sentences:  However, this second sound is observed only at the microscale, because the wave dies out exponentially with
  characteristic length 1-10 microns.Therefore, presumably graphite in the right temperature regime has extraordinarily high thermal conductivity but only
  for the purpose of transferring heat pulses distances of order 10 microns, and for pulses of duration on the order of 10 nanoseconds.For more "normal" heat-transfer, graphite's observed thermal conductivity is less than that of, e.g, copper.