| Our past research on microbial
and enzymatic degradation of wood and wood components has provided
a great deal of information that has been useful in helping to protect
and conserve historic and archaeological wood. In addition to our
investigations on biological and non-biological degradation processes
in the expedition huts of Antarctica (link
to Antarctic research), studies have been done or are currently
underway with The Getty Conservation Institute, The Metropolitan
Museum of Art, The American Museum of Natural History, the U. S.
National Park Service, The Institute for Nautical Archaeology, as
well as many archaeologists and conservators working to preserve
wooden cultural properties around the world.
A few projects are listed here to demonstrate how
our research is being used to better understand deterioration processes
that affect ancient woods and to help preserve these national and
international heritage sites long into the future. Our research
is also providing important new information on the biology and ecology
of these little known microorganisms that attack wood
and other organic materials.
An ancient Egyptian wooden statue (2340 B. C.)
from a tomb in Saqqara now in the Metropolitan Museum of Art,
New York. Photo courtesy of the Metropolitan Museum of Art.
Coffin from Abydos (2400-2200 BCE) |
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Transmission electron micrograph of a section
from the Scribe of Mitre Statue showing severely degraded cell
walls caused by a brown rot fungus. The attack occurred in the
tomb before excavation. The wood is extremely weak and easily
fractures into dust-like particles. Our research provides information
on the types of decay found in ancient tombs and is used by
conservators to determine the most appropriate methods of preserving
the ancient cultural properties.
For more information on deterioration
in ancient Egyptian woods see pdf file of: Blanchette et al.
Assessment of deterioration in archaeological wood from ancient
Egypt. Journal
of the American Institute of Conservation 33:55-70.
Scanning electron micrograph of wood decay in an Old Kingdom wooden object from Abydos showing soft rot is the major decay at this desert burial site. For more information about this project see our recent publications on:
Wood decay in ancient Egyptian wood and
Conservation of these ancient wooden objects. |
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Waterlogged Woods
From Ancient Shipwrecks
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Underwater excavation of the Uluburun, a 14th
century B. C. Late Bronze Age shipwreck, by Cemal Pulak, Photo
courtesy of the Institute of Nautical Archaeology. In addition
to wood from the ship, ebony logs that were part of the ships
cargo were also found.
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Scanning electron micrographs of sections
from the ship hull showing extensive bacterial degradation
of the wood cells. Bacterial attack of waterlogged wood causes
loss of wood strength. The wood cells shown in the bottom
photo are distorted and have collapsed due to the lack of
cell wall integrity.
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Deterioration in Thomas Edison's Historic
Laboratory
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A view of Thomas Edison's historic laboratory in Fort Myers,
Florida.
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An unusual type of wood deterioration was found to be taking
place in the laboratory. This damage was caused by a caustic
chemical spill that occurred long ago and resulted in a slow
defibration of the wood. Over many years, very serious damage
has resulted.
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The chemical corrosion of the wood over many decades resulted
in wood cells detaching and separating into a fibrous mass.
This scanning electron micrograph demonstrates the degradation
took place in the middle lamella between the cells leaving
only the secondary wall layers of the wood cells .
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Tumulus MM - The Ancient Tomb of
King Midas
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This large mound in Turkey called Tumulus
MM, thought to be the tomb of King Midas, contains the
largest wooden tomb ever found. No gold was found in the
tomb but spectacular furniture, a massive coffin with
the King and many other items were discovered in the tomb
that dates to 700 B.C. |
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Our investigations have shown that a soft
rot type of wood destroying fungus was responsible for the
decay in the tomb and this ancient fungus was likely causing
decay for hundreds, possibly thousands of years.
For additional information on:
The fungi in the tomb see:
Filley, T. R., R. A. Blanchette, E. Simpson and M. L. Fogel.
2001. Nitrogen cycling by wood decomposing soft-rot fungi
in the “King Midas tomb”, Gordion, Turkey. Proceedings
of the National Academy of Science 98: 13346-13350.
Information on how this research has help
conservators find the best treatments to preserve the wood
see:
Spriydowicz, K., E. Simpson, R. A. Blanchette, A. Schniewind,
M. Toutloff and M. Murray. 2001. Preserving dry archaeological
wood with polyvinyl acetal resins: a case study. Journal of
the American Institute of Conservation 40:43-57.
