I bought a book 'Turning Green Wood' by Michael O'Donnell. In it he explains
reaction wood in branches, he says:

"Hardwood in the northern hemisphere build the reation wood on the tension
side of the pith, which gives rise to growth rings in branches being wider
on the tension side (the upper side) than on the compression side. In the
southern hemisphere this is reversed."

This poses some interesting questions:

1. How does a tree know whether it is in the northern or southern
hemisphere?
2. Do tree branches on the equator have equal size growth rings above and
below the pith?
3. If I send an acorn from England to Australia will the resulting oak have
reaction wood as its parents or as its environment?

Something to muse on?

BillR

Bill,
I got the same book, and that part left me scratching my head. Last
fall I got a Walnut branch that came off horizontally. It was about 24
inches high, and 12 inches wide. The pith was located about 6 inches
down from the top of the branch. This seems to hold true for every
other leaning tree and branch that I have collected. The extra build up
is on the compression side of the tree and not on the tension side.
robo hippy



















Bill R wrote:
I bought a book 'Turning Green Wood' by Michael O'Donnell. In it he
explains
reaction wood in branches, he says:

"Hardwood in the northern hemisphere build the reation wood on the
tension
side of the pith, which gives rise to growth rings in branches being
wider
on the tension side (the upper side) than on the compression side. In
the
southern hemisphere this is reversed."

This poses some interesting questions:

1. How does a tree know whether it is in the northern or southern
hemisphere?
2. Do tree branches on the equator have equal size growth rings above
and
below the pith?
3. If I send an acorn from England to Australia will the resulting
oak have
reaction wood as its parents or as its environment?

Something to muse on?

BillR

Bill R wrote:
I bought a book 'Turning Green Wood' by Michael O'Donnell. In it he explains
reaction wood in branches, he says:

"Hardwood in the northern hemisphere build the reation wood on the tension
side of the pith, which gives rise to growth rings in branches being wider
on the tension side (the upper side) than on the compression side. In the
southern hemisphere this is reversed."

It's not April 1st already is it?

--
Alun Saunders

Just a test--keep moving on, nothing happening here.


"robo hippy" wrote in message
ups.com...
Bill,
I got the same book, and that part left me scratching my head. Last
fall I got a Walnut branch that came off horizontally. It was about 24
inches high, and 12 inches wide. The pith was located about 6 inches
down from the top of the branch. This seems to hold true for every
other leaning tree and branch that I have collected. The extra build up
is on the compression side of the tree and not on the tension side.
robo hippy



















Bill R wrote:
I bought a book 'Turning Green Wood' by Michael O'Donnell. In it he
explains
reaction wood in branches, he says:

"Hardwood in the northern hemisphere build the reation wood on the
tension
side of the pith, which gives rise to growth rings in branches being
wider
on the tension side (the upper side) than on the compression side. In
the
southern hemisphere this is reversed."

This poses some interesting questions:

1. How does a tree know whether it is in the northern or southern
hemisphere?
2. Do tree branches on the equator have equal size growth rings above
and
below the pith?
3. If I send an acorn from England to Australia will the resulting
oak have
reaction wood as its parents or as its environment?

Something to muse on?

BillR

Bill R wrote:
"Hardwood in the northern hemisphere build the reation wood on the tension
side of the pith, which gives rise to growth rings in branches being wider
on the tension side (the upper side) than on the compression side. In the
southern hemisphere this is reversed."

Maybe he was thinking of growth rings. I hear they go round the tree in
the opposite direction down under



--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
http://chipshop.blogspot.com
http://groups.yahoo.com/group/toolrest/

"Bill R" wrote: (clip) 2. Do tree branches on the equator have equal size
growth rings above and below the pith?(clip)
^^^^^^^^^^^^^
Only for those branches which lie directly above the equator (pointing east
or west.) As the angle of the branches shifts toward north or south, the
position of the pith moves up or down. Because of statistical uncertainty,
and lack of sufficient data, it is not clear whether the shift is
proportional to the angle, or to the sine of the angle.

Another interesting effect is that trees that grow at the north or south
poles do not grow at all.

