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Norwegian wood for the ages
14 October 2009
The Norwegian University of Science and Technology (NTNU)
Norwegian scientists have found “mummified” pine trees, dead for nearly 500 years yet without decomposition.
Norway’s wet climate seems perfect for encouraging organic matter to rot – particularly in Sogndal, located on Norway’s southwestern coastline, in one of the most humid, mild areas of the country. In fact, with an average of 1541 millimetres of rain yearly and relatively mild winters, Sogndal should be an environment where decomposition happens fast. Not so.
“We were gathering samples of dead trees to reconstruct summer temperatures in western Norway, when our dendrochronological dating showed the wood to be much older than expected”, says Terje Thun, an associate professor at the Norwegian University of Science and Technology’s (NTNU) Museum of Natural History and Archaeology. Thun conducted the work with his colleague Helene Løvstrand Svarva.
From a time before the Black Death
“We were astounded to find fresh wood in trees that started to grow in the late 1200s and had died almost 500 years ago, which is much older than we originally expected. Somehow they have kept from decomposing for several centuries in this humid climate”, Thun says. “This is quite extraordinary - I would go as far as to call it sensational.”
Thun says that when a pine tree dies, it secretes a great deal of resin, which deters the microorganisms needed for decomposition. “Nevertheless, preventing the natural breakdown of the wood for centuries is quite a feat”, he says. Thun is one on Norway’s leading dendrochronology experts. Dendrochronology is the dating of trees.
Used in mummification
Resin was one of the ingredients used in Ancient Egypt for mummification, so its conservation abilities have been known for millennia. However, that trees could “self-mummify” in such a humid climate for centuries was new to the NTNU scientists.
“Many of the trunks we dated turned out to have seeded in the early 1200s, and had lived for more than 100 years at the time of the Black Death around 1350”, Thun says. “That means that the dead wood has ‘survived’ in nature for more 800 years without breaking down.”
It seems there truly is something good about Norwegian wood.
Helene Lovstrand Svarva is taking samples in Sogndal, Norway. Credits: Terje Thun, NTNU
This tree died in year 1333. Credits: Terje Thun, NTNU
Helene Lovstrand Svarva working in the lab at NTNU. Credits: Terje Thun, NTNU
This three grew from 1334-1513. Credits: Terje Thun, NTNU