Keeping exposure timing less than a half second has another benefit besides tack sharp leaves and branches. If someone inadvertently walks into your long-exposure framing, you can take that opportunity to include the person in your composition with a lesser probability that that person will blur out.

I was so happy to take this shot. The person in the photo counterbalances the waterfall in the overall structure of the composition. This balance shifts the attention away from the waterfall as the main subject adds another dimension to the composition, which would otherwise be a predictable and bland photo.