm oil plantations, logging and pulp, and the tree-felling is accelerating thanks to rampant corruption and political cronyism. At least one million hectares are levelled there each year, with burn-offs pushing palls of noxious smoke across Singapore and Malaysia. In 2012, Indonesia eclipsed Brazil in having the highest rate of deforestation in the world; a walloping 85 per cent of its carbon emissions stem from rainforest and peat land degradation, according to Naturemagazine.
Very poor countries like Haiti and Myanmar, which have less than half of their tree canopy remaining, are facing ecological time bombs if the clear-cutting continues. Nor does a wealthy country like Australia have anything to be proud of: since white settlement we've wiped out 40 per cent of our forests, by a WWF Australia estimate. Most worrying, deforestation is on an up-tick in NSW and Queensland, where almost 20 million trees are felled each year - an unfolding calamity, according to the Rainforest Trust. (WWF Australia says that koala numbers on the Koala Coast, south-east of Brisbane, are down 80 per cent on 20 years ago.) Last year, at the Society for Conservation Biology Oceania conference in Brisbane, more than 200 senior scientists signed a statement warning of the unbridled deforestation taking place across the continent.
"Globally, we currently lose about 15 billion trees each year, and replant about 9 billion - a loss of six billion annually," notes Graham. Drones can help scale regrowth well beyond current capacity, she adds, as part of a suite of measures to combat deforestation. She hypothesises that if we grew 500 billion trees - the equivalent of planting another Amazon (which contains about 400 billion trees) - we could offset all human carbon emissions.
The amount of arable land has also dropped precipitously - at least 30 per cent over the past 40 years, thanks to erosion and pollution - while we'll need 50 per cent more food to feed an anticipated global population of 9 billion people by 2050. Trees knit soil together, promote soil fertility, breathe out oxygen and, vitally, in the age of climate change, vacuum up carbon dioxide to store in their trunks and branches. Deforestation made up 18 per cent of global carbon emissions in 2013 - more than the world's entire transportation system - according to the Climate Council of Australia.
The frightening cost of this forest loss is now playing out across the globe, from this year's mud slides in Sierra Leone and Sri Lanka to wildfires across the western US, British Columbia, central Portugal, southern Italy, Chile and, most recently, Siberia. (Projections by the Union of Concerned Scientists suggest that wildfires could become four, five and even six times as severe as they are now by 2100.)
It's a depressing tableau, and a cry of pain for endangered species, such as the orangutan, African elephant and bonobo, holding on for dear life in fast-dwindling habitats.
Grant Canary, CEO of DroneSeed in the US - the only company besides BioCarbon working with seed-depositing drones - insists that drones are a superior vehicle for planting, especially in forests damaged by wildfires and in rugged, steep hillsides that are hard to reach for manual planters. "Multi-rotor craft can hover, allowing them to identify and fire seeds into the ground in places - microsites - they will grow well," he says. "Hitting these microsites is not possible from a plane and very hard from a helicopter."
DroneSeed CEO Grant Canary, with drone.
For the moment, DroneSeed is concentrating on spraying to control fungi and pests, for which it received approval from the US Food and Drug Administration in May. "This will help our saplings thrive in the future," Canary explains. "Planting without spraying is like having a garden without weeding it. Results will be sporadic and likely poor." DroneSeed says each of its drones can plant 800 seeds per hour (at one-tenth of the cost of human labour) and the company is currently working with the forestry industry and National Park Service in the US. "Our first clients are timber companies, which use very carefully bred seeds from seed orchards."
The litmus test will be how many saplings spring from the seed bombing - and how many survive to become mature trees. "We've been stress-testing our system in many different environments," says Graham. One of the areas in which seed bombing could prove especially successful is restoring tree cover in the moonscape of former mining sites, she adds. While BioCarbon Engineering is focusing its research and replant efforts in Europe and developing countries, with an eye on South Africa and Brazil, DroneSeed is concentrating on the Pacific Northwest, in the likes of Washington State and British Columbia. On the academic front, researchers at the Indian Institute of Science in Bangalore launched a droneseeding trial in June this year.
While seed-planting drones may represent the most futuristic way to re-establish tree cover on a large scale, other backto-basics approaches, born of decades of working with the populations of very poor African countries, have reaped highly encouraging results. When deforestation runs rampant for a long period, the soil that remains becomes so tightly compressed that it can hardly hold water to let roots spread. In environments like this, the germination rate from drones, dispersing even the hardiest of seeds, might prove disappointingly low. And here's the thing: Africa's population has increased fivefold since the 1950s, which has exhausted much of the continent's farming land.
But if there is a greater sense of optimism across parts of the continent these days, it's at least partly due to the Australian Tony Rinaudo, who helped pioneer Farmer Managed Natural Regeneration (FMNR), a technique that helps poor subsistence farmers restore the landscape - and their livelihood. The technique has resulted in the regrowth of an astonishing 200 million trees across Niger alone since the 1980s.
