Source : Webster's Revised Unabridged Dictionary (1913)

Afforest \Af*for"est\, v. t. [LL. afforestare; ad + forestare.
   See {Forest}.]
   To convert into a forest; as, to afforest a tract of country.

Source : WordNet®

afforest
     v : establish a forest on previously unforested land; "afforest
         the mountains" [syn: {forest}]