Andi Wolfe wrote:

"In the northern hemisphere this is formed in the upper side of the
limb in hardwoods and the lower side in soft woods. The reverse is
true for trees in the southern hemisphere."


Ken - I saw this statement in the book, also, and don't know quite
what to make of it.

Reaction wood is a descriptor for the larger spacing of growth rings
on one side of the pith relative to the other on branches. There is a
difference in how the wood reacts as it's drying, which explains the
name.

I'll have to dig into the literature to see if there is a difference
among plant families in how the branches put on secondary growth. If
the above statement is anecdotal in nature, it may just be referring
to differences among plants that typically occur in one hemisphere vs
the other.

Andi
http://www.AndiWolfe.com

I've heard it called "tension wood" and "compression wood" which is
a better descriptor than "reaction wood". If you think of growth rings
as rubber bands the following makes sense.

For a tree that is leaning off of vertical - the "uphill" side of each
growth ring is in tension, stretched as it tries to bring the tree
vertical, or at least prevent it from falling over farther. The growth
ring on the "downhill" side of the tree isn't be stretched at all - but
rather it's being compressed. Each behaves differently when cut,
as in sawing a cross section into two halves.

Here's an illustrated and annoted explanation that may help

http://web.hypersurf.com/~charlie2/T...insawing3.html

Charlie,

One thing that you may want to add to your wonderfully illustrated
explanation: the branch cut parallel to the ground will yield bowls with
more symmetric grain, which IMHO is much more desirable than a little bit
bigger blank.

Regards,

Steve
"charlieb" wrote in message
...
Andi Wolfe wrote:

"In the northern hemisphere this is formed in the upper side of the
limb in hardwoods and the lower side in soft woods. The reverse is
true for trees in the southern hemisphere."


Ken - I saw this statement in the book, also, and don't know quite
what to make of it.

Reaction wood is a descriptor for the larger spacing of growth rings
on one side of the pith relative to the other on branches. There is a
difference in how the wood reacts as it's drying, which explains the
name.

I'll have to dig into the literature to see if there is a difference
among plant families in how the branches put on secondary growth. If
the above statement is anecdotal in nature, it may just be referring
to differences among plants that typically occur in one hemisphere vs
the other.

Andi
http://www.AndiWolfe.com

I've heard it called "tension wood" and "compression wood" which is
a better descriptor than "reaction wood". If you think of growth rings
as rubber bands the following makes sense.

For a tree that is leaning off of vertical - the "uphill" side of each
growth ring is in tension, stretched as it tries to bring the tree
vertical, or at least prevent it from falling over farther. The growth
ring on the "downhill" side of the tree isn't be stretched at all - but
rather it's being compressed. Each behaves differently when cut,
as in sawing a cross section into two halves.

Here's an illustrated and annoted explanation that may help

http://web.hypersurf.com/~charlie2/T...insawing3.html

C & S wrote:

Charlie,

One thing that you may want to add to your wonderfully illustrated
explanation: the branch cut parallel to the ground will yield bowls with
more symmetric grain, which IMHO is much more desirable than a little bit
bigger blank.

Regards,

Steve


Steve:

It's not clear to me what you mean by
"the branch cut parallel to the ground will yield bowls with
more symmetric grain"

Look at Illustration A & B on the following page I earlier
pointed to.

http://web.hypersurf.com/~charlie2/T...insawing3.html

In both cases, the log is cut into two "halves" - along the
Pith Line, "A" leaving the same amount of tension and
compression wood in each "half" while "B" leaves all of
the tension wood in one "half" and all the compression
wood in the other.


One interpretation of the "parallel" part of your statement
would be as shown on this temporary page I just put up for
purposes of discussion.

http://web.hypersurf.com/~charlie2/TemporaryStuff.html

Rather than cutting along the pith line, this method would
cut THROUGH the pith line at an angle - determined by
a line parallel to the ground when the branch section was on
the tree.

Is that what you had in mind? If not, could you clarify a bit
and I'll try and illustrate it.

charlie b

B-cut will yeild symmetric grain (blanks c and d).
A- will have the center of the grain *not* running through the center of the
bowl (blanks a and b).

regards,

Steve



"charlieb" wrote in message
...
C & S wrote:

Charlie,

One thing that you may want to add to your wonderfully illustrated
explanation: the branch cut parallel to the ground will yield bowls with
more symmetric grain, which IMHO is much more desirable than a little
bit
bigger blank.

Regards,

Steve


Steve:

It's not clear to me what you mean by
"the branch cut parallel to the ground will yield bowls with
more symmetric grain"

Look at Illustration A & B on the following page I earlier
pointed to.

http://web.hypersurf.com/~charlie2/T...insawing3.html

In both cases, the log is cut into two "halves" - along the
Pith Line, "A" leaving the same amount of tension and
compression wood in each "half" while "B" leaves all of
the tension wood in one "half" and all the compression
wood in the other.


One interpretation of the "parallel" part of your statement
would be as shown on this temporary page I just put up for
purposes of discussion.

http://web.hypersurf.com/~charlie2/TemporaryStuff.html

Rather than cutting along the pith line, this method would
cut THROUGH the pith line at an angle - determined by
a line parallel to the ground when the branch section was on
the tree.

Is that what you had in mind? If not, could you clarify a bit
and I'll try and illustrate it.

charlie b