What going on with this wood?

[WDH]

I guess "dead" is a relative term when it comes to heartwood........

[Riles]

Reaction to stimuli would be insufficient evidence of life. Molten metal reacts to water used to quench it, but you shouldn't claim it's alive.

I think you have to make the distinction between reactions that occur IN a place and reactions that occur BY the place. If the heartwood is compartmentalizing because the extractives can't make it past the wound that's one thing. If the heartwood cells are producing the extractives to seal the wound, that's another.

Did you know you can't kill a virus? They're not alive, you have to deactivate them (according to my old botany professor). 

[Mike_Barcaskey]

heartwood cells react to the stimuli of injury or pathogen in an ordered fashion

instead of your metal let me use a light bulb. a hot light bulb reacts when water is thrown on it, it breaks. a result of the material shrinking/expanding and breaking
the analogy to heartwood would be that the light bulb would react by changing it's cellular structure to avoid breaking when hit with the water.

heartwood cells could react to the stimuli of injury or pathogen in any number of ways, but they react in such a way as to compartmentilize/fight off the problem. something is clicking at the cellular for the exact thing needed to happen

[Riles]

The heartwood might be changing it's structure, but the changes are being done TO the heartwood, not BY the heartwood.

Along the same lines of your argument, there's a concept that the earth is alive because there are analogues for lungs (the earth "breathes"), circulatory system, can repair itself, etc. (Gaia theory).

[Dodgy Loner]

Well, some heartwood must be dead, else we wouldn't have hollow trees .

[beenthere]

Yep, I'd say dead and gone....dust to dust   

[Mike_Barcaskey]

I believe Shigo's observations were that the changes were BY the heartwood

[metalspinner]

I believe we sawed a white oak with that last year.  I was a reallty cool effect.  However, my white ring appeared to be marked like a snake skin.  I hope to unstack it to load in the kiln at the end of the fall.  Will take pics then.

[SwampDonkey]

Compartmentalization is done by the sapwood I believe. How does your tractor blade get to the heartwood without passing through the sapwood? I would agree there is a transition zone between heart and sap and some cells in the heartwood perimeter continue to live for a time, but soon expire. I doubt anyone could put an exact time frame on this. But, the deeper the heartwood the less oxygen, no oxygen no cellular respiration, thus dead.

Here's one line of thinking from the Wood Tech Book to determine heartwood.

When the cell becomes inefficient in using food produced by photosynthesis, and stored in the parenchyma cells, it in turned into extractives and this reaction is irreversible. The less efficient a particular species is in using the photosynthates, the more heartwood is formed. As you go deeper into the heart of the tree from the sapwood the shape of the nuclei of the storage cells changes from roundish to rectangular and as you go deeper still the nuclei are non existent. The loss of stored food as you go from sap to heart causes a change in the enzymes of the cells and residual oxygen will oxidize, which polymerizes phenolic materials present in the parenchyma cells, leading to formation of pigments giving the color of heartwood. Extractives are lethal to pathogens. Lack of oxygen and reduced permeability in the heartwood is inhospitable to fungal attack as well.


And for Dodgy  And slap myself on the forehead for not remembering the term.

Streaks of light-colored wood that have the appearance and properties of normal sapwood are found embedded in the heartwood; such tissue is described as included sapwood. This is a misnomer, however, since such light-colored areas contain no living cells. Included sapwood may occur in any tree species; it is especially common in western red cedar and eastern red cedar. The exact cause has not been fully determined.

Further, lighter zones or streaks are often present in heartwood, simulating included sapwood; they form as a result of incipient decay. Portions of the heartwood become bleached as a result of the fungous action.

[source:Textbook of Wood Technology]

[MikeH]

 I go with "Moon Ring" then, thank you all for your help.

[Don P]

I googled on traumatic heartwood and came up with a little more reading material, kinda related, from Dr Shigo's articles.
http://www.treedictionary.com/DICT2003/shigo/AUTO.html

I've viewed heartwood cells as dead and sapwood cells as living. The average lifespan of a wood cell is the number of rings of sapwood 
In equating a tree to an animal, a tree has nowhere to poop. It packs the spent sugars and chemicals from its life processes in towards the heart of the tree until those cells die from the "pollution". If a band of wood loses its capillary ability I could see it not having those spent byproducts packed into it. Redcedar's blocky included sap has made me ponder several times, don't know if that's right, all straight outta my imagination  .

