The Collaborative International Dictionary of English v.0.48:

Pyrography \Py*rog"ra*phy\, n. [Pyro- + -graphy.]
   A process of printing, ornamenting, or carving, by burning
   with heated instruments. One variant is wood burning.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

pyrography
    n 1: the act of producing drawings on wood or leather by using
         heated tools or a fine flame