Timber inventory help

[BigJim2185]

I'm getting close to purchasing a bandsaw mill to produce timbers and boards for a timber frame home build.  I am planning to harvest trees from my property.  Before making any purchases, I want to be sure that the pines I can access easily with my current equipment will be usable for the timbers I am hoping to mill from them. 

Can I count a tall straight growing 12" - 14" dbh tree as as good for an 8" x 8" x 14'?

Can you guys give me a few things to look for as I select trees for harvest?  For example, when looking at branches/knots, where do I draw the line between a log that will produce a good timber vs. a knot what will affect strength? 

I will likely end up asking if the guy who is designing my frame (an experienced sawyer and timber framer) will walk the stands and consult, but in the meantime, any wisdom you guys can share would be much appreciated!

[Magicman]

Can I count a tall straight growing 12" - 14" dbh tree as as good for an 8" x 8" x 14'?

Depending on how straight "straight" is, and how much taper the tree has.  It also depends upon whether any/how much wane is acceptable.  The small end of the 14' log will determine what it will cut, not the butt diameter nor the dbh.

[WoodenHead]

To make an 8" x 8" I generally like to see a log at least 12" in diameter at the small end (and inside the bark).  At 11" you would want a perfect cylinder and you will still have to accept some wane.   

[Ron Wenrich]

We have a tool box that will tell you the minimum size log you need to make a cant.  Left hand side, at the bottom.  If you want an 8x8 cant, then you'll need a log that is a minimum of 11.3".  I would want a little more wiggle room. 

A white pine of that size would probably have a form class of about 80.  That means a 14" dbh tree will be about 80% of that at 17', inside bark.  That would be at the end of the first 16' log.  That comes out to 11.2", so that's cutting it close.  A 12' log probably wouldn't be too much of a problem.  A 12" dbh pine would probably make it at 8'. 

As for knots, a lot depends on how well the trees have pruned themselves over the years.  If the branches are hanging on the tree, you might have some issues with black knots.