Thanks for asking. When I first saw this, I had no idea what had been done to the tree. But several other trees nearby had the same markings, which made it hard to dismiss as random damage. After some digging, it turns out this is deliberate: people strip the bark from pine trees to collect resin (sap). Pines release resin when the bark is cut or peeled, and historically it was used for pitch, waterproofing, glue, torches, and medicinal purposes. In some places, resin is still farmed this way today.