The Collaborative International Dictionary of English v.0.48:

Quicken tree \Quick"en tree`\ [Probably from quick, and first
   applied to the aspen or some tree with quivering leaves; cf.
   G. quickenbaum, quizenbaum, quitschenbaum. Cf. Quitch
   grass.] (Bot.)
   The European rowan tree; -- called also quickbeam, and
   quickenbeam. See Rowan tree.
   [1913 Webster]