Did you know that water leaving the bathtub drain swirls counter-clockwise
below the equator?

Barry


"Bill R" wrote in message
...
I bought a book 'Turning Green Wood' by Michael O'Donnell. In it he
explains
reaction wood in branches, he says:

"Hardwood in the northern hemisphere build the reation wood on the tension
side of the pith, which gives rise to growth rings in branches being wider
on the tension side (the upper side) than on the compression side. In the
southern hemisphere this is reversed."

This poses some interesting questions:

1. How does a tree know whether it is in the northern or southern
hemisphere?
2. Do tree branches on the equator have equal size growth rings above and
below the pith?
3. If I send an acorn from England to Australia will the resulting oak
have
reaction wood as its parents or as its environment?

Something to muse on?

BillR

Apparently not.

Bill R wrote:
I bought a book 'Turning Green Wood' by Michael O'Donnell. In it he explains
reaction wood in branches, he says:

"Hardwood in the northern hemisphere build the reation wood on the tension
side of the pith, which gives rise to growth rings in branches being wider
on the tension side (the upper side) than on the compression side. In the
southern hemisphere this is reversed."

I vaguely recall that Hoadley says something similar but it was
concerning hardwood v softwood rather than hemispheres. Too late to
look it up at the moment. That ring a bell w/anyone?

....Kevin
--
Kevin Miller
http://www.alaska.net/~atftb
Juneau, Alaska

"Bill R" wrote in message
...
I bought a book 'Turning Green Wood' by Michael O'Donnell. In it he
explains
reaction wood in branches, he says:

"Hardwood in the northern hemisphere build the reation wood on the tension
side of the pith, which gives rise to growth rings in branches being wider
on the tension side (the upper side) than on the compression side. In the
southern hemisphere this is reversed."

This poses some interesting questions:

1. How does a tree know whether it is in the northern or southern
hemisphere?
2. Do tree branches on the equator have equal size growth rings above and
below the pith?
3. If I send an acorn from England to Australia will the resulting oak
have
reaction wood as its parents or as its environment?

Something to muse on?

BillR

Two words: Coriolis force.

todd

I vaguely recall that Hoadley says something similar but it was
concerning hardwood v softwood rather than hemispheres. Too late to
look it up at the moment. That ring a bell w/anyone?

From Textbook of Wood Technology, Panshin and De Zeeuw, Vol 1 1949, 2nd
ed 1964.

Reaction wood is produced on the wide side of eccentric cross sections.
The reaction wood of gymnosperms is called compression wood because it
forms on the lower or compression side of leaning stems. The reaction
wood in hardwoods ...... the name tension wood arises from the fact that
the increased growth takes place on the upper or tension stress side of
leaning trees.

It then goes into considerable detail about the cellular, chemical and
physical properties of both types of reaction wood. Most notably the
longitudinal shrinkage when drying increases, typically by 100% but upto
300% in white oak.

--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
http://chipshop.blogspot.com
http://groups.yahoo.com/group/toolrest/

I have done some Google searches and can find no evidence that there is
a difference between hemispheres. In fact a couple of papers from Chile
and South Africa would seem to suggest that their hardwoods work the
same as in the north.

I did however find one reference that says that the coriolis effect does
change the direction of spiral grain

Does anyone have access to the books that Mike O'Donnell lists in his
bibliography?

--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
http://chipshop.blogspot.com
http://groups.yahoo.com/group/toolrest/

"Bill R" skrev i melding
...
I bought a book 'Turning Green Wood' by Michael O'Donnell. In it he
explains
reaction wood in branches, he says:

"Hardwood in the northern hemisphere build the reation wood on the tension
side of the pith, which gives rise to growth rings in branches being wider
on the tension side (the upper side) than on the compression side. In the
southern hemisphere this is reversed."


They also have their panhandles on the other side of
their pans, due to their being on the opposite side of the earth.

Bjarte

Is that where my left handed frying pan came from?

--
God bless and safe turning
Darrell Feltmate
Truro, NS Canada
www.aroundthewoods.com

Why not ask O'Donnell? I tried, but I couldn't find a net address.
Anyone?

