Trees eat almost anything in soil, as long as the soil is tender enough.
Desert cannot be the habitat for most trees due to its solidity.
To make it tender, why not bombing that desert? Put the water and you got a fertile land with various trees.
Flood is among others caused by over loaded water in rivers, and to decrease the amount of the water in cities, or populated places, why not creating a lot of ponds at the sides of a river from remote positions to near cities
Bombing is the effective quick method for it.