Good morning Major, Is the trunk very wide and are there any accessible branches you could utilise? The problem as I see it is if you use wire, rope or any kind of strapping to clamp around the trunk then you risk strangling the tree. I assume you wouldn't want to fasten into the tree itself?

It’s a 20yr old cedar, I have pruned the lower branches, and it looks like a parasol to get light to the flower bed beneath it.It’s roughly 2ft in girth, there are a few thicker branches, but it is in the front garden. So I wouldn’t want them to get stolen.
I have some pots that you can strap to drainpipes; I wondered it there was anything like this for trees.
Thanks for your help.