The Collaborative International Dictionary of English v.0.48:

Whitewood \White"wood`\, n.
   The soft and easily-worked wood of the tulip tree
   (Liriodendron tulipifera). It is much used in cabinetwork,
   carriage building, etc.
   [1913 Webster]

   Note: Several other kinds of light-colored wood are called
         whitewood in various countries, as the wood of
         Bignonia leucoxylon in the West Indies, of
         Pittosporum bicolor in Tasmania, etc.
         [1913 Webster]

   Whitewood bark. See the Note under Canella.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Bass \Bass\, n. [A corruption of bast.]
   1. (Bot.) The linden or lime tree, sometimes wrongly called
      whitewood; also, its bark, which is used for making
      mats. See Bast.
      [1913 Webster]

   2. (Pron. ?) A hassock or thick mat.
      [1913 Webster]

WordNet (r) 3.0 (2006):

whitewood
    n 1: light easily worked wood of a tulip tree; used for
         furniture and veneer [syn: tulipwood, true tulipwood,
         whitewood, white poplar, yellow poplar]