Originally Posted by
acercanto
As an arborist, I think I may be able to shed a bit of light on the subject. I climb trees all day and my rope sits and slides and runs through many crotches in a given tree, and over the years I've been back up in trees I've climbed before and not seen any residual damage to the tree.
That said; I do use a type of strap called a Cambium Saver on very thin-barked trees such as Beech, Maples, and Pines. But other than those few, anything with bark over 1/2"-3/4" or so is IMPO (in my professional opinion), quite fine for running rope over, given that it's not tiny, like 7/64" Amsteel Blue or something.
Hope that's a bit clearer than mud...
Acer