The presented studies were carried out in order to check the usefulness of subfossil wood for stable isotope analysis. The aim of research was also to define the optimal method of subfossil samples preparation. Subfossil samples used during the presented studies are a part of the multicentury dendrochronological scale. This chronology originates in an area situated around a small mountain lake — Schwarzersee, in Austria. The obtained results of stable carbon isotope measurements confirmed that the method of α-cellulose extraction by the application of acidic sodium chlorite and sodium hydroxide solutions removes resins and other mobile compounds from wood. Therefore, in the case of the analysed samples, the additional chemical process of extractives removing was found to be unnecessary. Studied wood samples contained an adequate proportion of α-cellulose similar to the values characteristic for the contemporary trees. This proved an adequate wood preservation which is essential for the conduction of isotopic research.

This paper presents a multi-century, maximum latewood density (MXD) chronology developed from living and sub-fossil spruce trees from the Eastern Alps. The chronology is continuous from 88AD to 2008AD. This time series has been analysed with respect to its possible use for climate reconstruction. Correlations with climatic data showed strong dependence between MXD of growth rings and temperature of April, May, June, July, August and September and a weaker, negative dependence with precipitation of May and September. For solar radiation a positive relationship was noted for April, July, August and September. Light rings were frequently observed within the analysed samples and the climate of years with light rings was examined. Mean monthly temperatures in January, June, August, September and October, averaged during light ring years, were cooler than during years without light rings. Precipitation was also significantly reduced in March during light ring years. In turn, solar radiation during light ring years has significantly lowered values in February and August. The occurrence of light rings was often positively related to strong volcanic events.

Accelerator mass spectrometry (AMS) is a worldwide recognized method for radiocarbon (¹⁴C) dating. The advantageous aspects of this method include the variety of materials and the small sample size (1 mg of carbon) that can be measured. However, these pose several challenges in the laboratory, such as developing appropriate chemical pretreatment methods. In the summer of 2022, the Radiocarbon and Mass Spectrometry Laboratory in Gliwice, Poland, launched the MICADAS accelerator spectrometer. The report on background and reference materials measurement results for the period from September 2022 to July 2024 is presented in this publication. Quality assurance and quality control processes are extremely important to guarantee the high quality of the results obtained in the laboratory. Hence, our Radiocarbon and Mass Spectrometry Laboratory in Gliwice took part in the Glasgow International Radiocarbon Inter-Comparison (GIRI) program. The radiocarbon ages for wood, bone, humic acid, and barley mash samples were determined and compared with reported values. The resulting data confirmed that our Laboratory is capable of dating samples across a spectrum of materials and ages ranging from contemporary to the limits of the radiocarbon method, achieving precision on par with that of other laboratories.

The processing of subfossil wood poses some difficulties in densitometric research. Problems arise because of the physiochemical changes of wood occurring in the sedimentation environment. Subfossil wood modification can result from the uptake of mineral and organic substances into the wood tissue. It can also occur as the effect of microbiological degradation of wood. The goal of this study was to identify the appropriate method of subfossil wood preparation for the densitometric research. For this purpose the wood of Norway spruce from Lake Schwarzensee was subjected to extraction in de-ionized water, acetone and diluted acetic acid. The application of acetic acid did not significantly influence the density of the wood and acetone seemed to be too aggressive. The best result was obtained by rinsing the samples in cold de-ionized water. This extraction procedure allowed removal of unwanted water-soluble, organic and inorganic compounds from wood and simultaneously did not lead to the degradation of subfossil samples.

Wasted tires are the great source of fuel and valuable components but could be a cause of environmental and land pollution. This study shows the detailed method for the determination of radiocarbon isotope (¹⁴C) concentration in tires and their pyrolysis products. Samples are taken from truck and passenger car tires in the form of shredded rubber, pyrolysis oil and recovered carbon black. Liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS) techniques were used for the investigation at Gliwice Radiocarbon and Mass Spectrometry Laboratory, and National Laboratory for Age Determination, Trondheim, Norway. The results are in good agreement. Radiocarbon concentration of the rubber varies significantly because of its complex structure and composition within the tires. The ¹⁴C concentration values were found to be higher in pyrolytic oil compared to rubber, and greater in truck tires rather than car tires.