Low elevation remote sensing of our silvopastures shows slightly reduced pasture production in the center of alleys between tree rows. We have attempted to reduce this effect by encouraging sheep to browse the lower tree limbs so that they can easily see under them. A related off shoot of this principle is that you do not want trees planted near gates. I have spent a lot of frustrating time trying to get sheep to move through an open gate. They see the tall grass and trees as a fence line and will not pass through.
Livestock can be extremely difficult to herd in grid or cluster silvopastures.
Animals attempt to maintain a personal space between them and a potential predator such as a herder. As you approach them, they will walk away to preserve this space. Once this space is reestablished, they will often stop and look around to see that is happening. Once livestock pass behind a tree, they lose sight of you. They assume that you can't see them, so lose all interest in being herded.