When Gandalf meets the The Three Hunters in Fangorn he says that Saruman has no woodcraft. What does he mean by this? What does it matter? What is woodcraft?
Gandalf is simply referring to Saruman's inability to read the tracks left by the orcs - whether through pure woodsmanship like Aragorn's or Legolas's, or through mystic means.
Saruman came to see his orcs bringing him the captured hobbits, whom he believed included the ringbearer, but discovered only a burning pyre where the Rohirrim had burned the bodies of the orcs. Had he more woodcraft, he might have found the tracks made by the hobbits as they escaped, but he didn't, so was left in the dark:
He has no woodcraft. He believes that the horsemen slew and burned all upon the field of battle; but he does not know whether the Orcs were bringing any prisoners or not.