Log Weight Calculating

[charles mann]

Ok, i have several logs scaling and weighing apps, and i was trying to get a ball park estimated wt. of some pines, exact species, unk, but it seems long, short leaf and lob, weigh close (+/- a few lbs per cubic feet). Iv been using log weight pro, but just downloaded log climber and there is quite a bit of variation between the 2 apps, plus what i can find on google. log weight pro says long leaf weighs around 68 lbs/ft3 (i would assume when the sap is at its peak); log climber says 32.5 lbs/ft3, which lines up with what google says for dry wt., but looking at google for wet, on several forestry links, it seems 37 lbs/ft3 is the avg. and close. But going off previous logs, using both apps, plus my tractor with 3000 lbs of lift, and not being able to pick/curl some of the logs, the wt. is somewhere in between the two apps. but after scaling the load at the CAT scales, and coming up with 2-4k lbs liter than what log wt. pro says, but 2-4k heavier than log climber, i can only split the difference and go from there. 

Which is right, wrong or close? I could go off log wt. pro to be on the "safe" side as to not overload myself. But a 3-4hr drive 1 way with a lite load seems a waste in time and fuel. Id like to maximize my hauls. If i lived local, i wouldn't care, but an 8hr day of driving and around 6-8 hrs felling, bucking and loading a lite load, makes for a wasted day. Beings that i have a cdl, i cant play the stupid game and claim "oh, i thought 24k meant 24k of load, not gross". 

Any help out there with an app, or an old tried and true method of wt. scaling? 

[rusticretreater]

If the app doesn't know the moisture content of each log, it can't give you a more accurate estimate of its weight.  So everything is a guess.  You have found part of your solution I think.  You know the high and the low weights of the wood by using the apps.

The other part is knowing the moisture content of your logs and adjusting your weight total accordingly.  If the trees are all felled at the same time and the logs bucked at the same time, three or four moisture readings will give you a number to use to find the right weight per cubic foot.

Some math:

Max weight ft3   maxw
Min weight ft3    minw

Max moisture    maxm
Min moisture     minm

(maxw - minw) / (maxm - minm) = lbs per %of moisture

weight per ft3 = minw + (( lbs per %of moisture x moisture% above minimum)

example
maxw = 68 ft3
minw = 32 ft3
maxm = 30% or 30
minm = 12% or 12

moisture reading from log = 27%

(68 - 32 / (30 - 12) =  lbs per %of moisture
36 / 18 = 2  lbs per %of moisture

moisture% above minimum = 27% - 12% = 15

weight per ft3 = 32 +( 2 x 15)
weight per ft3  = 32 + 30   or 62 lbs per ft3
------------------------

The only way to know if this works is to do the calcs and then take the wood to be weighed.  You could then make up a worksheet with the formulas and keep with with some charts or use your apps to get numbers to punch into the equations.

[charles mann]

So the days before onboard tck scales and hand held moisture meters was kind more what i was looking for. 
I don't own, but really need to buy one, a moisture meter, so without the meter, that formula wouldn't do much good. Once i buy a meter, sure, that would work, and like you said, build a spread sheet (someone smarter than me to input the formulas into excel) and it should provide a close total wt. per log. 
I have a couple tech savvy co-workers that should be able to create spread sheet with the formula you provided and see how well it works.

I know the MC is a changing variable throughout the season and there is NO constant, dead set answer. I might just have to use both apps and split the difference, but the spreadsheet would come in handy when it comes time to buy logs from a logger or land owner without having to go across the scales and come back with a scale receipt. Thats until the in-home finance lady approves the purchase of a self loading tck/tlr and either get scales for it or a load cell at the grapple head.  

[rusticretreater]

So the days before onboard tck scales and hand held moisture meters was kind more what i was looking for.

Those are the days where you lived by your wits and dickered with the guy on the log dock for a price.  Experience ruled.

[GAB]

I question the 68#/CF for pine.
In VT pine logs float and since the density of water is 62.4#/CF that means that the logs would not float.
GAB

[beenthere]

The tables only can give an estimate. A lot of factors that cannot be measured enter into that estimate. 

[charles mann]

I question the 68#/CF for pine.
In VT pine logs float and since the density of water is 62.4#/CF that means that the logs would not float.
GAB

Nvr thought of it that way. But you are correct, the logs would just sink. Which i can test that sat of nxt wk. if a 16'x28" log floats, its definitely liter than my pond water. I guess i'll go with the info found online from some forestry document of 37#/cf and haul them across the scales. 
As you said beenthere, numerous variables to account for for an exact. But dang, there has to be something better than 2x+/- difference between the 2 apps. 

[Erik A]

Consider... if the log is just barely out of the water then its close to 64 as it rises up it is less dense. You may be able to check with a dry piece, weigh it then see how it rides in the water. I would thunk if it is in the 37# range you should have half of it out of the water?  

I have no log floating experience to back this up, but i have done similar with rocks!

