That's frustrating! Even a general book on the subject, or one that just presents various techniques that have worked and are applicable to arborists would be useful! The books that I've found that are more for urban rescues or for fire departments or whatever almost all focus on large equipment, or things like rappel racks and backboards and things that it's fairly unlikely an arborist's crew is going to have access to out in the woods. Seems like there should at least be a pamphlet about "here's how you go up the climber's line, or one set right next to it, and pick them off their line, and come down safely."
I used to always climb a basal anchor that was rigged to a rescue 8 so that my wife could lower my limp, unresponsive corpse down after I do something stupid. Then I had a pretty close call with severing the line near the basal anchor from something that I don't think anyone could have ever foreseen happening, so I've gone almost completely to canopy tie-in-points... which made me start thinking about how someone/emergency services might be able to fetch me down in the event of a debilitating accident. Pretty bleak really.