[Inspired]

I don't know that it matters, line voltage or low voltage. You still have to fasten a light fixture so the light can be directed somewhere consistantly and you still have to secure the wire or conduit somehow.

Let me back up a little...

The idea of lights up in a tree is to provide an interesting effect on the ground. Some people like to use a lite-blue lense and call it "Moon Lighting" casting shadows a bit like a very full moon. Sometimes the idea is to focus your attention on a certain object like a sculpture or architectural element.

What I see a lot is deep scars, wiring and fixture mounts that get swallowed up by the tree or some sort of strange looking branch shape that lead me to believe the tree isn't exactly happy with the situation. It seems most lighting people use screws to mount the fixtures and staples to mount the wire, collect a check and leave. A couple years down the road the tree has reacted to the screws and staples. Maybe this isn't a problem but it worries me that the aluminum mounts, steel screws and copper wire will eventually harm the tree.