I have really been looking into this since I was questioned on it. I have not came across anything definitive but here are some resources I have found and maybe as a community we can dig until we find the proper answer
Cinching and retrievable anchor for spar work in tree removals
Clipped from :
Rescue, Safety, and SRT Webinar w/ Rich Hattier from ISC - TreeStuff.com
Clipped from :
Arborist SRT canopy /spar anchor with dmm ring
Clipped from :
How to Clean and Maintain Climbing Carabiners w/ Taylor Hamel - TreeStuff Webinar Series
Clipped from :
Test on choked carabiner as anchorage.
Clipped from :
Finally I will note that Petzl has the referenced Tether option depicted at the following link
https://www.petzl.com/US/en/Profess...ngle-mode-with-CHICANE?ActivityName=Tree-care>
Hope this helps and again I am not promoting either option and only sharing what I have found in my own search.