Today me and my three coworkers were removing a large Honey Locust from a small backyard. Two of us showed up first, I set my line and placed the other climber's line as well once I climbed up to my TIP. The other two arrived a couple hours later and one started rigging down pieces from both of us while the other dragged brush and chipped. At 2pm, the rigging guy had to leave for a class, so the other one switched to rigging down for us. Me and the other climber were working opposite sides of the tree and we each had our own rigging line, ring and block set up. We were using a GRCS as our only lowering device so were taking turns sending stuff. The guy rigging for us is the most experienced of all of us and is our lead climber, as well as the business owner, and is usually very sharp. I had tied off a large limb that was over a neighbor's garage and asked him for feedback on my plan. He totally changed what I had set up, which involved about 10 minutes of me moving around, changing the rigging configuration, setting a higher rigging point, etc. which I did. Once I had everything ready to go, I made my undercut and then verbally checked in with him as to whether he was ready, and he replied "Yep, I've got line and I'm ready when you are." He had me tie this piece near the middle because it was about 20' long and 7" diameter at the butt end and he felt it would possibly have hit the garage if I tied it near the butt due to it's length. Because of this I was focused on how the piece reacted when it came off in case he didn't let it run below me before it tilted. I made my back cut and it fell in the direction I had predicted but way too fast, and landed right on top of the neighbor's garage. He yelled "What just happened?" When I looked at him he was holding the wrong rigging line. I told him he had the wrong rope and he immediately acknowledged the mistake and even said that he knew I was using the other line and just screwed up. The garage had only a few damaged shingles, mostly due to the brush spreading out all the weight. Nobody was hurt either which is most important. There are plenty of takeaways from this for me. 1- Anyone can make a mistake, no matter how experienced. 2- I could have visualized him holding the correct rope prior to cutting, regardless of whether it seemed redundant or not. 3- having a second lowering device and having a line dedicated to each may have prevented this. 4- having two guys climbing and one guy rigging seems inherently less safe than one climbing and two doing ground work.











