gruner

n. 1. One who prunes, or removes, what is superfluous. [ 1913 Webster ]

2. (Zool.) Any one of several species of beetles whose larvæ gnaw the branches of trees so as to cause them to fall, especially the American oak pruner (Asemum mœstum), whose larva eats the pith of oak branches, and when mature gnaws a circular furrow on the inside nearly to the bark. When the branches fall each contains a pupa. [ 1913 Webster ]