[Ianab]

Metric does make things easier. Fresh water has a SG of 1. As in one cubic meter of water weighs 1,000 kg or 1 ton. If your wood has a SG of 0.95, then it's going to float (just). But the existence of "sinker logs" proves that some wood has a SG more than 1.  

Local pine has a SG of 0.4 - 0.5 depending on how dry it is. So of course it floats. Some of the Aussie and tropical hardwoods have a SG of 1.1 or more. Not much use for building a raft.  :D

[charles mann]

I dont know crap about metric except that i have to have double the tools to work on crap. I do my best to avoid converting american to metric or vise versa. Ill stick to american numbers.  ;D

[GAB]

A millimeter is .039370078 inches.
For quick math 40 thousands of an inch/mm.
So 8mm is roughly .320 inches.
GAB

[rusticretreater]

I keep several laminated conversion charts around the workshop and in my toolbox.

[charles mann]

If i abosultely have to deal in metric, i have an app that converts american to metric, along with many other conversions. For nearly 50 yrs iv been using standard measurements and refuse to switch to metric. 
The acft i work on is built to standard measurements, our repair and inspection criteria is standard. I fabricate wood and metal in standard. Hopefully im long dead before everything in the usa is switched to metric. I dont care how simple some people say it is to use bc everything is a factor of 10. Iv spent over half my life using/building with standard, i'll keep using it. 
If i grew up learning both, that would be one thing, but i didnt and have zero care to start now. 

[doc henderson]

you can just ask Siri and she will convert it with an English accent on my phone.   smiley_gorgeous

[charles mann]

you can just ask Siri and she will convert it with an English accent on my phone.   smiley_gorgeous

She is deactivated on my electronics. These devises spy on us enough, i dont want another listening devise on my phone. 
Either way, i could care less in using metric when it comes to most of my life tasks, esp when it comes to a formula to calculate log weight. 
My opinions about the metric system, if spoken, would get me banned

[GAB]

I've had to work with it, and I agree with you.
GAB

[barbender]

 In Minnesota, red pine is our heaviest pine when green. The local stud mill buys it on weight, and converts it at 4800 pounds per cord. 

 Any of the southern yellow pines are much heavier. I think I remember a number of 5500 pounds per cord? There will always be some variance, but usually within a couple hundred pounds plus or minus with fresh cut logs. 

 I've not really seen reliable numbers for fresh cut logs on the web on any of the the charts, and even our toolbox gives numbers that are off for the species that I am familiar with. 

 What length are the logs you are cutting, Charles? You could scale them, I would use the international scale. There are roughly 2 cords per 1000 board feet of logs, or said another way your pine logs should be around 11,000 pounds per 1000bf if they are fairly fresh. 

 PS I love metric😁

[Jeff]

Our log weight calculator disclaimer.

  This calculator is useful in providing approximate weights for species, but the user should be careful in how the product is used. Wood varies considerably in weight per constant volume (density) on a regional level and at the local level. That is, the weight of a piece of wood from one area or tree will differ from the same species in the another area. The growth rate is the most significant factor in determining density, with slower growing trees having a higher density (therefore greater weight), than faster growing trees. This is due to the late wood cells (the dark ring seen when a tree is cut) having thicker walls and being closer together than the early wood (lighter wood between the rings).
     Where the board is cut from the tree is another factor, the heartwood portion of the tree (the center portion, often characterized by a change in colour) is composed of dead cells and will be lighter than the sap wood, where the cells are still living. Wood that is cut from the portion of the stem that still has live branches on it will be lighter due to hormones produced by the foliage.

     In different areas, genetics will play a factor in wood density, along with the growing site (moisture and nutrient characteristics of the soil). Where the tree grows on the hillside, eg south facing versus north facing slope, high elevation versus low elevation, areas of heavy snowpack versus light snowpack, constant winds versus sheltered locations all have an influence on the density of wood.

[barbender]

I have been on jobs where I was loading trucks with black spruce. The wood is very uniform in size. Putting the same size load on (the stakes had marks) the loads were varying sometimes by 5000 pounds. That was due to just varying moisture contents in the wood from various areas on the sale.

[charles mann]

@barbender 
16' here recently has been my needed size. But since im not cutting firewood, cord weights dont help to much. But the BF x wt. does. 
This last trip, i used the log weight pro, measured the small end and round up to the nearest inch if it was 1/2" or greater and down if it was less than 1/2". I came in 200 lbs under what the cat scales ticket said, coming in at 18,000 lbs. 
i guess i'll try that again and see how close i get, and once more for good measures. If im consistently averaging around 300 or less, i'll call it close enough. Im hoping to squeeze another 2000 lbs out to round me up to 10 tons per trip IF there is that much to be had. 

[barbender]

The only reason I mentioned cords, is that the only readily available green weights of round wood I've seen are in cords. Just average 2 cords pre 1000 board feet of logs and you'll be close. Sounds like you're getting it dialed in, anyhow👍