The Collaborative International Dictionary of English v.0.48:

Lumber \Lum"ber\, v. t. [imp. & p. p. Lumbered; p. pr. & vb.
   n. Lumbering.]
   1. To heap together in disorder. " Stuff lumbered together."
      --Rymer.
      [1913 Webster]

   2. To fill or encumber with lumber; as, to lumber up a room.
      [1913 Webster]