murphy4trees
TreeHouser
The term balance point rigging was just used by Cory in the video thread: http://www.treebuzz.com/forum/showflat.php?Cat=0&Number=188543&page=0&vc=&PHPSESSID=
This is concept that Mark Chisholm teaches in his rigging seminars, and was used extensively to safely manage monster pieces by my teacher, Big Jon Grier. Its an advacned technique with many applications. Allowing a lot more control of movement thus reducing shock loads, and improving control for ground men. There has been some good discussion at the above thread. Worth reading if you have an interest.
The basic idea is to tie off a piece getting lowered, at or near its balance point (center of gravity), steer it to 4 or 5 o'clock with the notch, and let is swing smoothly into rope until nearly all the weight of the limb is on the rope before the hinge tears, thus greatly reducing shock loads. Real pretty and fun for both climber and ground crew, though both have to work together to keep it safe.
I used the same concept today in two different jobs, not to control shock loads, but to make the pieces easier to handle on the gound.
First job was a dry 21" dbh, 60-65' white pine, backyard on the low side of a 4' retaining wall from the driveway. Rigging the trunk off itself, tied the pieces a little high above the notch so they came down balanced, allowed for easier control and more ground clearance when using the chipper's winch to pull the pieces onto the driveway.
Second job was a broken hanging 35' maple lead, maybe 12-14". Customer had cut all the brush off. It was hung up on the ground at nearly a 45º angle. Tied it off a good ways down from the break. Cut the tips back to where it was floating balanced which made it easier to handle, to pull out away from the bushes under the tree, onto the lawn.
Not rocket science, but did make the jobs a little easier.
This is concept that Mark Chisholm teaches in his rigging seminars, and was used extensively to safely manage monster pieces by my teacher, Big Jon Grier. Its an advacned technique with many applications. Allowing a lot more control of movement thus reducing shock loads, and improving control for ground men. There has been some good discussion at the above thread. Worth reading if you have an interest.
The basic idea is to tie off a piece getting lowered, at or near its balance point (center of gravity), steer it to 4 or 5 o'clock with the notch, and let is swing smoothly into rope until nearly all the weight of the limb is on the rope before the hinge tears, thus greatly reducing shock loads. Real pretty and fun for both climber and ground crew, though both have to work together to keep it safe.
I used the same concept today in two different jobs, not to control shock loads, but to make the pieces easier to handle on the gound.
First job was a dry 21" dbh, 60-65' white pine, backyard on the low side of a 4' retaining wall from the driveway. Rigging the trunk off itself, tied the pieces a little high above the notch so they came down balanced, allowed for easier control and more ground clearance when using the chipper's winch to pull the pieces onto the driveway.
Second job was a broken hanging 35' maple lead, maybe 12-14". Customer had cut all the brush off. It was hung up on the ground at nearly a 45º angle. Tied it off a good ways down from the break. Cut the tips back to where it was floating balanced which made it easier to handle, to pull out away from the bushes under the tree, onto the lawn.
Not rocket science, but did make the jobs a little easier.