1922  There was no path between the slim, close-growing trunks of poplar and balm, and we had to make progress as best we could.
1958  . . . poplar and balm trees which could be cut and rolled into position for the house.
1962  Sometimes in the narrow valley the spruce gave place to great black poplar-trees; 'bam-trees' in the vernacular. They are called 'bam' as an abbreviation for Balm of Gilead; well named for the aromatic smell of their buds in springtime.