Why is there an Aleph at the end of "Gavha"?
Radak: The Aleph is in place of a Hei (Aleph, Hei, Vov and Yud are interchangeable).
Why did it grow more than all other trees?
Malbim: It received the primary influence.
What are "Sar'aposav"?
Rashi: Its branches.
Malbim: They are big branches that hold the small branches.
What are "Porosav"?
Rashi: Its small branches. Malbim ? in a fruit tree, they bear the fruits. There are many of them. They are at the top of the tree, or at the end of the big branches, like Pe'er [a turban] or hat. They are called Porosav because they are long and bent, and give Pe'er (beauty) to the tree.
Radak: Sar'af, Sa'if (in the coming verse) and Porah are the same (branches) ? "Mesa'ef Purah" (Yeshayah 10:33). The matter is repeated in different words.
What do we learn from "mi'Mayim Rabim b'Shalecho"?
Rashi: [Its small branches] grew due to much water. An expression of Shilu'ach applies, like "va'Tishlach Poros" (17:6).
Radak: [The branches grew] due to much water that the Tehom sent.
Malbim: The branches became long and thick via much water.
