by The world’s forests are under threat. As well as being logged for timber and cleared to make way for agriculture, rising global temperatures are causing more intense wildfires. This year is set to be the hottest on record and the worst on record for fires in boreal forests around the world.
Reforestation is essential in the fight against climate change and to protect biodiversity, but removing saplings can be slow and labor intensive.
In recent years, drones have begun to be used to plant seeds on land deforested by wildfires; a company called Mast Reforestation, formerly DroneSeed, has implemented this method in the western United States and beyond, and the World Wildlife Fund has used specialized drones to restore rural bushland in Australia. But for reforestation to regrow, fallen seeds must penetrate the soil and germinate, and that can be a challenge.
Researchers from the Morphing Matter Lab at Carnegie Mellon University, in Pennsylvania, may have an answer. Inspired by nature’s own design, the lab has created an “E-seed” carrier that is intended to be dropped by drones and drilled into the soil.
But amazingly, the carrier doesn’t need an energy source to drill into the ground – it’s made of material that “self-drills” in response to rain.
Laboratory director Lining Yao and her colleagues looked to helium seeds for inspiration.
The seeds of this plant genus have a coiled “drill” that changes shape when wet, using a “tail” to propel itself and push itself into the ground more efficiently.
The team created a seed carrier based on the same principle, made of white oak wood that naturally responds to changes in humidity. They chemically treated the wood to make it more flexible when wet, as well as being softer and denser so it expands more efficiently. The tiller has one tail, but the seed carrier has three, making it easier to drill into the soil.
According to research published by Yao in the journal Nature, the carrier has an “80% drilling success rate on flat ground”, making it more effective than erodium seeds under the same conditions. After the carrier holes, the seed is protected from animals and the natural elements, improving its chances of germination.
Customized
In August, the design won the prestigious Falling Walls award of the year — given annually for scientific progress in academic disciplines — in Engineering and Technology.
So far, Morphing Matter has only tested the seed carriers at sites in Pittsburgh and Changxing, China, but Yao says the lab has received interest from venture capitalists and government agencies around the world who want the carriers. use seeds in reforestation projects.
But she notes that specific types of seed carriers must be developed for different locations, to accommodate different levels of soil and moisture, among other variations. “We have to adapt the design to local conditions and the seeds of interest,” explains Yao.
“The desert is very different from the Amazon rainforest and coastlines around Hawaii.
The partnership has to be very collaborative with local practitioners so we always ask them to send us seeds and soil to validate.”
To make the technology available for projects around the world it would be necessary to increase production.
“Most people who reach out want thousands of seeds, they want to grow millions of trees in a year,” says Yao. “I started a small team in the lab to think about a mass production strategy, but we would definitely like to get more financial support and personnel to make a bigger effort.”
Shu Yang, a professor at the University of Pennsylvania, was heavily involved in the E-seed carrier project. She says that large-scale distribution is an important issue.
“You have to look at the efficiency. Right now it is 80% and then when you do a large area, what is the efficiency against the costs? … Whether people are interested in doing this, I think the success rate is key.” said Yang.
But in terms of the manufacturing process, Yang believes it will be possible to produce enough carriers to meet demand.
Scarcity of seeds
According to Matthew Aghai, vice president of bio-research and development at Tree Reforestation, the e-seed project is a “fantastic development”, but he also says that better drones need to be made more widely available for reforestation if seed distribution is to to be truly effective. . Typically, with traditional drones, “The technology is not at a place where you can operate with a great degree of control and precision,” he says.
Tree has previously manufactured and used drones for reforestation and still uses them in research and development, but does not currently use them in reforestation projects. He also produces millions of seeds annually at the largest seed bank in the western United States, and although he is not involved with Morphing Matter Lab, he has consulted with it. Aghai says that using drones for reforestation in remote areas requires infrastructure, such as charging stations, which is often not available.
But seed shortages could be a bigger challenge, he says, because it takes time to store seeds in banks and seed nurseries need more funding. “There is a wider seed shortage in our industry, which is very serious. That’s the barrier to reforestation, not technology.”
Editor’s Note: This story has been updated to clarify Mast Reforestation’s use of drones.
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