Several reasons come to mind: The helicopter overcomes its own weight. So, a similarly effective ground based solution would have to push up so much air as to

Several reasons come to mind: The helicopter overcomes its own weight. So, a similarly effective ground based solution would have to push up so much air as to push into the ground with at least twice its weight (well, or be heavier than a heli). Might run a risk of getting stuck. Next, the heli rotor blades are above the tree line, where there are no branches and no trunk. A ground based solution would necessarily be between the trunks. You'd have to not only protect the rotating blades by ducting them, but also have a much harder time navigating. Finally, helicopters exist already and have other use cases. Ground based vehicle would have to be specifically designed and built, and would not be useful for much else.