Well, the answer is it depends: it depends on the severity of the fire and the duration of the fire. Your trees will likely bounce back quickly if fire intensity was low and if fire exposure was minimal; however, I can't guarantee your "browned" branches will reflush with green needles.
Therefore, the only way to accurately assess the damage caused by this grass fire is to contact a local professional forester or a local certified arborist for an on-site assessment.
Maryland Arborist Assoc.: http://www.mdarborist.com/
Best of luck!