and as we reached the summit of the final pass , i thought i might explode from simple joy at the scent of the late-spring woods , an intoxicating mix of pine and balsam fir , oaks mingling the spice of fresh green leaves with the must of the winter 's fallen acorns , and the nutty sweetness of chestnut mast under a layer of wet dead leaves , so thick that it made the air seem buoyant , bearing me up .