Spider leg removal

[murphy4trees]

We managed to salvage a nice job out of a very wet day and have some fun too!
The job was to remove 8 small-medium wild cherry trees... The customer is a landscape gardener, specializing in perrenials.. In the pic here, we set up a floating block (pulley) to lower from in the large Tulip to the right.. lowerring device at base.
Ladder is in the cherry to be removed. The idea was to use a spider leg on the lowerring line to float most of the cherry trees over the perrenials, which worked well... For this tree though we need to see-saw the cherry right over that nice little Jap Maple between the cherry and the Tulip. Which took a little extra thinking.

 

[murphy4trees]

I used a handsaw to remove several lower limbs so they wouldn't catch on Jap Maple... The spider leg is tied and set, though difficulty to see cause it blends in to backround... In the future I will make an effort to use a bright color line for the spider leg.

 

[murphy4trees]

Double tied in (also hard to see), notch is set and I Am ready to cut.

 

[murphy4trees]

Piece is away.... notice I adjusted the spider leg to allow the tip to drop, bringing the but up as it gently glided past Jap Maple....
Zero damage to maple and below plantings.

 

[murphy4trees]

A reverse angle of last pic showing piece suspended under Tulip, over lawn.

 

[murphy4trees]

Here's a closer shot of the spider leg... It was fun to watch those trees float gracefully into the yard... customer thought it was cool too.... and cooked us some burgers.

 

[rbtree]

Very very nice and slick, murph!!! Thanks for showing us (and this old dog) a new trick!

Personally, tho, I'd be in my gaffs, as that size tree is easy for me to stand in. But, unlike many folks, I use my 28 foot ladder, and orchard ladder a lot.

 

[ramanujan]

speaking of floating trees... we removed two firs trees today with aid of a crane. both trees were approx. 110'. client was very opposed to any of her flowers/shrubs in her back yard being damaged in the least and was sure that the trees could not be removed without something being killed.

3 picks each for each tree and 2.5 hours and the trees were gone and nary a leaf was torn. the work that the crane saved us was staggering. the job also made me realize again just how smoothly difficult jobs can go if everyone on the site is competent, experienced and communicative.

 

[TheTreeSpyder]

That is pretty darn creative thinkin'!

When wee are gonna speedline, i tell the brush pilots to get the 'gravity bender'; and also miss-name a Porty as 'Rope-Brake' (no not break!); to give descriptive terms to what we are doing.

Sumthin'bout the term 'spider leg removal';.....makes my hip hurt!

 

[Kneejerk Bombas]

Good work as usual, of course, who's going to show pictures of the jobs they messed up?

As I looked at the pictures, I noticed the spider leg was adjusted so the limb would tip over, and I thought, "Oh no, he has the spider leg adjusted wrong." But you made it work anyway.
I would have thought that you would want the tree to stay upright and have as little movement as possible.

I also noticed that there was no way to get any lift. Perhaps a block and tackle piggy backed on the bull rope could have been helpful, especially on the next piece so you could lift it out of the brush.

 

[rbtree]

Mike,

I think you are missing the point of Rob's actions. As the gin pole was set to the side, a high single tie point would have allowed the tree to drop right into the maple. But the way he brilliantly calculated the tie points allowed the center of balance of the tree to drop the right amount...as the tip dropped more and the butt swung up to clear the maple.....sweet.

If he had attempted to lift the entire tree up, a back line would have been required to hold the tree back. And it would have have to be placed in the correct location so as to not endanger Rob....otherwise the butt would have to be snubbed with a third line...now we'd have an awful lot of rigging time for such a small tree.

 

[murphy4trees]

Part of the beauty of that job was its simplicity.... Why go to the time and energy needed for fancy rigging when gravity will do most of the work. (To answer my own rhetorical question.. "cause I haven't broken down and dropped a quarter on the GRCS yet)

The pulley was set about 65' high in a Tulip crotch, 4-5' out from the trunk with safety blue (7700 lb. fairly dynamic line). The lowering line was 1/2" double braid 10,000 lb static... The object was to reduce as much stretch in the line as possible... I was concerned with the force multipliers and yet was certain the big Tulip could handle the added force as we were working with fairly light wieghts, no more than ~400 lbs. 400x4=1600... the overhead anchor could handle 1600 easily, though that well exceeds the 10% SWL of the safety blue.. EDIT8/8/03: actually in re-thinking these forces the safety blue would only be holding 800 lb. (on each leg), so though the OA has to hold 1600, we were still working with acceptable loads on the lines.

We pre-tightenned the lines with two men pulling and one man taking slack out at the Porty. The beauty of this system is that it uses the weight above the CoB to lift the butt. The first four went like that.. the next two were just too far away from the Tulip to use the Spider Leg, but they were small enough that when tip-tied (above the CoB) and cut from the ground, one man was able to catch the butts and carry them out to the lawn.

We have plenty of block and tackle and a rope come-along etc. And none was needed. Though I did have to strap on the hooks and lower pieces on the last cherry, which was behind the shed...

That's a Werner 24' ladder, extended to 15'. I had had it fully extended earlier and still used a pole saw to set the spider leg. To me that's a lot easier than using the hooks. I had also used the ladder for setting lines in the previous three trees, which were cut from the ground.
As Mike rightly pointed out... they don't all work like that, though when they do, it keeps me coming back for more....

 

[TheTreeSpyder]

i really like the self werking systems like that, especially building beyond spyder leg (ouch!), plotting the soft end heavy, but long enough to reach over obstacle; then at tearoff that heavy end keeps the butt from hitting obstacle. Doesn't spyder leg just make C.o.B. calculation more forgiving? Whereby, if ya can calculate 60/40 w/soft end heavy, more forgiving if something goes a lil wrong; and 60/40 not as hard or picky to get in the 1st class lever position as 50/50 from 1 balance point. Also soft end heavy, allows it to tip down, and then no violent reversal of changing of low end at tearoff?

GRC$ would be great, but if ya ain't got it, and can get that self werking float.........

i'll be bold enough to say, i might have tried to use speedline laced thru 3/1 tightner off/ or around trunk/anchor , then locked off around trunk each load? And, what if ya switched the 2 lines around, using more static double braid as speedline/ gravity bender and the more dynamic line for lowering on that 'trolley'/speedline/gravity bender? Or did i get that right?

Or, something like that.....

 

[rbtree]

Sorry Dan, I forgot and called you Rob, the feller a couple hemispheres away!!


One correction, though... Our lifelines are definitely not dynamic ropes!!! If you go to the Samson catalog, referenced recently by someone here, it will give you the properties of the Arbormaster lines...which just happen to have about half the stretch of my NE Ropes "true" static line.