https://www.biocarbonengineering.com/ These guys use drones to shoot tree seeds in the ground.
Also regarding terraforming a dessert, I think one of the biggest problems with is the number of water needed in the area, but I do think that this will be a really interesting part of the solution. Maybe the increase of land prices due to the decrease of arable land might make such ventures more profitable. There's a great ted talk about reversing desertification: https://www.ted.com/talks/allan_savory_how_to_green_the_worl...
Given that you need to do this once every 25-40 years (maturity cycle of the tree), is doing it with drones really that big a win?
Historically non violent direct action has been successful in changing politics (see womens suffrage, civil rights movement). This is the primary goal of the Extinction Rebellion http://extinctionrebellion.org
1. Automate tree/crop planting
2. Reform regulations stipulating that planting of trees/crops/plants should be required on any and all uninhabited lands, as a matter of "imminent domain" regardless of the land owner. Perhaps even as a tax incentive to land owners.
3. The development of a maintenance and management policy and system around all that is planted
4. In conjunction with the RFS for flooding deserts, develop a multi-stage water transfer to desert desalinization ponds, then to be used in irrigation of the tree planting efforts.
We already have autonomous farming combines with excellent ability to harvest crops and plant seed. They should be put to use at scale in panting trees.
Further, we could make an effort to employ the vast amounts of humans with little opportunity to be productive to build, plant and deploy a massive effort such as this.
We dont need to try to do everything with robots, when we have millions and millions of humans.
If we are so progressive and smart, maybe learning how to manage a labor force in the millions to accomplish a great work such as terraforming a desert is someting we should attempt again.