Rinaudo, who has worked for the Christian-based non-government organisation World Vision for the past 18 years and is based in Melbourne, helped bring the world's attention to the existence of so-called underground forests. Just beneath what may appear to be cleared wastelands are stumps, roots and seeds bristling with the potential to regenerate, but constantly hobbled by overgrazing.
When Rinaudo landed in Niger in 1980, as a 23-year-old missionary from the Myrtleford Uniting Church in Victoria and part of a Canadian-funded reforestation project, he was horrified by what he saw. Large swaths of once-healthy forest in the west African nation's Maradi region had dissolved into a parched hellscape thanks to decades of slash-and-burn tree-felling, continuous ploughing and overgrazing. Women were bent over double, hoeing scrawny plants in dirt dried hard from the unforgiving sun.
"They were walking kilometres for a miserable bundle of sticks to light a fire," he recalls. "The indigenous vegetation that had once been their supermarket, medicine chest and hardware store was largely gone, smothered in sand."
At first, Rinaudo tried the conventional method of restoring the land, carefully nurturing saplings in village nurseries and planting them on a large scale to create windbreaks and wood lots. But the vast majority perished in the harsh conditions within a year or two. "It was devastating," he sighs. "These people had become my friends and it was terrible seeing them suffer."
Rinaudo was on the point of giving up on the reforestation project when, one hot day in 1983, he noticed an assortment of small shrubs studding the arid landscape. He'd earlier dismissed these as weeds, but upon closer inspection realised they were shoots of regrowth from the original forest. That triggered a thunderbolt.
"The solution was literally at our feet," he explains. "Although the landscape looked barren, only 20 or 30 years before it had been dry land forest. The seeds were still in the soil, ready to germinate given the right conditions."
More to the point, the bounty below would grow back quickly if left to lie fallow and not be reduced to stubble with each planting season. "You have 100 per cent survival rate with regenerated trees, compared to 10 to 20 per cent for planted seedlings," he explains. "A seedling is very fragile, while a tree stump is very robust, with metres of roots underground. From a tree stump you can get up to two metres of growth for a year."
The biggest battle was not against the environment but human attitudes. "The locals called me the 'mad white farmer'," he laughs. "Why plant trees on good agricultural land, they kept asking me." Hardest to convince were the poorest subsistence farmers, who saw planting trees as a waste of precious resources and space. "They said that if they didn't cut down a tree, someone else would." Rinaudo was able to mobilise the support of Niger's forestry commission, government authorities and about a dozen local farmers for pilot projects, which began to show benefits within a year or two; within five years, substantial numbers of trees had regrown. As it became obvious that the trees provided windbreaks, boosted soil fertility and water quality, and therefore resulted in healthier crop harvests, word spread to other villages. "It's important to 'hurry slowly', to listen to the local people and not treat them as 'blank slates'," Rinaudo concludes.
As trees grew back, creating shade, soil temperatures began to drop, which made it easier for crops to bloom. "Trees draw moisture from deep in the soil and put nitrogen back," he says. "A much more hospitable living environment was created. When I first arrived, the workers would have to pack up their tools by 10am because it was too hot to work."
Rinaudo spent more than 17 years in Niger and witnessed one of the greatest "green" recovery stories on the planet (surprisingly, it has received only a small amount of publicity), a re-greening by FMNR that spread to neighbouring Mali and Senegal. Now 60, Rinaudo still spends about five months a year overseas - earlier this year he was in Kenya finalising plans for an eight country re-greening project funded by the European Commission - and believes there are low-cost ways of restoring land and tackling climate change.
It was as if it was meant to be. When he was about 14, Rinaudo came across a book sitting among a dusty pile of hardbacks in a friend's backyard shed that would change his life. Man of the Trees was written by Richard St. Barbe Baker, a 20th-century English forester and environmental activist who was one of the first to recognise that the clear-felling of trees results in poorer soil and water quality and a drop in biodiversity. Long before mass deforestation, Baker saw the effects of centuries of land mismanagement in North Africa from wheat farming during the Roman Empire. "I found the book totally inspiring," Rinaudo says simply.
The world's forests are in a much more perilous position than when Rinaudo was a boy in the 1960s. "Just about every country is suffering from land degradation to some degree," he acknowledges. "It's becoming more of a problem in southern Africa than nations closer to the Sahara. A quarter of India's land mass is vulnerable to degradation; East Timor has a massive deforestation problem."
While the world's forest cover continues to shrink, the rate of loss is not as dire as some scientists predicted in the late 1990s, reducing by half over the past 20 years, according to a recent UN report. There have also been significant gains in combating desertification in China and Mongolia. A third of Inner Mongolia's Kubuqi Desert has been greened over the past three decades, with a range of drought-resistant plants chosen to grip the shifting sands and prevent the golden dunes from swallowing up farms and villages. The lessons learnt from Kubuqi have been studied by teams of experts from China, Saudi Arabia and Pakistan.
