Determining Board Ft from Forest

[jfynyson]

This Fall before the leaves are gone I want to take inventory of my woods that'll be cleared in a couple years for building a house & workshop. I'd like to pick the best looking white oaks, maples, etc. that I'd like to have milled up for lumber and am trying to find the easiest/cheapest way to roughly determine how many ~8-10ft logs I will get from what all species.

I was planning on buying a Doyle Scale Log Rule/Stick but I'm being cheap here and not wishing to spend $50 on one of those (after shipping) for just a few trees. Does anyone know another way to roughly calculate this using maybe a yard stick held at a specific distance ? I believe if I thought through the math I could figure it out but hoping someone has an easier way or already has it figured out that they'd be willing to share. I have the Doyle Log Rule Scale sheet detailing board ft from tree log length & diameter so just need to get tree height and diameter (of course could use measuring tape for diameter).

Thanks in advance

 

[wbarnes]

I saw this video a while ago and thought it was interesting. Maybe it’ll help…

 

[Oka]

Look up Scribner 's. Logging scaling book. There is also one you can download from Oregon University. I posted the link a few months ago.
One simple thing to remember. A 16" dia log 16' long is about 100 bd ft

 

[walnutjerry]

This Fall before the leaves are gone I want to take inventory of my woods that'll be cleared in a couple years for building a house & workshop. I'd like to pick the best looking white oaks, maples, etc. that I'd like to have milled up for lumber and am trying to find the easiest/cheapest way to roughly determine how many ~8-10ft logs I will get from what all species.

I was planning on buying a Doyle Scale Log Rule/Stick but I'm being cheap here and not wishing to spend $50 on one of those (after shipping) for just a few trees. Does anyone know another way to roughly calculate this using maybe a yard stick held at a specific distance ? I believe if I thought through the math I could figure it out but hoping someone has an easier way or already has it figured out that they'd be willing to share. I have the Doyle Log Rule Scale sheet detailing board ft from tree log length & diameter so just need to get tree height and diameter (of course could use measuring tape for diameter).

Thanks in advance

Call a forester----------pending how many acres you have, you may get it measured for free.

 

[RobS.]

I'm pretty sure I still have a couple of those (Biltmore) sticks out in my barn. I also have a table for estimating bf volume of timber published by the USDA Forest Service and a tally book and a couple tally cards for cruising timber. The table has volumes in Doyle, Scribner and International log rule. I used to work in the woods cruising timber. These are free to you if you want them/have some way to get them.

A forester will charge you a fee or forgo the fee for a commission if he sells the timber for you.

 

[jfynyson]

Thank you all !

I'm pretty sure I still have a couple of those (Biltmore) sticks out in my barn. I also have a table for estimating bf volume of timber published by the USDA Forest Service and a tally book and a couple tally cards for cruising timber. The table has volumes in Doyle, Scribner and International log rule. I used to work in the woods cruising timber. These are free to you if you want them/have some way to get them.

A forester will charge you a fee or forgo the fee for a commission if he sells the timber for you.

Many thanks for the offer. Where are you located (feel free to PM me if you'd rather not say here) ?

 

[RobS.]

I live 2 1/2 miles south of Spring Hope on highway 581 (27882). That's about 30 miles east of Raleigh, 20 miles west of Rocky Mount just off of highway 64 in Nash County.
I'll go out to the barn shortly and see if I can find where I put them.

 

[jfynyson]

I live 2 1/2 miles south of Spring Hope on highway 581 (27882). That's about 30 miles east of Raleigh, 20 miles west of Rocky Mount just off of highway 64 in Nash County.
I'll go out to the barn shortly and see if I can find where I put them.

Dang, no worries. I'm 2hrs drive from you (one way). Thanks anyhow !

