Trees for profit

Larry Caldwell larryc at teleport.com
Fri Apr 18 08:49:09 EST 1997


In article <01bc498a$37464d80$3a544dcf at woodtick.lebmofo.com>,
"Ron Wenrich" <woodtick at lebmofo.com> wrote:

> Not to quibble over oak vs Doug fir, but oak is has higher bending
> strength, better compression strength, higher in hardness, more shock
> resistant, and harder to split than Douglas fir.  However, Douglas fir is
> stiffer.  DF is not cheaper on the East Coast.  Structural timbers are
> sometimes made of hemlock or white pine.  Railroads use oak.

I'm sorry you don't like to quibble.  I love it. :)  Sometimes I start
quibbling as soon as I wake up.  I've even been known to quibble in my
sleep.

By strength I was referring to extreme fiber in bending strength.  Oak is
stiffer (higher modulus of elasticity) so isn't so springy.  Oak has a
higher compression strength perpendicular to the grain, I don't know about
parallel to the grain.  For temp shoring around here we commonly load doug
fir 2x4 studwalls  16" oc at 3000 lbs/lineal foot.  A stud wall is the
most overdesigned structure in the world in compression.

For shock resistance I would think it depends on the shock.  Doug fir
will support huge short duration loads, but as you note, it splits easily.
The wood also fatigues, so static loading is only about 1/3 the allowed
live load.  I've seen old grain warehouse beams that were exhibiting 
compression and shear failure.  These were 4'x 6' beams spanning 10
feet.  The bending strength was adequate but the weight of the grain
had driven the supporting members into the wood about 5".

You should be seeing more doug fir in New England before too many more years.
It's a very popular species for plantations in northern Europe also.

> Veneer in red oak is 14"x8' minimum and has about 50 bf.  Veneer buyers use
> the Doyle scale.  Price is about $1500/Mbf.  A tree this size should be
> left stand, in my opinion.  If allowed to get to a 20" log, the volume is
> 128 bf.  A 24" log has 200 bf.  The time it takes to increase the diameter
> is less than it takes to grow to that size.

That's a good price for finish grade veneer around here too.  As I pointed
out, the really good logs never get peeled.  An 8' log around here is the
absolute minimum size that has any market value.  Anything shorter is a
cull out.  Of course, there is a market for burls, but that's a specialty
wood.  Minimum diameter for a doug fir #3 peeler is 24".

They peel some of the darndest things.  Cottonwood is a popular (pun)
surface wood.  The interior plies get pretty creative, with some odd
woods getting laminated in there.  Anything they can peel a firm veneer
out of gets used.

-- Larry




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