If you strip the bark about 65% of the way around a tree or cannabis plant it will usually die. I've seen grey mold girdle almost completely around a ganja plant. As long as there's a strip of clean green bark the plant doesn't die.
Never, ever, snap off branches by hand. Always use snips, clips, razors, a knife, or whatever. You want a sharp clean cut. You'd think I'd have learned by now but I did the same shit earlier this year. It's clippers only for me.
Anytime you break the skin like that you're at risk of a fungal infection. I've tore the skin in July. Then three months later in flowering after a rain storm had grey mold attack the wound.
Most of the time you're okay though. You can tape or tie it up and it'll heal in a couple days if it's a bad one. Cannabis plants are fast healers and can take a lot of damage.
This is pruning season I'm going to be removing branches the next few days. It's dangerous, wish I didn't have to. Keep an eye on old wounds, broken branches, scrapes and such. Boytritis is always waiting for an opportunity. The stumps of old branches and leaves are places it loves to attack.