Archaeobotanists

When I use the term wet wood to refer to dry wood that has been
wet(rain, dampness ...), in other words wood that is dead when
collected, but has high moisture content from external conditions. Green
wood refers to wood that has been collected while living tissue is still
present and whose moisure content is from the normal physiological
processes internal to a woody plant.

Whether the water source makes a functional difference to combustion and
carbonization is uncertain. Water is water, but some of the volatiles,
etc., present in green wood surely are not be present in wet wood. Some
woods have a reputation to burning when green, others to burning when
wet, but off the top of my head I can't remember any that have a
reputation for burning when green or wet.

Dr Dufraisse raises a fascinating point, is fusing (glassiness) a result
of immediate post-carbonisation processes, as well as or instead of
taxa, chemistry etc. In my burning experiments I have never attempted to
suddenly cool the charcoal, always allowing a gradual cooling, and there
is certainly more fused charcoal in archaeological material than
experimental material I have looked at.

There is an enormous amount of science of carbonization not just of
cellulose but of other wood components and of whole wood, though far
less of large "firewood" sized material. Perhaps I should publish a
bibliography.

Can any anglophones out there publish a summary of Théry -Parisot's work
for us regrettably poor-francophones.

nic

"Dr. Alexa Dufraisse" wrote:
> 
> Hello everybody,
> I am a new member of the archaeobotany list. My name is Alexa Dufraisse, I am
> french (so excuse for my english) and my work is focussed on charcoal analysis
> in waterlogged sites, especially located in the circum-alpine area in Europe.
> At the moment, I am working in Basel (postdoc) at the lakes of Zürich and
> Constance.
> 
> I just have read your discussions about the glassy charcoal. There is another
> hypothesis about the vitrification of charcoal : a quick cold growing for
> example by water. Is there someone which had worked on this problem? I have
> also worked on salt spring exploitation in the french Jura. I did with the
> collaboration of archaeologists few experimentations. They showed that in order
> to crystallize salt, we have to water the hearth with salt water which creates
> a cold. But, among the experimental and archaeological charcoals, I did not
> observed more glassy charcoal....
> 
> I have another question : what is in English the difference between wet wood and
> green wood? Is it a problem of the percentage of the humidity or between living
> trees and "just cut trees" or other....?
> 
> Best regards
> Alexa Dufraisse
> --
> Alexa Dufraisse
> Universität Basel
> IPNA, Institut für Prähistorische und Naturwissenschaftliche Archäologie
> Spalenring 145
> CH-4055 Basel
> Tel +41 61 201 02 17
> 
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-- 
Nic Dolby

School of Geography & Environmental Science
Monash University
CLAYTON, VIC., 3800
Tel.: +61-3-9905-2919 (or Dept Office +61-3-9905-2910)
Fax: +61-3-9905-2948
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