Figuring out approx Bd Ft from Logs

Check out “how to do stuff.com; there’s a couple of methods, do whichever works best for you.

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http://www.forestry-suppliers.com/product_pages/View_Catalog_Page.asp?mi=1449

http://ohioline.osu.edu/for-fact/pdf/0062.pdf

http://msucares.com/pubs/publications/p1686.htm

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If you measure the diameter in inches at the butt and top, average them. OR Take the diameter in inches at breast height. Divide your diameter by 2 to get the radius. Multiply the radius x the radius x 3.14 = area of the circle x length in inches = volume in cubic inches divided by 144 = board feet in the tree. I’m sure there is some formula that allows for some waste, but I don’t know it. That is the basic math that will get you close.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence Wake Up America!! Please read; http://www.commondreams.org/view/2009/01/26-0

Do a google search for Doyle scale. You will find a chart that you can use to find BF in a log. You measure inside the bark on the small end and then need the length and it will show you the BF in the log and that is allowing for the saw cut.

Henry

-- alaskan79, Michigan

WOW!! That Doyle scale only gives about a third the bdft of calculating the mathamatical volume of a log.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence Wake Up America!! Please read; http://www.commondreams.org/view/2009/01/26-0

I use the Scribner scale

-- Dan, Sterling Alaska, Before you criticise some one, walk a mile in their shoes...then you will be a mile away and you have their shoes!

Print this off and keep it with you. It’s a chart I made, doyle scale. If you have larger logs than are on the chart go to the one 1/2 the diameter and take that times 4.6 (say you are looking at a 32” log use the number for 16” x 4.6, make sense ?) The chart is close enough for what you are trying to do.

-- http://nelsonwoodworks.biz/

Wow, that’s really useful Daren…

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very cool info from everyone – thanks for the links and tables

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I owned a hardwood sawmill in northern Wisconsin for 20 years. The Scribner Decimal C scale is the standard today. You measure on the small end under the bark. Also you must deduct for crook, sweep, and other defects. Here is a link for reference. If scaled and sawn correctly, you should relize at least 5-8% overun.

THEORY AND PRINCIPLES OF SCALING

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TopamaxSurvivor-You have to remember that you will have to take slabs off the log to get a cant and that is firewood. Plus the saw kerf. So you will not get out of the log what the true volume is. I have used the Doyle Scale on some of my logs I have milled and I get about 8% over what the chart says I should get.

Henry

-- alaskan79, Michigan

Henry, I thought there would be substanital waste, like maybe close to half, but not 2/3!! :-)

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence Wake Up America!! Please read; http://www.commondreams.org/view/2009/01/26-0

Henry, that is about my overrun too on the Doyle scale with my bandmill 5%-10%, depending on straightness/size etc. Around here we only use the Doyle scale.

-- http://nelsonwoodworks.biz/

TopamaxSurvivor here is the formula for Doyle:

(D-4)2 L
—————
16

(Small end diameter-4) squared then multiplied by the length of the log. Divide that number by 16.

Example 24”X8’ log:
24-4=20
20X20=400
400X8=3200
3200/16=200 bft

-- http://nelsonwoodworks.biz/

I think timber crusiers use breast height. Guess that is because they can’t get to the top.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence Wake Up America!! Please read; http://www.commondreams.org/view/2009/01/26-0