Rashi: It is an expression of Yofi (beauty). Radak ? the root is Yafeh; the first Yud is from the conjugation. The last letter of the root is omitted.

Rashi: They are branches that extend a long way in every direction, like vines draped on poles in a vineyard.

Radak: They are the tall branches. This is like "Aromimcha Hashem Ki Dilisani" (Tehilim 30:2).

Malbim: [Normally,] when a tree grows more and sends out long branches draped [on supports] more than is proper, it is not beautiful. Usually the branches wilt and the leaves fall off, and [the branches] weaken the tree. Therefore, they prune them and cut them off. However, this tree is beautiful with its long Daliyos, for its root is on much water. The Nimshal is, if a weak king extends his kingdom a long distance, it will not last. He needs to send soldiers outside, and he is not secure from internal rebellion. However, [Melech Ashur] was very strong. Even though [his reign] spread to distant lands, since he was powerful, he was rooted and strong in his land.