 

[marinosr]

As far as determining height, you can use your woodworking bevel gauge with something heavy hung off of the metal piece. Stand back a fixed distance x you can measure from the tree, 10 ft is good if you just want to measure up the trunk to the merchantable height. Let the metal part of the bevel gauge swing freely while you sight up the wood part of the bevel gauge to the point you want to measure on the tree. Once you have the spot sighted, lock the bevel gauge into place and measure the angle, a. The height of the point you sighted to will be x/tan(a) +h, where h is your height, measured to your eye. Subtract one foot for stumpage. Not 100% convenient, but it is free.

 

[RobS.]

I looked for the sticks, then I looked again, then I looked some more and found them in the first place I looked. They were between some old yardsticks right where I thought they were but wedged behind the yardsticks.

They are in international scale which is the in the volume book.

Maybe pony express? If not, this stuff is free if anyone else wants it. It's been 30 years since I worked in the woods. Probably couldn't do it now even if I wanted to.

 

[jfynyson]

As far as determining height, you can use your woodworking bevel gauge with something heavy hung off of the metal piece. Stand back a fixed distance x you can measure from the tree, 10 ft is good if you just want to measure up the trunk to the merchantable height. Let the metal part of the bevel gauge swing freely while you sight up the wood part of the bevel gauge to the point you want to measure on the tree. Once you have the spot sighted, lock the bevel gauge into place and measure the angle, a. The height of the point you sighted to will be x*tan(a) +h, where h is your height, measured to your eye. Subtract one foot for stumpage. Not 100% convenient, but it is free.

Sounds easy & interesting but sorry, I'm not just understanding / visualizing this methodology exactly. Are there pics or a video for reference ?

 

[marinosr]

Whoops, I had the formula wrong in my initial post. I've corrected it, and in the doodle below. Does the pic below make it click?

 

[jfynyson]

Gotcha, I was missing something. If standing 10ft back (set as "x") and randomly assuming the bevel angle (set as "a") is 35 degrees (I do not have a protractor so guessing for this example) and assuming the height to my eye is 5.5ft then the resulting height of the logs made no sense.

I was getting 10ft/tan(35 degrees)+5.5ft = 1.67 OR is using inches 120"/tan(35)+66 = 1.81

Depended how I enter it in my calculator. Typically I'd break up the equation getting tan(35) then adding 5.5ft then 10 divided by that sum but by simply not breaking up the equation on the calculator and say 10/tan(35)+5.5 straight through I get 26.6...assuming that's a 26.6ft log section.

 

[wbarnes]

Shouldn’t the equation be x*tan(a)+h?

That would give about 12.5’.

 

[marinosr]

Jeremy: Your calculator is in radians mode, not degrees mode, when doing the tangent. I got your incorrect answer, 26.6, if I did the calculation with an angle measurement of 35 radians. Using an angle measurement of 34 degrees, the correct answer is 19.78. You can also ask Google to do it for you.

The way one could enter it on a calculator, if using a basic calculator, is:
35
tan
1/x (to put the result it in the denominator)
X (multiplication)
10
+
5.5

Note that the angle you're getting off the bevel gauge is the angle betweeen the sighted line and VERTICAL, not the sighted line and horizontal. It's equal to the angle between the sighted line and the trunk, as indicated in the diagram by the two blue angle markings. Given that, I'd say the angle of interest in the picture above is closer to 60, not 35.

For that corner of the triangle, tan(a) = horizontal/vertical, so vertical = horizontal/tan(a), which is what I put in the formula.

 

[emichael]

I looked for the sticks, then I looked again, then I looked some more and found them in the first place I looked. They were between some old yardsticks right where I thought they were but wedged behind the yardsticks.

They are in international scale which is the in the volume book.

Maybe pony express? If not, this stuff is free if anyone else wants it. It's been 30 years since I worked in the woods. Probably couldn't do it now even if I wanted to.

I haven't used my Biltmore stick since the late 80s. This thread made me dig it out. Looking it over I"m not sure I remember how it works. Use it or lose it!