[SwampDonkey]

Don, seems I read that in the Wood Tech book. What you wrote just elaborates a bit more. I condensed my reply. But, it varies by species. Take butternut, very little sapwood in it. Maybe an inch?

Note that the 'false heartwood' mentioned in the article was sapwood compartmentalizing the dead branch. Not the same as 'moon ring' or included sapwood. It was in that zone of living tissue. Some trees have it deeper, some shallower, again depends on species.

[jim king]

This may help or make more confusion but this is from our scientist who does our ID work.

Jim,wood id mihaly.htm

    The development of color in heartwood is just the tip of the
iceberg, as it were, of the chemical changes that take place during
transition from sapwood to heartwood, but it is something that we can
easily notice and appreciate.  The role of these chemical changes is to
make the wood tissue chemically protected and physically sealed for
durability and resistance to insects and fungi.
    There are 200-300 secondary metabolites, chemicals other than DNA,
sugar, proteins and players of essential metabolism, in any plant
tissue, including wood. Heartwood is special in that there is no DNA,
sugar, proteins or nitrogen left in it since it is dead tissue. These
chemicals were produced as the last act of plant metabolism in these
tissues. They are the products of dozens of biochemical programs,
encoded in DNA, and they run simultaneously, sometimes competing, their
relative speed depending on environmental (including minerals, stress,
and pathogens) and internal factors (genetic program in DNA). The end
result is, depending on the species, is a more or less uniform or very
variegated heartwood color. But there are always at least some of all
the chemicals present. It is their relative proportion and distribution
that changes, giving rise to visible patterns of color, patterns of
fragrance and invisible patterns of chemical deposition.
    Stress from drought, mineral deficiency, abundance, and most
importantly the constant attack by borers and fungus causes multitudes
of chemical responses in the wood and mostly this is what causes the
patterns. The color pattern is a visual snapshot of combat situations
and moving fighting fronts frozen for eternity at the time of heartwood
formation. Plants have a lot of chemical defenses that act like
immunity. Colored substances often tend to react with DNA, hence the
color in wood.
    Minerals may contribute but not as much as the layman's notion.
Plants regulate what they take up by their roots and only few chemicals
can be taken up in excess.

 

When the defenses of wood are broken, spalting happens. Spalting also
produces colors which are a combined result of the sapwood and the
microbe, therefore more colors may be produced then what the tree alone
could produce, and this may be specific to a given location or unique.
Many fungus are colored themselves, most have melanin that appears
bluish or black, brown.

 

I use chemical fingerprinting to distinguish and classify samples but I
still use a microtome to make thin sections for microscopy when I
already have a guess. As I said, the information on wood anatomy and
plant diversity of the region is insufficient and spread between
hundreds of articles and books, so keying out a species is not
instantaneous to say the least. But I am better prepared for legumes
and
especially Dalbergia and Machaerium because I already have done the
literature research.

 

We should be mindful of the sensitivities of the local botanists and
should observe the local regulations. On the long term this study would
ideally benefit the local or national university in the form of
herbarium material and shared data, and should not appear as
exploitation. Just how to go about it should be sensibly worked out.

 

Pink woods: Truly clear pink woods are rare and therefore valuable.

Pink ivory is a deep pink wood, often without figure.

But even in Peru there should be some tulipwood (Dalbergia
decipularis),
which is streaked with pink. Then you have bloodwood (Brosimum) which
could be deep red or purplish pink, like your rainbow wood. I also
expect Simira, which is brick red in the heartwood, but neon pink in
the
sapwood or wherever you break the epidermis. Then Aspidosperma, which
in
Colombia produces neon pink with some yellow splashes.

 

I cannot immediately recall more. Most other woods are not pure pink.
Pure purple colors are also not common. Peltogyne is outstanding of
course. But queenwood is remarkable with its magenta colors even though
it mutes into brown.


More later.