(This article was first published on Fire Aviation)
Replanting trees after a wildfire or logging operation is an extremely labor intensive and expensive task. Carrying a bag of seedlings and using a dibble bar or shovel across steep debris-covered terrain can wear out a human.
A new company, DroneSeed, has a solution. Use machines. They are designing a system around a swarm of drones that can plant tree seeds in places where they have a decent chance of survival. First they survey the area with a drone using lidar and a multispectral camera to map the terrain and the vegetation. Software then identifies the areas that have invasive species or other plants the landowner wants to eliminate and then a drone applies herbicide to only the patches that need it, rather than dumping pesticide over the entire landscape.
According to an article at TechCrunch, DroneSeed is still fine tuning the seed dispersing system, but the next step is to use artificial intelligence to sort through the mapping data to find microsites where a dropped seed is most likely to germinate.
Using a concept that has been around for a long time, they will coat the seeds with substances that will enhance its survival chances. The article explained that the company is very reticent to detail exactly what will be applied to the seed. In agriculture, seeds are often coated with polymers, fertilizers, or fungicides. Polymers can improve the flowability and plantability — if the weather is hot and humid, cool and damp, or dry — to get consistent seed drop.
One issue DroneSeed appears to be concentrating on is deterring animals from eating or removing the seeds. They are looking at adding capsaicin, a chili pepper extract, to the coating. A fertilizer, if included, would wash off during a rain and then supply nutrients to the seed as it germinates.
The drones they are using are off the shelf aircraft that DroneSeed guts and converts into a machine that fits their missions. They are referred to as “heavy lift” drones since they weigh more than the 55-pound maximum for more conventional drones. The FAA limits heavy lifts to 115 pounds. The company says they are the first and only company the FAA has approved to use drone swarms to dispense agricultural payloads (fertilizers, herbicides, and water).
The FAA classifies this exception as “precedent setting”, referring to the exceptional lengths DroneSeed has gone to prove out its ability to scale operations to larger payloads for multiple concurrent flights.
As you can see in the video below, the drones are used in swarms, with five to six drones being able to equal the production of one helicopter when spraying herbicides.
DroneSeed has worked for three of the five largest timber companies since 2017 spraying herbicides, but they are just getting into the tree seeding game. They missed the prime planting season this year but were able to apply seeds to a few small sites and should be in a good position next year to show off their results.
I am curious what the survival rates are. Ariel seeding of grasses has been widely found to be ineffective and a waste of money: https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1140&context=jfspbriefs
Maybe I missed it, but where in that paper does it say aerial seeding, specifically, “has been widely found to be ineffective and a waste of money”. Most seeding of grasses, which is what that paper is about, are done to prevent erosion or maintain the presence of native species. Aerial seeding of trees is a different animal.
I was paraphrasing in my own words but the review of 94 other studies on the effectiveness of areal seeding found:
“According to 78 percent of the studies that evaluated soil erosion in both seeded and unseeded areas, seeding did not reduce erosion relative to unseeded controls. Even when seeding significantly increased vegetative cover, there was not enough plant cover to stabilize soils within the first 2 years after fire.”
“Out of 11 papers that evaluated the effectiveness of seeding to curtail non-native plant invasions, 54 percent indicated that seeding treatments were effective and 45 percent indicated that the treatments were ineffective. Of those treatments that were regarded as effective, however, 83 percent used non-native species (i.e., grasses and cereal grains).”
“Sixty percent of the studies indicated that seeding suppressed native plant recovery. However, long-term impacts were not studied.”
It is my understanding that the company intends to drop seeds to grow trees. Did the studies you referred to evaluate aerial seeding of tree seeds coated with polymers, fertilizers, or fungicides, and with the objective of growing timber, rather than preventing erosion?
That’s great. I remember when we used to use helicopters. They could carry 10 times the weight and seed miles of dozer line at once.