Kozlov V. A., Shapchenkova O. A., Loskutov S. R., Plyashechnik M. A., Aniskina A. A., Permyakova G. V., Neronova Y. A. Destruction of Scots Pine Wood After a Long Exposure to Anaerobic Conditions
How to cite: Kozlov V. A.1, Shapchenkova O. A.2, Loskutov S. R.2, Plyashechnik M. A.2, Aniskina A. A.2, Permyakova G. V.2, Neronova Y. A.1 Destruction of Scots pine wood after a long exposure to anaerobic conditions // Sibirskij Lesnoj Zurnal (Sib. J. For. Sci.). 2019. N. 5. P. 99–108 (in Russian with English abstract).
© Kozlov V. A., Shapchenkova O. A., Loskutov S. R., Plyashechnik M. A., Aniskina A. A., Permyakova G. V., Neronova Y. A., 2019
The wood of Scots pine after 100-600-year exposure to anaerobic conditions was studied. The samples were taken from the soil during archaeological excavations in the city of Veliky Novgorod. It has been established that the destruction of the secondary wall layers (mainly S2 layer) of tracheids in the sapwood and heartwood occurred after 100 and 400 years of exposure, respectively. Archaeological wood contained mineral particles consisting of water-insoluble compounds of iron and potassium. The results of thermogravimetry showed the changes in the relative content of hemicelluloses, cellulose and lignin in the samples of archaeological wood. The proportion of hemicelluloses and cellulose in wood decreased by 8-13 % and the proportion of lignin increased by 6-9 % under the prolonged exposure to anaerobic conditions (400 and 600 years) compared to the samples of 100 and 200-year exposure. This was also confirmed by chemical analysis data. The oxidative thermal decomposition of the carbohydrate complex, as well as lignin started at lower temperatures indicating lower thermal stability of the main components of the wood substance. All the studied wood samples were characterized by a significantly higher proportion of residual mass after thermal decomposition compared to sound wood. This fact also suggested higher content of mineral substances. The total thermal effect of oxidative thermal decomposition of carbohydrate and aromatic components of the wood substance was noticeably higher (13.1 and 12.6 kJ x g-1) for the samples of 400 and 600-year exposure compared to those of 100 and 200-year exposure (8.9 and 10.8 kJ x g-1). Mono-and sesquiterpenes were found in wood, as well as diterpen 18-norabietan, the most resistant one to biological degradation, which accounted for 30-64 % of the total content of volatile organic substances. The obtained results indicated significant changes in the composition and structure of Scots pine wood after 400 years of exposure to anaerobic conditions.