Source : Webster's Revised Unabridged Dictionary (1913)

Arborous \Ar"bor*ous\, a.
   Formed by trees. [Obs.]

         From under shady, arborous roof.         --Milton.

Source : WordNet®

arborous
     adj : of or relating to or formed by trees; "an arborous roof"
           [syn: {arborical}, {arboreal}, {arborary}]