A friendly county commissioner, aware of my sawdust addiction called me yesterday. A tree had fallen on a small house - with the elderly lady resident inside. No, not to worry, miraculously, she wasn't hurt, but that tree put a hurtin' on the poor house. One of the broken roof rafters had punched down through the ceiling right over her bed and was protruding at least two feet downward. Yikes !
I was asked if I wanted the main trunk. (Of course, silly !)
I saw the damage today and was told an interesting detail:
When a crane was brought in to lift the 30-32" dia. Post Oak off the house, the weight on the boom was 47,000 pounds. A few limbs were trimmed, so as to make sure not to contact power lines, as the tree was gently relocated. After the trim, the weight was 45,000 lbs !
So, Saturday afternoon is taken : Firewood for my good friends and a whopper of a 22-25' trunk for me! Pictures to follow, if we're lucky.
Phil L.
Think maybe the calibration of their scale was a wee bit off? :o Perhaps they were picking up the whole house, too. :D :D
Are you sure that ain't a WATER oak? :o
Having operated a tree service formerly, with crane experience that figure is very realistic. I would have ball parked a 32" d.b.h. Oak tree at 58,500 lbs.
Green Oak is 66 lbs. a cubic foot.
At 66lbs a cubic foot a 25' long 32" log is 9200lbs the way I math it out, and that is with no taper. If it had been in the 50K lb range it would take a heck of a crane to lift and swing it if they cant get within 12-15 foot or so from it. I would guess the hole tree to be around 15K to 18K. :P
Andy
Got a stop doing math late at night, especially while dealing with a sinus cold infection. ::)
CORRECTION:
ADfields numbers are closer.
Allowing for some taper (25' log w/ 32"dbh) is apx. 120 cub. ft.
120 x 66 = 7920 lbs.
Doesn't the weight on the boom depend on the extension and degree of vertical that the boom is oriented?
Hmmm... The numbers don't quite add up, but the crane had to lift the entire tree, not just the log at the bottom. It would seem that there would be a considerable weight of upper trunk and limbs that aren't accounted for in the calculations. I wonder what it really weighed? (I really doubt 47,000, but I'm sure it was over 8000)
That size tree could weigh that easily. Look at these examples
http://www.treemoving.com/gallery.htm
I've operated cranes in the army for several years and for a local tree service for a fiew years after that.Although the tree was very heavy,and I'm not going to do the math,I would guess that these lower numbers were more accurate.
The gauge you were reading was most likely the pressure gauge for the boom lift cylinder reading the hyd. pressure in that cylinder in lbs. including boom,wire rope,hookblock,sling,and load.
I've seen operaters use this gauge to tell if they are overloading the crane,this is a dangerous practice,there are many other factors involved.This practice has resulted in two accidents in my area,becouse a tree guy needed a crane and bought one without any crane operating knowledge or training, using cranes in tree work is much more difficult then traditional crane operation.
I think I may have gotten side tracked a bit.
Thats just my guess.
Wes.
I hope you teach us some of the other things that are necessary to run a crane as you get more involved in the forum. I'm interested in how all that stuff works. :)
Jeff I checked out that web site,Ive always been interested in moving large trees,those root balls must be at least as heavy as the tree.[good site]
Wes.
This picture was on the front page of a past monthly newsletter my power company sends us. They are always preaching safety. I think there are several safety issues of the way the crane is being used, that must have escaped their editors.
(https://forestryforum.com/images/04_01_03/Bai%20Nimo%20crane.jpg)
Did NOT !
Did so !
Did NOT !
I think I might have created some corn-fusion here. When the crane did its thing, it was lifting the entire tree, not just the log. Now the limbs and top are all gone - poor thing is just lying there, waiting for Saturday afternoon's date with the Stihl 090 with a fresh chain!
The WoodWeb's log weight calculator:
Diameter - butt end = 33"
Diameter - small end = 29"
Log length = 25'
Est. log weight = 8,643 lbs.
I hope to get a fine 8' and a 12' section after lopping off some of the knotty area near the top.
I tend to wonder, also, whether the crane reading was the total boom stress, rather than actual load, but I didn't talk to the operator. Regardless, Mrs. Maddox has been involuntarily relocated. :(
Phil L.
