This seed carrier, powered by rain, could help reforest the most remote areas

By | December 18, 2023

The world’s forests are under threat. Rising global temperatures are not only causing more intense forest fires, but also causing timber to be cut and cleared to make way for agriculture. This year is expected to be the hottest year on record and the worst on record for fires in the boreal forests worldwide.

Reforestation is essential in the fight against climate change and to protect biodiversity, but planting saplings by hand can be slow and labor-intensive.

In recent years, drones have been used to drop seeds on land deforested by forest fires; a company called Mast Reforestation, formerly DroneSeed, has used 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 a forest to regrow, fallen seeds must get into the soil and germinate, and that can be a challenge.

Researchers at 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 intended to be dropped and drilled into the ground by drones.

But remarkably, the wearer doesn’t need an energy source to drill into the ground; it is made of a material that ‘self-drills’ in response to rain.

Lab director Lining Yao and her colleagues looked to erodium seeds for inspiration.
The seeds of this plant genus have a spiral-like ‘borer’ that changes shape when wet, using a ‘tail’ to hold itself upright and push into the soil more effectively.

The team created a seed carrier based on the same principle, made from white oak that responds naturally to changes in humidity. They chemically treated the wood to make it more flexible when wet, but also softer and denser so it expands more effectively. Erodium has one tail, but the seed bearer has three, which makes it easier to drill into the ground.

According to research Yao published in the journal Nature, the carrier has an “80% success rate when drilling on flat land,” making it more effective than erodium seeds under the same conditions. After the carrier burrows, the seed is protected from animals and the natural elements, increasing the chances of germination.

Handmade

In August, the design won the Falling Walls Breakthrough of the Year award – awarded annually to scientific breakthroughs in academic disciplines – in Engineering and Technology.

So far, Morphing Matter has only tested the seed carriers at locations in Pittsburgh and Changxing, China, but Yao says the lab has received interest from venture capitalists and government agencies around the world looking to use the seed carriers in reforestation projects.

But she notes that specific types of seed carriers need to be developed for different locations, including to accommodate different soils and moisture levels. “We have to tailor the design to local conditions and the seeds of their interest,” Yao explains.

“The desert is very different from the Amazon rainforest and the coastline around Hawaii.
The partnership needs to work closely with local practitioners, so we always ask them to send seeds and soil so we can validate them.”

The seed carrier is made of treated white oak.  - Morphing Matter lab

The seed carrier is made of treated white oak. – Morphing Matter lab

To deliver the technology to projects around the world, production would have to be scaled up.

“Most people who reach out want thousands of seeds, they want to grow millions of trees a year,” Yao says. “I have set up a small team in the lab to think about the mass production strategy, but we definitely want to get more financial and human support to make this a bigger effort.”

Shu Yang, a professor at the University of Pennsylvania, has been deeply involved in the E-seed carrier project. She says the issue of large-scale distribution is important.

“You have to look at efficiency. Right now it’s 80% and once you tackle a large area, what’s the efficiency versus the cost? … Whether or not people are interested in this, I think the success rate is critical.” Yang says.

But in terms of the production process, Yang believes it will be possible to produce enough carriers to meet demand.

Seed deficiency

According to Matthew Aghai, vice president of bioresearch and development at Mast Reforestation, the e-seed project is a “phenomenal development,” but he adds that for seed distribution to be truly effective, better drones will be needed on a larger scale should be made available for reforestation. . With conventional drones, the technology is generally not in a place where you can operate with a high degree of control and precision, he says.

Mast Reforestation has worked on projects all over the world.  - Mast reforestationMast Reforestation has worked on projects all over the world.  - Mast reforestation

Mast Reforestation has worked on projects all over the world. – Mast reforestation

Mast previously manufactured and used drones for reforestation and continues to use them in research and development, but is not currently using them in reforestation projects. It also produces millions of seeds annually at the largest seed bank in the western United States, and while it has no ties to Morphing Matter Lab, it has had discussions about it. Aghai adds that using drones for reforestation in remote areas requires infrastructure such as charging stations, which are often unavailable.

But an even bigger challenge could be a shortage of seeds, he says, because storing seeds in banks takes time and seed farms need more financing. “There is actually a broader seed shortage in our industry, a very serious shortage. That is the bottleneck for reforestation, not for the technology.”

Editor’s note: This story has been updated to clarify Mast Reforestation’s use of drones.

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