My hedge is beech, birch and holly. I prune by hand
My cherry trees (geans) I prune using a set of pruners and a laplander. In all the years I've done so I've never had the fungus thing, and we are very wet here. I didn't know that cherries produced resin, but apparantly that's a side effect of the fungus, since mine didn't have that, nor from what I can see do any of the other cherries around, I didn't know of the resin.
T'was interesting
Commercial cutting of hedges, and by that I mean field and roadside hedges is obviously a cost cutting exercise, but if it didn't work, if it actively killed off or overly degraded the hedge, then I doubt the practice would be continued as widely as it is.
I still think being aware of what you are doing, of what you are going to leave behind, as well as the decent removal of the bit of timber you want, is no bad thing.
Lot of good information coming out though
cheers,
M