In this experiment, conducted at The St. Anthony Falls Hydraulics Lab at the University of Minnesota. Tal and Paola looked the the influence of vegetation alone on the transition from braided stream to meandering stream pattern.

They grew Alfalfa periodically throughout the experiment and noticed a clear direct influence.

Details on the experiment and what is shown in the movie can be found at:

Tal, M., and Paola, C., 2007, Dynamic single-thread channels maintained by the interaction of flow and vegetation: Geology, v. 35, p. 347-350.