Sorry but incorrect. Branches can often fly high into the air due to the convection near a fire. I have had flaming branches pass my aircraft between 1,000-1,500 feet AGL near a fire.
Typical drop height is 150’ over lighter fuels (grass and sage) to 220’ over heavier fuels (trees).
The day previous to this incident, a BAe-146 was struck on the top of the fuselage while maneuvering for a drop as he was still a couple hundred feet over the ground.