Brian, I'm with you on that! Them look like magic tongs to me!! :o
Jeff, the trees on that link have a root ball of several yards of heavy wet earth to add to the mix. If I am the guy picking the tree off the house I would cut the stump off as soon as I had a good hold on the tree so as to not lift that part with it. Often blow down trees have snapped off not rolled over the root ball also.
Tom, a booms rating falls off very very fast when it's less then a 45 degree angle, and it's at it's strongest when vertical. This says the closer to the base the more it can pick up like you were thinking. Now say it's a 50 ton rated crane we are talking about, right? The folks that made that have rated it at it's strongest point, on a good hard flat place when all is wright with the world then build in a safety factor. Most of the time that puts the load inside the outriggers footprint and sometimes it's even over the body where it's not possible to lift from as you would be parked ontop of it. ;) It's all down hill from there the more you go out the less you can pick!
Hear is me MAXING out a 65ton wrecker crane with a 50,000lb (just 25 tons) pick down in Arizona before I moved to Alaska.
(https://forestryforum.com/images/04_01_03/P3290007_a2.jpg)
(https://forestryforum.com/images/04_01_03/P3290013_a2.jpg)
If you want to know about this kind of stuff I'm your man! ;D After over 20 years around it I learned a thing or two but there is still a lot yet to be known! :P
Andy
Phil, as I stated I would guess the hole tree to be around 15K to 18K. That's without the rootball on it, with the rootball and dirt I would double it. Have fun with it! ;D :) Sounds like you may get some great slabs from it! 8) 28" or 30" by 8' would make some cool stuff!! ;)
Andy
One mistake I made when trying to flip an oak stump out of the ground is about how much it weighted with the dirt and rocks. Once I started knocking wheelbarrows of clay and rocks out of it (literally - I held a wheel barrow under it) I started thinking about why I could not move it out of the hole.
6L x 6W x 4D = 144 cf x 60 pounds of clay and rock = 8640. That was not counting the stump 54w x 18h. I know I must have missed a six inch root somewhere when I was cutting the stump free. Which probably has considerable strength even when the tree ie ripped out of the ground. I imagine that would give a crane the fits and 1/2.
Yea, trees around the house are nice until the house is around them. You can imagine the sound it made as it snapped beams.
In the Atlanta GA area a few months ago, a mother and her two kids were killed in their SUV when a oak crushed it flat in their driveway. :-(
Week later another person was killed when a tree split (looked like oak on the news) in 1/2 and fell on a car passing by. Crushed the 80s Chevy fullsize car about a foot high cross the windshield. No skidmarks or travel after the limb hit, just squished flat like a bug.
Lady in that house was lucky not be killed or crippled.
My Dad was a wonder with a crane, my brother is still an operator. He says that they all come with computers now. The computer calculates all the angles etc. and tells you if you can make the lift. He says the only way to shut the forman up when he wants somethin' done that can't be, is just ask him for authorization to bypass the 'puter.
I've been wanting to post something about this tree
for a long time but had never found a good web site
about it till today. I had only seen it in a golfing magazine
Root ball and all 232+ tons.
http://www.golfcalifornia.com/departments/features/pebble-beach-tree.htm
O.K. First I owe Ron W an apology because I forgot to add OUR log weight calculator to the tool box, we only made a post about it and a link to it there.
https://forestryforum.com/calcs/log_weight.htm
You dont need to go anywhere else for calculators for wood. The originals are all here. We had the ideas, we made them and the best are still here.
I am going to make it a point to redo our toolbox so the calcs are easier to find, it includes all of them and they are intefreated (oops) integrated into the forestry forum.
original post about weight calc created by Ron W (https://forestryforum.com/cgi-bin/board/YaBB.pl?board=sawmill;action=display;num=1042765852;start#2)
Y'alls' is purtier than that one on that other forum ;D
When I operated for the tree company we didnt have a puter onboard we estamated weights from prior experience and stayed on the lite side,We were able to do all of our jobs with a 16 ton crane truck, when removing trees from houses we would pick it apart.
Phil, Does the stihl 090 have the chain adjuster on the side or in front of the powerhead? The only thing i dont like about my huskey 3120 is that the adjuster is in the front and you cant adjust the chain with the alaskin mill attached,wish I realised that before I bought it.
HAPPY SLABING ;D
PS it seems that you sawmill folks are knowledgeable in all fields 8) 8)
Excellent idea, Jeff,
That way I won't have my attention diverted away from what is the best wood site by far. Of course, I only jogged over there
long enough for the calculation
and then came back . . .
home, where I belong !
