The book associates the Palmer with an oak tree; because it has previously tied the oak to Cedric and his servants, this continues to suggest that the Palmer might really be Ivanhoe. Certainly, Isaac sees through at least part of the Palmer’s disguise, easily identifying him as a knight. This suggests that chivalry does have value to society, since it encourages people to behave in recognizable and recognizably pro-social ways (like helping Isaac with no hope of reward).