drop zone
predetermined area where cut branches or wood sections will be dropped or lowered from a tree (see landing zone).
drop-crotch pruning
(obsolete) term for a method of reducing the height of a tree. The general rule for cuts is that leaders should be cut back to a lateral capable of assuming apical dominance. impossible. usually at least one-third the diameter of the leader (see reduction).
drought
period of unusually low precipitation.