Source : Webster's Revised Unabridged Dictionary (1913)

Defoliate \De*fo"li*ate\, Defoliated \De*fo"li*a`ted\ a.
   Deprived of leaves, as by their natural fall.

Source : WordNet®

defoliate
     v : strip the leaves or branches from; "defoliate the trees with
         pesticides"

defoliate
     adj : deprived of leaves [syn: {defoliated}]