There has also been China's Three-North Shelterbelt Program - popularly known as the "Great Green Wall" - designed to hold back the rapidly encroaching Gobi Desert, which has engulfed hundreds of kilometres of rolling grasslands and topsoil since the 1960s. More than 66 billion trees have been planted - by aerial seeding, mechanisation and hand - since the project began in 1978 under instructions by the Chinese Government. By the time it's completed in 2050, the Green Wall will be 4500 kilometres long. It's already the largest artificial forest in the world.
But it hasn't been a singular success. Forestry experts have criticised the project for its focus on monoculture poplar plantations (which are vulnerable to disease and don't attract birds and wildlife) and over-planting, which has resulted in a drop of up to 19 metres in groundwater in some areas. Even at the current rate of replanting, it will take an estimated 300 years to reclaim the land that's become desert over the past century. Even that may be optimistic: millions of the planted trees die each year - in 2000, an astonishing one billion trees perished from blight - setting back even the most vigorous of replanting efforts.
Thailand is planning aerial reforestation using seed bombs dropped from planes (packed into biodegradable compounds) but it's unlikely these will have a high success rate because of the elevation of the plane, according to Grant Canary. "Light planes are useful for flat-terrain crop dusting," he says. "They can eliminate vegetation that would grow faster and shade out planted trees." Drone swarms are the most efficient at planting, and are a lot safer and faster than helicopters.
But if we continue to play climate roulette, it's likely many of the gains with planting new forests will fail in the long-term as temperatures become inhospitable. Climate models also predict that deforestation in one area can impact another: tree loss in the Amazon, for example, could affect rainfall in the US Midwest.
Far and away the best strategy to keep the planet green and healthy, the experts agree, is to stop deforestation in the first place and allow denuded areas time to recover. "Some of the world's forests are being allowed to grow back,such as in the US," says Stephen Roxburgh, a research group leader in forest systems with the CSIRO. "New satellite technology is also better able to measure not just the size of forests but the height of trees and therefore how much biomass they contain." But it's impossible to underestimate the importance of old-growth forests, he adds. "The regeneration of a forest to its original state can take centuries."
It may surprise many that the Middle East and North Africa had the largest percentage increase in green cover between 1990 and 2015, albeit from a very low base. In the superparched Middle East, as with anywhere else on the planet, no plant can grow without water. Mega-scale desalination plants are mushrooming across the region - the biggest, Israel's Sorek plant, churns out 627,000 cubic metres of fresh water daily, 40per cent of the country's water supply - in preparation for a drier future.
But Saudi Arabia still holds the crown of the largest producer of desalinated water in the world, with 27 plants at 17 locations. Their output dwarfs that of Australia's biggest desalination plant in Sydney (at 250 megalitres, it provides 15 per cent of the city's water supply).
Desalination capacity in the Gulf region is projected to nearly double between 2012 and 2030. Countries like the UAE and Saudi Arabia use waste water - specifically grey water - to grow crops and spread green cover. One major problem: desal plants devour large amounts of electricity to force seawater through membranes and filters, meaning they can have a large carbon footprint unless generated from solar or wind power. And the super salty discharge is pumped back into the Gulf, creating challenges for its ecosystems.
Cities also need trees - urban forests in the form of parks, rooftop and vertical gardens - as mega cities like Shanghai, São Paulo, Jakarta and Mumbai stretch their concrete tentacles over hundreds of square kilometres. During heavy storms, trees and their surrounding soil absorb a great deal of rainwater, decreasing the burden on sewer systems and preventing flooding.
Trees also act as natural air conditioners, dispersing air moisture that keep cities cooler during heatwaves, and helping to offset the urban heat island effect, created by factors including bitumen and cement radiating stored heat. Last March, officials in Hebei Province, which surrounds Beijing, announced a plan to create a "green necklace" of trees around the city in the hope of cleaning up the city's thick smog, which is among the worst in the world.
"There is mounting evidence that tree cover in cities influences local weather patterns, reducing excessive heat and dryness," says Simon Toze, a principal researcher with the CSIRO and an expert in the urban heat island effect. "Green cover moderates temperatures, reduces wind tunnels and improves air quality. If you get the right sort of plants, they can aid with cooling and warming your building. And improve your well-being, as well.
We don't need a mountain of studies to confirm that green spaces are vital for human health. Measuring the worth of a forest in terms of the crude price of timber or the short-term yield from a palm plantation is a poor business model. It doesn't quantify the forest's ability to prevent soil erosion, provide clean air and fresh water, sequester carbon, provide any number of medicines yet to be discovered, shelter precious endangered species and provide wildlife tourism in the years to come. To protect these forest treasures as the 21st century marches on will require a herculean effort - one that involves enormous political will, the latest in agroforestry and land management - and perhaps a little extra assistance from flocks of unmanned aerial vehicles, spreading their life-giving seeds.
For his part, Tony Rinaudo has a powerful personal motivation for continuing his work in global forest regeneration. "Maybe my grandchildren will benefit," he reflects.
Source: The Age