WES, the 090 is the same - on the front. Will Malloff's book shows how he improved the situation. He drilled a hole through the thrust skid on his Granberg, aligned with the tensioning screw. Haven't done it, but it sure would save some frustration, huh?
Phil L.
Jeff & Ron, if you're gonna be redoing the calculators anyway, could you add one little feature? It would be nice if they told what increments the result is stated in, such as bf, cu ft, etc.
It's sorta obvious sometimes, but other times I have to actually THINK, which isn't something I do well. ??? ::) :-/
I think they all do that DanG, something in particular you can point out?
I think it was the log volume calculator I was using. On the small logs, I was unsure if we were talking board feet or cubic feet.
Log volume output in doyle scribner and international would be Board foot. Only time a volume is cubic ft is when we state that it is.
QuoteDoesn't the weight on the boom depend on the extension and degree of vertical that the boom is oriented?
Tom, if I'm right, the weight doesn't change unless you change gravity (take the tree to the moon..)- but the torque on the boom will definitely change depending how the tree is rigged. lw
LW,
That's what a guy might think at first -------a log's weight stays the same regardless of the length of the pole that picks it up etc. That Eienstein feller claimed that if you make something travel real fast, it changes it's size or weight or somethin. I'm pretty dubious of that one too. Just how the heck ya gonna weigh or measure something going so fast ya can't see it?
I do know for a fact that you can catch a 10 pound punkinseed on a fly rod and retrieve it in a dip net and the weight shrinks to almost nothing :-/
Yeah, I know you're right LW. I misappropriated my definition. :D It's apparent weight that was my concern and you are right, that is properly defined as torque. What was coming to mind was the 9.5 pound M-1 that my drill sargent had me hold at arms length until I could no longer hold it there. I could still hold it next to my body so my mind told me it was heavier out there at the end of my extended arms. If I could have convinced myself that it weighed only 9.5 lbs in either place I would have been the Hero of the company because I could have held it extended for a lo-o-ong time. :D :D You cause all kinds of problems at the end of the lever when you move the fulcrum :P
I'm going to bring some gravity home with me one day and test this ::) :-/ :P ;D
LW,
The weight on the boom is the weight of the load,sling and hookblock,That doesnt change during operation.However the weight on the boom hoist cylinder does change during operation as you stated,with the boom length and boom angle.
Wes.
Here are some pictures of the offending Post Oak and its victim. They are courtesy of Ernie Hibbert, who likes to watch me do stupid things, such as cut up trees with a chainsaw mill. Hope to add a couple more shots of the crunched house later.
Phil L.
GET READY
(https://forestryforum.com/images/04_01_03/ffwebAA.jpg)
GET SET
(https://forestryforum.com/images/04_01_03/ffwebAB.jpg)
GO
(https://forestryforum.com/images/04_01_03/ffwebAC.jpg)
FINALLY READY TO COOK!
(https://forestryforum.com/images/04_01_03/ffwebAD.jpg)
neat, i know how often people rip with chain saws, i just have never seen it.
Thats a cool feed system you have! ;) You just lag it to the end of the log? What do you do when you get the saw to the end with the ropes?
Andy
Hey Andy!
In the first photo you may have noticed a DeWalt rechargeable in my right hand. I was screwing the "yoke" to the end of the log, placing it below the level of the cut. When I got near the end of the log, I moved the wench with its spiked base to the nearby stump and kept cranking from there. The alternative to this stump trick is to bump the wench assembly free, lay it aside, and push the saw the rest of the way through the cut by hand. Pushing is tough on a tree like this, especially when making a 13" thick cut. (Post Oak is a demanding species.) The Granberg frame wants to rack; it gets ahead of where the saw is and tends to bind. In addition, the bark of Post Oak is thick and deeply fissured, causing the thrust skids on the mill frame to fight with you. Much better to pull at the bar level as does this wench idea. This cut ran from 27" to about 30"
Special thanks to the book, Chainsaw Lumber Making by Will Malloff. He loved lags. I love big deck screws. Excepting that detail, the yoke and wench assembly are direct copies of the design presented in the book. The Era detergent container caddy and dispenser system was my "cheapskate" idea. It just sits there for the ride, sending a stream of water and Pine Sol. ;D
Phil L.