estimating weight

[geofore]

I looked at a maple tree (silver), Circumferance 14' 9" at eye level, so lets say 5' ABH is close enough, that means 19.75 sqf. @ 50 lbs per cubic foot a ten foot stump ought to go close to 1,000 lbs per foot, 5 ton. Is there an easy way to figure out what it weighs? Does 50lbs per cubic foot green sound like it is enough for a maple or is it time to wait for the crane to weigh it? I tell the customer he doesn't want me to drop that or the first twenty feet of that tree next to his house, down his driveway, he needs the crane to lift it out of there. I'm telling him the first 20' of this stump is somewhere between 10 and 12 ton.

 

[rbtree]

geofore,

great estimate!

Here's a good site for all to use:

http://www.woodweb.com/cgi-bin/calculators/calc.pl?calculator=log_weight

It shows your log to weigh 9449 lb, based on 75% moisture content. But if you figure based on the circumference you gave, the weight drops to 8350 lb or so, likely a bit less as bark weighs less than wood.

The site has other calculators too, for log volume, etc.

 

[Stumper]

Your numbers are a bit high-45 lb per cubic foot is considered average for silver maple. In my area large silver maple are usually hollow-thus lighter per linear foot.. If the tree can be felled entire and allow the top to absorb shock I wouldn't worry. If it has to be pieced then you are talking some heavy pieces. The crane may be the way to go.

 

[Stumper]

Well, Roger "fastest fingers" Barnett beat me to it and posted a cool site to boot! Thanks RB.
Hmmm, thinking about some of the pieces I've loaded-Man I'm strong! Boy I'm dumb!

 

[geofore]

weight

Thanks for the sight info. The tree is not hollow, circumferance at the base is 16', eyelevel 14'9", at 12 feet it spreads out to 18' where it spreads out into four leaders. This makes me bet it is on the heavy side. On the north and west sides about 6' from the tree is a retaining wall 10' high on the west side and 7' high on the north side so it sits up on the hill a bit higher than one would think. I can imagine this tree going over in a wind storm and taking the wall with it and part of the the house next door. It already cost one garage a few years ago, and nearly a new car two weeks back when a limb landed in the nieghbor's driveway.
Everything has to go over the neighbor's driveway and two car garage or over the owners house to hit a safe landing zone. A crane is needed for that unless there is a secret to not putting it on the owner's bay window.
To just drop a large trunk is a good idea until the recoil takes out the retaining wall, it is the aftershock I worry about.

 

[Stumper]

Sounds like you have everything well analyzed and the safe method chosen -the crane. I hope that you get the job (if you want it) and get enough $ for it.

 

[rbtree]

Dang, one crew member awol, and the other feeling a bit low, guess we'll have to postpone today's work.

Boy, that is a biggie, geofore!! Sounds like a good day's work. hope you get the job, post pics, times and $, plus crane size and costs....

 

[rbtree]

I keep handy the wood weight calculation chart, similar to or same as the one in the Sherril catalog. I have also given a copy to Mike, the crane operator. That chart's figures vary by 0-15% from the website I posted.

Wood weights surely have variables... from spring to winter, from vigorous growing to declining, from tight grain to open, etc.
The largest discrepancy i've seen is with young sequoia or redwood. The website shows 37-42 lb per cubic foot, (75% moisture) but I have weighed it fresh cut and come up with appx 64 lb per cf! As much as oak or madrona...It is so full of water, it may be figured at 100%?!

 

[treeclimber165]

Geofore,
Keep in mind that all the charts discussed will show measurements in diameter, not circumference. I can't even picture what 14'9" circumference works out to in diameter. About 4'-5'?

 

[geofore]

estimate

The hour glass figure is 5' at the base 4'6" at eye level and 5'6" at 12' off the ground, diameter. Like my wife, a bit bigger on the top. The crane guy looked at it and said," WOW, that's a lot of tree." The stump grinder guy who advertises he does stumps for $85 asked how big around I thought it was and I said 16' and he hung up. He would be looking at 20' to get the root flare. The owner said at $3 an inch I could leave out the stump grinder, I called the $85 guy to get a good deal and he chocked. So much for truth in advertising.

 

[Nickrosis]

Funny - but

 

[rahtreelimbs]

Weight

I was out today to look over this tree with Geofore. This tree is everything he says it is. I'm hoping to do this tree with him. And as far as pictures are concerned, who cares. The info Geofore gave is right on the money. This guy has done his homework. Just looking at the tree and seeing what bases he covered was a learning experience. He is also opened to suggestions and listened to any opinions I had. If you need pictures for this thead, oh well. Use your imagination. Enough information was given.

 

[NickfromWI]

Circumference and diameter

To find out the diameter of a log when you know the circumference, just divide the circumference by pi, which is 3.14. To get a good estimate, it would be easier to just divide by three, and add a tiny bit!

Conversely, if you know the diameter, you can just multiply by 3 (or 3.14 to be exact) and BAM! --- there's your circumfrence.

Good stuff- we can use it every now and then on the job!

love
nick

 

[Nickrosis]

Re: Weight

Originally posted by rich hoffman
If you need pictures for this thead, oh well. Use your imagination. Enough information was given.

Come on, you know me. I'm very visually stimulated, and I do have a vivid imagination. I was just looking for an excuse to use that pictures.

Nickrosis

 

[John Paul Sanborn]

To get the weight of a cylinder you multiply the volume by the unit weight

the hight times the area of the median cross section or (Pi R Squared)*H

If D=5 then R=2.5 square that and

3.141592 (OK, my Dad was a Chemist...)
* 6.25
19.63495
* 10
196.3495 cuft
* 50
9817.475 LBS

So if you use 3 vice 3.14 you would end up with 9375 lbs or near a 1/4 ton off. have someone use a calculator.