They sacrifice on the tops of the mountains, And burn incense on the hills, under oaks and poplars and terebinths, Because its shade is good. Therefore your daughters play the prostitute, And your brides commit adultery.
Under oaks - (white) poplars and elms (probably the terebinth or turpentine tree) because the shadow thereof is good The darkness of the shadow suited alike the cruel and the profligate deeds which were done in honor of their false gods. In the open face of day, and in secret they carried on their sin.