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camaroman

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I dont know if this is that right place to put this and i have looked all over the internet but i still dont understand how to calcualte board feet in a log. i have found calcualtors on the interent but i dont understand the thickness of the board thing...say i have a 32" diameter log 10ft long..how many board feet are in that log? could someone please help me understand this..thanks, Nick
 
Scale from the small end, measuring the diameter inside the bark. The document Randy linked you to is a very good introduction to log scaling.
 
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If you are as math challenged as I am, I suggest buying a cheap, folding log rule that will do the math for you . You will have to choose which scale to get and that depends on who you plan to market the logs to . Doyle - international, scribner . A quick google should point you in the right direction .
 
Buy a scaling stick. Any good lumber store has them.
Check the log on the small end, allow 1/2" less than true diameter and read it from there.
Then deduct about 15% from what your stick says, because that's how it'll be scaled at the mill.
And don't get me started on grading logs.
 
Another useful tip:

bf/12 = cf

and

cf/128 = cords

The amount of board feet divided by 12 does not equal cubic feet. A board foot is not 1/12th a cubic foot. This is a common mistake, board foot rules have kerf allowances that were designed for mills of a century ago. In reality you will get somewhere between 4 to 8 bf per cubic foot. The cf/128 = cords is a correct conversion.
 
The amount of board feet divided by 12 does not equal cubic feet. A board foot is not 1/12th a cubic foot. This is a common mistake, board foot rules have kerf allowances that were designed for mills of a century ago. In reality you will get somewhere between 4 to 8 bf per cubic foot. The cf/128 = cords is a correct conversion.

By the definition that a bf is 12"x12"x1", a stack of a dozen bf is a cubic foot. Kerf is not calculated for in this estimate. Cubic feet are really only useful for converting bf to cords, so the kerf allowances are very different. I understand your point, but I'm not gonna estimate that I lose half of every log to sawdust before I ever put a log on the ground, even if the mill cuts it that way in the end.
 
By the definition that a bf is 12"x12"x1", a stack of a dozen bf is a cubic foot. Kerf is not calculated for in this estimate. Cubic feet are really only useful for converting bf to cords, so the kerf allowances are very different. I understand your point, but I'm not gonna estimate that I lose half of every log to sawdust before I ever put a log on the ground, even if the mill cuts it that way in the end.

You would not believe the amount of volume lost to slabs and edgings and grade trims, before you even figure kerf.
it is not 50% but it is substantial and should be considered at every layer.
 
I don't disagree; I'm just saying that, rather than the field, deductions due to kerf and hidden defect and taper are calculated in the office, and on the landing, and in the mill. Estimating the volume of a simple cylinder in the field is not rocket science. Even after deductions for sweep, disease, forks, etc, it's still a log-by-log estimate of simple cylinders, and the rest of the details fall out in the statistics.
 
ok thank you everyone for your help..i will do some reading up and try and figure it out....im not to handy on the math side of things :/ ...thanks again
 
By the definition that a bf is 12"x12"x1", a stack of a dozen bf is a cubic foot. Kerf is not calculated for in this estimate. Cubic feet are really only useful for converting bf to cords, so the kerf allowances are very different. I understand your point, but I'm not gonna estimate that I lose half of every log to sawdust before I ever put a log on the ground, even if the mill cuts it that way in the end.


Like I said earlier it's a common mistake, don't feel bad. The board foot scaling system is severely outdated, which is why a lot of mills still use it. The reason mills still use this system is take advantage of sellers who don't understand how this scale works. There have been over 100 different board foot log rules. A few of them are still very common today such as scribner, doyle and international. The relationship between bd ft and cubic foot changes with diameter of the log.

You don't just lose wood to the kerf, you also lose it to slab wood as well. Board foot rules don't account for slab wood, even though most every mill makes lumber out of it. The amount of lumber produced from the slab wood is called over-run. The amount of over-run varies with the log length and taper.

Remember that rough 4 to 8 board feet per cubic foot conversion doesn't account for losses from defect. Oh yeah and if you know about a kerf allowance for measuring in cords it's news to me, and probably the rest of the forest industry as well.

I don't disagree; I'm just saying that, rather than the field, deductions due to kerf and hidden defect and taper are calculated in the office, and on the landing, and in the mill. Estimating the volume of a simple cylinder in the field is not rocket science. Even after deductions for sweep, disease, forks, etc, it's still a log-by-log estimate of simple cylinders, and the rest of the details fall out in the statistics.

Remember the original question was about the board foot volume of the log, not the actual volume of the log. The board foot volume is an effort to try and tell you how many boards can be cut from a log. Which is why we call it board foot volume and not volume.
 
Remember the original question was about the board foot volume of the log, not the actual volume of the log.

Ah. I see the discrepancy here.

I'm a forestry technician -- a timber cruiser -- and I am only concerned with the standing volume of trees on a sale unit. What happens with them after they hit the ground is not part of my everyday duties. I am aware that cruised volume, marked volume, cut volume, scaled volume, and actual board-foot volume that makes it to Home Depot are all very different numbers. I am just one of many steps along the way.

Oh yeah and if you know about a kerf allowance for measuring in cords it's news to me, and probably the rest of the forest industry as well.

Not an allowance, really, just the observation that saw chips on the ground add up pretty quickly. My eye says it's about 5% of a 12" diameter log cut to 18" lengths.
 
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