Charles Ellicott Commentary Ezekiel 19:11

"And it had strong rods for the sceptres of them that bare rule, and their stature was exalted among the thick boughs, and they were seen in their height with the multitude of their branches." — Ezekiel 19:11 (ASV)

Thick branches should rather be translated clouds. It is a hyperbolical expression within this imagery, to express the excellence of the vine of Israel.