The Collaborative International Dictionary of English v.0.48:

Planch \Planch\, v. t. [imp. & p. p. Planched; p. pr. & vb. n.
   Planching.] [F. planche a board, plank. See Plank.]
   To make or cover with planks or boards; to plank. [Obs.] "To
   that vineyard is a planched gate." --Shak.
   [1913 Webster]