The Collaborative International Dictionary of English v.0.48:

reafforest \re`af*for"est\ (r[=e]`[a^]f*f[o^]r"[e^]st), v. t.
   To convert again into a forest, as a region of country; to
   re-establish a forest after clear-cutting or fire, etc.; --
   used more often without the hyphen.
   [1913 Webster + WordNet 1.5]

WordNet (r) 3.0 (2006):

re-afforest
    v 1: reestablish a forest after clear-cutting or fire, etc.;
         "re-afforest the area that was burned during the fighting"