For several years members of a Special Forces team serving in Afghanistan would wear beards - as this would help them earn the trust of the Afghans. Afghan men, at least in the Pushtu south, see a beard as a sign of maturity, respect, and manhood. In southern and eastern Afghanistan a man without a beard is sometimes seen as a communist, from northern Afghanistan (Tajik, Uzbek, or Hazari), or gay.
It seems the days of Special Forces Soldiers wearing beards in order to build rapport with the Afghans are over. Now they are shaving off their beards in order to build rapport with conventional battle space owners (brigade commanders who own the turf where SF ODA's operate). Read more in "Some special ops troops told to lose the beard", Stars and Stripes, August 19, 2010.