The last year's Castle Fire in California's Sierra Nevada killed over 10 percent of the world's largest sequoias. These trees are the tallest on Earth. Sequoias are able to survive many fires in their lives, and can live for thousands of years. Their bark is fire-resistant, so they rely on fire to reproduce. Wildfires are becoming more intense and larger as the climate changes intensify. Six of the seven most destructive wildfires in California history occurred within the last year, according to state officials.
A few young companies are looking to use drones to spread seeds and help with the restoration of fire-ravaged forests. Flash Forest, CO2 Revolution and at least threeDendra Systems have pledged to plant one billion trees or more.
It is not clear, however, how efficient drone-driven reforestation can prove to be. A study showed that only 20% of drone-dropped seeds actually take root and become trees. WIRED did not get any information from the companies that had been contacted about how many trees they have successfully grown.
A new problem is now facing forestry officials: a shortage of seeds that will last for many years. This has prompted them to make the best use of all they have.
California Department of Forestry and Fire Protection was considering partnering with DroneSeed to help rebuild Mountain Home State Forest. DroneSeed is a Seattle-based company that uses drones about the size of washing machines. The plan was canceled.
Chief Stewart McMorrow is the supervisor of Cal Fire Reforestation Center. He has been running the state's tree seed bank since 1950s. He believes that planting trees with drones might be a good idea. He says it is difficult to test the idea if there are not enough seeds.
McMorrow states that while we want the DroneSeed option to work, the current way it works is not viable. It is clear that the amount of seeds needed to make it work is insufficient to support the number of seeds available.
It is not viable because of the way it functions right now.
It is especially attractive to plant trees from the skies in difficult-to-reach areas. Burned slopes are also susceptible to erosion and mudslides. According to the UN Intergovernmental Panel on Climate Change, it has the potential to accelerate reforestation-one of the most powerful weapons for combating climate change. According to the US Forest Service, replanting federal land could cut the nation's carbon footprint by 14%. A group of scientists from around the world stated in a 2019 paper, that there was enough land on Earth to plant hundreds and billions of trees. This could help reduce atmospheric carbon levels by 25 percent.
The effectiveness of drones in helping is dependent on the number of seeds that are dropped by drones. This can be affected by factors like flight path, distribution, speed of seeds and whether or not they are eaten by wildlife.
Robert McNitt, the creator of the Forest Seedling Network which maps seed locations to specific areas in Idaho, Oregon and Washington based upon elevation, believes there are many people who have big ideas for drones. McNitt began planting trees in 1950. He did some aerial seeding in Oregon in the 1960s that he described as unsuccessful. He says that it takes more than just scattering seeds to make a forest.
For a drone-fired seed to be successful, not all seeds must germinate. Flash Forest, a Canadian startup, claims that two drone pilots can scatter up to 100,000 seeds per day. A person who works by hand can plant approximately 1,000 seedlings per day.
Researchers from over a dozen universities and government agencies in seven countries released a landmark study this summer. They concluded that drone seeding could restore forests and cool the earth, but that it faces challenges due to low seed survival rates, as well as other obstacles.