Musing about Bill's question; a long time ago England sent lots of
people and acorns to Australia and America both have reacted very well.


Turn to Safety, Arch
Fortiter



http://community.webtv.net/almcc/MacsMusings

"Millers" wrote in message
...
Bill R wrote:
I bought a book 'Turning Green Wood' by Michael O'Donnell. In it he
explains
reaction wood in branches, he says:

"Hardwood in the northern hemisphere build the reation wood on the
tension
side of the pith, which gives rise to growth rings in branches being
wider
on the tension side (the upper side) than on the compression side. In
the
southern hemisphere this is reversed."

I vaguely recall that Hoadley says something similar but it was
concerning hardwood v softwood rather than hemispheres. Too late to
look it up at the moment. That ring a bell w/anyone?

...Kevin
--
Kevin Miller
http://www.alaska.net/~atftb
Juneau, Alaska

The chapter in the book also goes on to say that the size of the growth
rings of softwood are opposite to that of hardwood and also reverse in the
southern hemispere.

This may mean that in the southern hemispere the meaning of soft and hard
may be reversed.

No - this is starting to make my head hurt.

BillR

Well, I went out to collect another black walnut tree yesterday, and
checked and confirmed, the buildup on limbs is on the compression side
of the branch and tree, not the tension side.
robo hippy

So you live in the northen hemisphere. All we need now is an Aussie or Kiwi
to stop sunning themselves (lucky dogs) and go and lop a branch and report
back.

BillR

"robo hippy" wrote in message
ups.com...
Well, I went out to collect another black walnut tree yesterday, and
checked and confirmed, the buildup on limbs is on the compression side
of the branch and tree, not the tension side.
robo hippy

"Bill R" wrote in message
All we need now is an Aussie or Kiwi
to stop sunning themselves (lucky dogs)

Most of us around northern Australia try and avoid the sun if at all
possible. Its just too bloody hot in summer. Thoug I imagine, as much as we
complain about the heat, we would complain even louder if we had below zero
maximums.
Mick

Mike,

From what you say about the temperature I suspect you do not have a wood
pile like our American and Canadian cousins, unless you have a wood burning
freezer.

I would like to know whether the reversal of reaction wood north/south is
true or just one of those myths that just gets repeated until people believe
it.

BillR

"Michael Lehmann" wrote in message
...

"Bill R" wrote in message
All we need now is an Aussie or Kiwi
to stop sunning themselves (lucky dogs)

Most of us around northern Australia try and avoid the sun if at all
possible. Its just too bloody hot in summer. Thoug I imagine, as much as
we
complain about the heat, we would complain even louder if we had below
zero
maximums.
Mick

Bill R wrote:
So you live in the northen hemisphere. All we need now is an Aussie or Kiwi
to stop sunning themselves (lucky dogs) and go and lop a branch and report
back.


It's been a long winter. I propose we all go to NZ or Oz and check for
ourselves. I could use the break...

....Kevin
--
Kevin Miller
http://www.alaska.net/~atftb
Juneau, Alaska

Bill, send me your email address by removing the asterisk and I'll send you
a pic of the next tree I cut down. (If your interested)
Its not a real big tree though, maybe 300 dia. (12")
mick
"Bill R" wrote in message
...
Mike,

From what you say about the temperature I suspect you do not have a wood
pile like our American and Canadian cousins, unless you have a wood
burning
freezer.

I would like to know whether the reversal of reaction wood north/south is
true or just one of those myths that just gets repeated until people
believe
it.

BillR

"Michael Lehmann" wrote in message
...

"Bill R" wrote in message
All we need now is an Aussie or Kiwi
to stop sunning themselves (lucky dogs)

Most of us around northern Australia try and avoid the sun if at all
possible. Its just too bloody hot in summer. Thoug I imagine, as much as
we
complain about the heat, we would complain even louder if we had below
zero
maximums.
Mick

Its been a long summer, cant wait for it to finish
mick


"Millers" wrote in message
...

It's been a long winter. I propose we all go to NZ or Oz and check for
ourselves. I could use the break...