Hazard Hemlock, working off a tight line
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rbtree
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Text on the YT vid:
This video is about a highly technical removal of a very dead and hazardous hemlock tree. The top of the extremely rotten lead had already failed and landed on a shed. We set three lines in an adjacent 120 foot Douglas-fir, one for life support, one for rigging and lowering the top of the intact trunk. The third was run through the dead tree 120-140 feet away to a small cottonwood, over it at about 40 feet and down to the ground. To that line, which is made of spectra, a high modulus fiber with nearly zero stretch, but very high strength, a second lifeline was attached, using a Hitch Climber pulley and alpine butterfly attachment knot. We chose to wait to get it set tight until Patrick of Westside Tree Care had climbed most of the way up, as there were many branches in the way of getting a straight shot prior to him climbing and cutting most of them. He did that, we got it set quite tight, and then he started working on the very dead and weak leader. He now had two overhead lifelines, plus his lanyard, so the margin of safety was increased to as best it could possibly be. He then worked the bad lead all the way down, then went back up and finished the job. Safety first. There was no access for a crane on this job. A mobile lift could have been used, but the size needed would have cost more than our price to do the job the way we did. This is now the fourth time, over my 46 year career of working in and on trees, that I have chosen to employ the use of a highline for life support. In all of the other three jobs, we also used the high line for rigging, which is to mean we lowered some tree sections using a rigging line also attached to the high line. In all those jobs, the loads we lowered were very light, so there was no risk of causing our anchor points to be overly stressed or fail. This is similar to the loading that a speed line (aka zip line or slide line) is subjected to. In fact, as the speed line is tightened to the point where the line angle deflection approaches zero, the loading on the anchors can approach infinity...which could mean a catastrophic failure of the anchors or any part of the system. Again, workers using such a system must have a knowledge of these forces, and set up the system in such a way that all operations will be safely within reasonable load ranges.
This video is about a highly technical removal of a very dead and hazardous hemlock tree. The top of the extremely rotten lead had already failed and landed on a shed. We set three lines in an adjacent 120 foot Douglas-fir, one for life support, one for rigging and lowering the top of the intact trunk. The third was run through the dead tree 120-140 feet away to a small cottonwood, over it at about 40 feet and down to the ground. To that line, which is made of spectra, a high modulus fiber with nearly zero stretch, but very high strength, a second lifeline was attached, using a Hitch Climber pulley and alpine butterfly attachment knot. We chose to wait to get it set tight until Patrick of Westside Tree Care had climbed most of the way up, as there were many branches in the way of getting a straight shot prior to him climbing and cutting most of them. He did that, we got it set quite tight, and then he started working on the very dead and weak leader. He now had two overhead lifelines, plus his lanyard, so the margin of safety was increased to as best it could possibly be. He then worked the bad lead all the way down, then went back up and finished the job. Safety first. There was no access for a crane on this job. A mobile lift could have been used, but the size needed would have cost more than our price to do the job the way we did. This is now the fourth time, over my 46 year career of working in and on trees, that I have chosen to employ the use of a highline for life support. In all of the other three jobs, we also used the high line for rigging, which is to mean we lowered some tree sections using a rigging line also attached to the high line. In all those jobs, the loads we lowered were very light, so there was no risk of causing our anchor points to be overly stressed or fail. This is similar to the loading that a speed line (aka zip line or slide line) is subjected to. In fact, as the speed line is tightened to the point where the line angle deflection approaches zero, the loading on the anchors can approach infinity...which could mean a catastrophic failure of the anchors or any part of the system. Again, workers using such a system must have a knowledge of these forces, and set up the system in such a way that all operations will be safely within reasonable load ranges.
pantheraba
More biners!!!
Smooth throw on the top....I saw him give a big puff of relief just after it went. Good show for sure. I like how that high line would have limited him swinging back into the TIP tree.
Try going smoother, slower on moving the camera from point to point. The details go away with quick movements (and make me vertiginous
).
Try going smoother, slower on moving the camera from point to point. The details go away with quick movements (and make me vertiginous
).
Marc-Antoine
TreeHouser
Interesting setup. I had never thought of a slanted highline like that.
A big thanks to the adjacent 120 foot Douglas-fir to make this removal less scary.
A big thanks to the adjacent 120 foot Douglas-fir to make this removal less scary.
rbtree
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Smooth throw on the top....I saw him give a big puff of relief just after it went. Good show for sure. I like how that high line would have limited him swinging back into the TIP tree.
Try going smoother, slower on moving the camera from point to point. The details go away with quick movements (and make me vertiginous
Thanks for the tip. I know I move the camera too fast when I'm shooting video and talking..... My bad!
Had I not had to add some stretchy True Blu to the 300' spectra tight line, we could have gotten it tighter.... had the intact stem been more suspect, it would have been nice to have had the tight line higher. I could have set it a bit higher in the Douglas-fir, but we had no available higher anchor point on the other end. If we'd needed to, I could have also set a third line in the adjacent cedar, which was off to the side....and not as high as we'd have liked. Didn't deem it necessary...
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