Information on decay and pseudomorphs produced
in the tomb see:
Blanchette, R.A. and E. Simpson. 1992. Soft rot decay and
wood pseudomorphs in an ancient coffin (700 BC) from tumulus
MM at Gordion Turkey. International Association of Wood Anatomists
Bulletin. 13:201-213. |
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When the tomb was opened the bones of the
King were found on a massive cedar coffin within the wooden
tomb structure. Huge cut pine timbers formed the walls of
the tomb with cedar timbers used for the floor. This inner
wooden tomb structure was also covered by large juniper logs.
Decay was evident in the structure and wooden contents of
the tomb. Photo is courtesy of the University Museum, University
of Pennsylvania.
Scanning electron micrograph of a section
from the decayed wood showing a soft rot attack. This fungus
caused cavities to form within the cells walls of the wood.
Our investigations have also shown that the fungus was able
to tolerate very adverse conditions and obtained nitrogen
needed to decay the wood from the King's body. Carbon and
nitrogen isotope analyses show the King's nitrogen was translocated
by the fungus into the floor, walls and even the ceiling of
the tomb as it attacked the wood. Throughout the tomb only
one type of decay was found.
This work was done in cooperation with Professor
Timothy Filley from Purdue University; Professor Elizabeth
Simpson, Director of the Gordion Furniture Project, Bard Graduate
Center for Studies in the Decorative Arts, New York; Professor
G. Kenneth Sams, University of North Carolina; The Department
of Antiquities, Ministry of Culture of the Turkish Republic
and the Museum of Anatolian Civilization, Ankara, Turkey. |
Prehistoric Great Houses of the Southwestern
United States
![]() Research
is underway at Chaco Culture National Historic Park and Aztec
Ruins National Monument in New Mexico to assess the types and
extent of deterioration currently occurring in the wood of the
great houses, determine the wood species used in their construction
and evaluate reburial methods currently being used to preserve
some of the great houses that are rapidly deteriorating. Although
the Chacoan great houses were made of mud brick, they also contained
large quantities of wood in their construction. Tens of 1000s
of trees were used for beams, secondary roof supports and door
and window lintels. Today, these great houses have one of the
largest samples of prehistoric wood left of any site in the
American Southwest. In the West Ruin of Aztec Ruins National
Monument alone, over 6000 pieces of wood still exist. The wood
is an integral part of the surviving Chacoan architecture and
has served as a valuable resource for determining the exact
age of the structures and for obtaining information about raw
material production, procurement and harvesting methods.
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View of Pueblo Bonito at Chaco Canyon, New
Mexico |
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Chetro Ketl, a great house at Chaco Canyon, showing large
wooden beams in the ruins.
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Wood from one of the lintels that has been decayed. Both brown
rot and soft rot fungi have been found in the great houses.
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Salt deterioration also is causing problems on some woods.
This beam has been deteriorated by salts that have precipitated
on the exposed wood over many years.
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The same area of Chetro Ketl shown in the
above photo that has been reburied to preserve the mud brick
and wood in the great house.
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![]() The
reburial of archaeological sites as an effective conservation
strategy to protect masonry structures and wood is currently
being used to insure preservation of the Chacoan prehistoric
structures for the future. For these programs to be successful,
the agents responsible for deterioration and the reburial
environment are being studied so that conservation plans will
effectively prevent future biological and non-biological deterioration
from taking place. These investigations, in cooperation with
the Getty Conservation Institute and the National Park Service,
will monitor the reburied sites over time to insure the environment
is not conducive to decay and the buried wood is being protected
from degradation.
For additional information on conservation
of the prehistoric great houses, wood used in the structures
and deterioration taking place see:
Blanchette, R. A., B. W. Held, J. A. Jurgens.
2004. Wood Deterioration in Chacoan Great Houses of the Southwestern
United States. Conservation and
Management of Archaeological Sites 6:204-212.
Ford, D., M. Demas, N. Agnew, R. Blanchette,
S. Maekawa, M. Taylor and K. Dowdy. 2004. Chaco Canyon reburial
programme. Conservation and Management of Archaeological Sites
6:177-202.
Follow
this link for results from studies on wood identification
in the Chacoan great houses |
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