The Collaborative International Dictionary of English v.0.48:

forested \for"est*ed\ adj.
   covered with forest; as, efforts to protect forested lands of
   the northwest.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

forested
    adj 1: covered with forest; "efforts to protect forested lands
           of the northwest"

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "forested":
   afforestational, arboreous, bosky, braky, bushy, copsy,
   dendrologic, forest, forestal, reforestational, scrubby, shrubby,
   silvicultural, sylvan, timbered, wooded, woodland, woodsy, woody