PM reply
Alright this one is a lot long... Its a piece I wrote as a response to a PM from Steven.
I post it here thinking it might benefit someone out there...And I welcome all feedback.
D
Brother Steven,
I appreciate your straigtfoward request for assistance and your earnest desire to learn good techniques...
I actually wrote a response before getting the below mail...
There are several advantages to using a block rather than natural crotch rigging, especially on these pines... Do you have the Sherril Catalog??? Gotta get one...the price is right too! Using a rigging block will allow much faster and easier rope movement (return) and will keep your line from getting all messed up with pine pitch, which in turn will help keep you cleaner... You can also tie the block onto any area of the tree, so you don't need to rig from a crotch, nor worry about that crotch failing. There will also be a constant amount of friction at the rigging point, which is the main advantage of using a block... This will make it easier for the ground person to judge how many raps are needed on the trunk, or preferably on the friction device... You'll need a Port-a Wrap to go with that rigging block...
So you'll need a rigging block, hopefully 15,000-30,000lbs. And a sling of similar strength to go with it. The sling is usually just a short 5/8-3/4" line with an eye splice on one end. Tie it with a cow hitch if you have anough line, otherwise use a timber hitch... Note: you can get away with using a short piece of good 1/2 line to tie the block to the tree... Take three or more wraps through the block to make sure it won't break... That should be alright on this job, especially since you won't be needing to move the block much, though if you plan on blocking down the spar, you'll definitely need a sling.
Your rigging line should always be the weakest link in the system and it is also recommended to keep the force on the rigging line to 10% of the tensile strength... That is keep the load on a 7,700 lb line to 770 lbs. That includes any force from shock loading... Arborists usually use the 10% mark on lines of any use as a safe working load (SWL). Other disciplines use 20%, so you can cheat that 10% from time to time, but don't make a habit of it, especially with shock loads... Repeated (over)loading will eventually cause the rope to fail.
Tough to tell from the pic, and it looks like the trees are close enough to rig all the branches from 1 place.... Normally the highest point that will work to give you a good landing zone and rigging point. Then work from the bottom up and butt tie the limbs so the tips drop first and hopefully come down soft on any structure in the way. You can also tie off and lower multiple limbs on any one lowering trip.. This can save a lot of time on pines, and you need to learn how to do it safely and efficiently.
I love to set up lowering lines in trees adjascent to the tree I Am working... That way when the piece lets go it swings safely away and should the lowering system fail, I'll still be going home for dinner.
So you can figure out which tree will be the easiest to fell. Set the block in that tree and use it to lower the limbs from both trees and then wood from the adjascent tree... Normally the wood would be lowerred by tip tying the piece to be lowerred... Use a pull line if necessary and just let the pices swing into the trunk. Even if you have to take short pieces, 2-5', you'll still be able to control their descent.... Once the tree is short enough, fell it...
Then you could use a techique called "blocking down the spar" to remove the last tree... You wrote "Even in theory, I don't understand how you can set up a block and pulley below the piece that is being cut b/c in my mind the piece would be free falling for a little bit until it passes/falls below the block/pulley point" That is exactly what happens, and this free fall can create tremndous force on the rope and rigging point. The late Peter Donazelli (sp?) did some nice work on the physics of forces involved in such rigging. Its really not that difficult to learn if someone shows you... I wouldn't feel comfortable trying to coach you through learning that in writing though... Plus we've got a hurrican due tomorrow and I shpould get some sleep... So you need to hire someone that knows how to do that or find someone to teach you. There are also some rigging videos that would show you pretty well.
I might consider trying to use the big wood from the first tree to protect the shrubs, and fell the second from the ground (after removing the block of course). You could also use a pull line to fell a bigger section off the top of the second tree and let it freefall, but you should have more experience before trying that and get that exerince in non-critical situaltions... And even then there is a chance the piece could land wrong and fall or bounce back into the house...
You could also bomb small pieces and push 'em away from the house... just remember to keep the drop zone clear as you go so the falling piece doesn't take a bad bounce off a downed piece and into the house. Also plan on doing some serious lawn restoration if you bomb chuncks from on high.
And the following is the best advice yet... When you bid these trees bid them high.... high enough that you can go out and buy the right equipment and hire an experience climber, and still make a sweet profit.... What are you charging for a days work???
Whatever it is, consider doubling it... You'd be surprised how doing good work and acting reliable will do more to build your business than low prices. High (good) prices allow you to do the job right, and they take a lot of the pressure off on any given job and therefore make the work much more enjoyable.
Good luck!!! Be safe!!!
God Bless,
Daniel
NebClimber wrote on 09-17-2003 09:11 AM:
Daniel:
I've posted a link to the two pines I am considering bidding. The link is at about the 18th post on the thread where I ask for removal advice. I've read a lot, and put to practice a lot of what I've read regarding how to make felling cuts. Also, I've come a long way in climbing with just my rope and harness. I have also limbed a lot of stuff out of trees using a natural crotch and lowering rope. The problem I have with the pines is that once I take all the limbs out, I don't know how to remove the remaining "telephone pole". I could just cut it in chunks and drop it a little at a time. I don't think that is a realistic option. I don't know anything about blocks. Even in theory, I don't understand how you can set up a block and pulley below the piece that is being cut b/c in my mind the piece would be free falling for a little bit until it passes/falls below the block/pulley point. Are there no low tech solutions? At least something I could implement on this first job so I can build from there?
Thanks,
Steven