Ivy vines (often poison but that's another topic) can be tricky sometimes. Once a tree becomes just a structure for the climbing plants, many of the older dead vine columns are detached but when getting to the top is the objective we don't notice which ones are stable and connected and which ones are "loose". Have had lot's of surprizes while ascending.
Also have come across a few trees that were long rotted and gone, leaving only a braidwork of 60' of woody vine tubes. Those are cool, especially if you have a camera. One time had the chipper backed-up to the base of a straight water oak and cut a girdle, pulling a feed into the chute....it took the entire vine off the tree but damn if there was no one around to see it happen. Two days after most girdle cuts - if it's not raining - it's easy to pull the climbers off, at least as far as the canopy, then it's gloves and anti-itch cream that night.
Also use the pole gaffs, no more pines here in the Hill country. Density of dead live oaks mandate the short ones if I need them, but keep them sharp as often as I rat-tail file my 020's. It's also nice to be able to walk from truck to tree to tree without tip-toe 'ing because of long gaffs.
Heck, better quit stalling and get to work.