Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
MUL'BERRY TREES. All agree that this is a mistranslation, but many different renderings are suggested. Some of the best recent authorities advocate the aspen or poplar, a few species of which grow in Palestine. The "going" in the tree-tops, which was to be the sign that God went out before the host, 2 Sam 5:23-24, may have been the rustle of these leaves, which are proverbial for their readiness to tremble before the slightest breeze.