'scuse me - a little explanation please?

[sigidi]

Ok, using the magnificent resources of the Forum, and trying to make life easier :D

I've been looking at the board foot calculator-tree and need a bit of explainin please!!
now being from over the sea, I understand the concept of DBH, also bft and can convert bft into cubic metres easily enough.

Where I come unstuck is with form/taper and Doyle, Scribner and international. Now from reading various stuff here on the forum, I have heard one should buy on one scale and sell on the other scale.

What I am interested in, is getting an accurate estimate of what is in a standing tree. in the example of needing 5 cubic metres of cut timber, using a recovery of 40%, this then gives a required log volume of 12.5 cubes or 5300 bft of tree to be felled to yield what I am looking for (the last thing I want to do is tell someone to put down say 18 trees, when we use only 14)

I know I may be asking a lot, and understand it is an estimate rather than formula for linear velocity from physics, but if I can get some info on the above, then it will give me somewhere to start.

TIA

[Ron Wenrich]

Form class relates to the amount of taper in a tree.  It is the relationship of the dbh and the diameter inside bark (dib) at 17', which is the end of the first log.  That taper will vary due to bark thickness and the amount of taper in the tree.  Taper normally gets to be less in older trees.

But, the best you will ever get is an estimate.  Normally, there is an overrun from tree volume to log volume and from log volume to sawn volume.  Your recovery would also be dependent on what you are cutting.  The bigger the stock, the better the lumber recovery factor (LRF).  The LRF will also vary with the size of logs you are working with.  The smaller the logs, the lower the LRF.

Maybe you want to try this calculator:  http://www.timberbuyer.net/pulp.htm  Its our pulpwood calculator and  I don't see it on our calculator list.  It does give yield in cubic meters.  It may be easier for you to use.  It doesn't have a Form Class and your input diameter would be in inches, not cm.

[sigidi]

Ok Ron,

so with the new calculator it'll give a log-cube volume? Does it make any difference that I am not pulping the log?
IS BOLT LENGTH how long the bucked log would be?
Is this calculator specific ro hardwoods or softwoods, or is it an average figure for the timbers mentioned below it?

I know I am asking a bunch of Q's, but remembering back many moons to my educating days, any formula/calculator is only as good as how you use it - hence all the q's

Thanks for your help Ron.

Another Q - the Forum calculator, does that give results in board foot using doyle, Scribner and international?

[Ron Wenrich]

The bolt length is how long you cut your pulpwood logs.  It is only a measuring method for height.  I would use the 8' bolt and consider that a 1/2 log.

When scaling timber, you use the dbh and the number of 16' logs in a tree.  You can use from 1 log to 5 logs using 1/2 log increments. 

The pulpwood calculator isn't species specific when it comes to a volume measurement, like you want.  If you are looking at weight, then the hardwood and softwood issue comes about.

The forum tree calculator gives the volume in board feet.  Anytime you see a scale like doyle, scribner, etc, it is always used with board feet.  Rarely do you see cubic foot measure and we decided against the metric system 25 years ago.  I guess we figured the world would follow our lead.   :D

[sigidi]

So Ron,

I noticed when using the Forum calculator that there is a big difference between Doyle, Scribner and International for an example 19" log.

To try and get a best 'guess' of bft (cubic metres) out of a standing hardwood, to then choose how many tree's to put down for a specific project am I better using the Doyle results as they are the smallest given the example, or will that give me too much room for error. Or should I use the pulpwood calculator you mentioned and then use my recovery figures for those species and apply it to the volume results from the pulpwood calculator?

I know it's a "peice of string" kind of question but I just don't wnat to put good tree's down and they not be needed. Being one or two logs over is fine, but if it proves to be 6+ then I can't do that in good conscience, as I really like trees and would rather have them standing any day as compared to being horizontal and not needed.

[Gilman]

Sigidi,
The trick to not over cutting is to have a list of about 10 projects you want to build.  That way, you'll always need a little bit more lumber. ;)

[Ron Wenrich]

For the most part, International is what you will cut out of a log in 1" lumber.  Now, if your cutting patterns are for 2" then you will get more lumber than what the calculator will tell you.  How heavy you slab and the type of equipment you are using will also make a difference.

You could try the pulpwood metric methods, and see how close you come to it. 

Do you have the specifics of what you will be cutting?  If so, can you convert that to the English measure and figure up the board footage?  Then you will be looking at bd ft for both measures.  You should still be able to overrun tree scale with lumber scale. 

[sigidi]

THe particular job I am thinking so hard on, is a fella wants a 6x4m shed or 20x13' roughly and he wants to use trees from his block, I just don't want to tell him to put down say 7 trees for his framing and roof members, to then see him have more than one maybe two docked section of log left over, the other thing I don't want, is to need to bring the tree loper back in cause we have run short :

Maybe I can say to him it's only an estimate at best and if we err on the side of caution I will use or pay him for the extra logs not used? Then he wont have logs laying around for nothing - or even now I'm thinking on it, he may also have other projects in the pipeline which he could use his own timber on. THen I would cut the shed first and any left overs we can cut to a second wish list. THat might work a bit better

[beenthere]

Is it also possible that all the logs you saw up will not make the quality for framing and roof members, and you may need extra logs to make up that difference? Or are you pretty sure of the quality in the trees you will be cutting? 

Good luck with the project. With all your calculating, you will be in good shape. But use the Int'l scale to get the best estimate of what you should saw. You can fudge from that estimate, up or down.

[sigidi]

DOH!!!

I just realised, thanks BeenThere - you saved me some huge heartache. Of course all of the logs will not make structural grade, and I have been looking at volume of log like I would have no problems inside the trees which could mean thowing out a percentage.

Well over cutting on the volume it something I have to do - it's as simple as that

[Minnesota_boy]

Cutting a bit too much has never been a problem in this area, there are always a few other people who want to build something that will take the excess off your hands if you are willing to let them know you have them.