Drop zone
Also called: fall zone, felling zone, landing zone
The area where a felled tree, or pieces of a tree being dismantled, will land. For a whole-tree felling it should be clear for at least one and a half times the tree's height in the fall direction, with nothing valuable within that radius on any side.
Whether a tree has a usable drop zone is the single question that decides whether it can be felled whole (fast, cheap, DIY-possible) or has to be taken down in sections (slow, expensive, professional). Houses, fences, sheds, vehicles, power lines and other trees all shrink it.
The 1.5× rule accounts for the tree not falling exactly where intended, the top whipping forward on impact, and the butt kicking back off the stump. Pros also clear a “retreat zone” for themselves — two escape paths at 45° behind the tree.
When a crew lowers sections on ropes instead of felling, the drop zone is just the small area directly below where each piece is cut, which is why sectional work can happen inches from a roof.