High-Throughput DNA sequencing of ancient wood.

Reconstructing the colonization and demographic dynamics that gave rise to extant forests is essential to forecasts of forest responses to environmental changes. Classical approaches to map how population of trees changed through space and time largely rely on pollen distribution patterns, with only a limited number of studies exploiting DNA molecules preserved in wooden tree archaeological and subfossil remains. Here, we advance such analyses by applying high-throughput (HTS) DNA sequencing to wood archaeological and subfossil material for the first time, using a comprehensive sample of 167 European white oak waterlogged remains spanning a large temporal (from 550 to 9,800 years) and geographical range across Europe. The successful characterization of the endogenous DNA and exogenous microbial DNA of 140 (~83%) samples helped the identification of environmental conditions favouring long-term DNA preservation in wood remains, and started to unveil the first trends in the DNA decay process in wood material. Additionally, the maternally inherited chloroplast haplotypes of 21 samples from three periods of forest human-induced use (Neolithic, Bronze Age and Middle Ages) were found to be consistent with those of modern populations growing in the same geographic areas. Our work paves the way for further studies aiming at using ancient DNA preserved in wood to reconstruct the micro-evolutionary response of trees to climate change and human forest management.

Too early and too northerly: evidence of temperate trees in northern Central Europe during the Younger Dryas.

This paper presents highly unexpected paleobotanical data. Eight (14) C-accelerator mass spectrometry (AMS) dates of soil macrocharcoal pieces, identified taxonomically, indicate the presence of oak and beech in the Younger Dryas, and pine in the Allerød, in the northernmost low mountain range of Central Europe, the Harz Mountains, in Germany. If the presence of pine at such latitude and periods is not surprising, the presence of temperate-adapted trees is highly improbable, because they are assumed to have reached the area from a southern location several thousand years later. Two hypotheses are postulated to explain this record. Both are related to the warm periods of the Bølling and Allerød: the classically 'short' duration of this warm period makes the migration of the temperate trees from the identified refuge areas in the southern location implausible, and so the presence of intermediary microrefugia at a medium latitude in Central Europe is postulated; recent data reveal that the warm period of the Late Glacial phase was much longer than considered in the classical view and, thus, would be long enough for a northward migration of temperate-adapted trees. Although our dataset does not permit disentanglement of these hypotheses, it provides significant innovative insights for the biogeography of Central Europe.

Network for forest by-products charcoal, resin, tar, potash (COST Action EU-PoTaRCh).

The COST EU-PoTaRCh Action establishes a network focused on the past, present, and future significance, production, and use of major forest by-products in Europe and beyond. The Action centers around forest by-products-primarily potash, tar, resin, and charcoal (PoTaRCh), along with plant extracts-which have been produced and utilized for over 100,000 years due to their unique chemical, biological, and therapeutic properties. The primary goal of the Action is to demonstrate the importance of these products for the socio-economic development of European countries and beyond, as well as their impact on biodiversity and the natural environment. The Action's objectives are organized into five Working Groups (WGs), each aligned with specific areas of interest: heritage, chemical characterization, archaeology, environmental history, and future perspectives of PoTaRCh materials. A key aspect of the Action is its support for stakeholders outside the scientific community who possess knowledge of PoTaRCh products through their use in industries such as production, education, and the promotion of forests' natural and cultural heritage. In doing so, the Action brings together stakeholders with diverse activity profiles, including museums, state forests, the forestry industry, associations dedicated to preserving traditions, and the tourism sector. The EU-PoTaRCh Action adheres to the three key principles of COST's inclusiveness policy: participation of inclusiveness target countries, gender balance, and the involvement of young researchers, including in leadership positions.

The COST EU-PoTaRCh Action was established to gather information on the past, present, and future significance, production, and use of major forest by-products in Europe and beyond. These products include potash, tar, resin, and charcoal (PoTaRCh), as well as plant extracts. They have played a crucial role on both a micro scale, affecting the daily lives of individuals, and a macro scale, influencing socio-economic parameters and the natural environment. Given the extensive scope and historical depth of PoTaRCh production and use (with tar production dating back 100,000 years), knowledge on this subject across Europe and beyond is dispersed and highly diverse. The aim of the Action is to consolidate this information and enhance awareness of the importance of PoTaRCh products. A key aspect of the Action is supporting stakeholders who possess knowledge of PoTaRCh products and are interested in their application in production, education, and the promotion of forest natural and cultural heritage. The Action brings together partners with varied activity profiles, including museums, state forests, the forest industry, associations dedicated to preserving traditions, the tourism industry, and the scientific community. EU-PoTaRCh adheres to three key principles of COST's inclusiveness policy: participation of Inclusiveness Target Countries (ITCs), gender balance, and the involvement of young researchers (YRs), including in leadership positions.

Micro-computed tomography for the identification and characterization of archaeological lime bark.

In the Neolithic pile-dwelling settlements of southwestern Germany, bark played a prominent role in the production of technical textiles. So far, the inner bark (phloem) of the lime tree (genus Tilia) could be detected most frequently. Microscopic examination of anatomical features can determine the taxon, requiring manipulation of samples and archaeological objects. In this study, micro-computed tomography (µCT) was reviewed as a method for determining the woody taxon and obtaining additional information from the inner bark. To this end, modern bark samples from different tree organs of lime were first analysed using both µCT and transmitted light microscopy. Both methods were able to detect all characteristic anatomical features in the phloem and identify the genus. With analysis based on µCT data, further anatomical information can be obtained. For example, the shape of the phloem rays in the bast strips can provide information on the position within the bark and on the original organ diameter. These results obtained on modern material were verified on four samples from archaeological objects. Based on µCT, all samples could be clearly identified as lime and in two cases conclusions could also be drawn about the raw material. This approach could lead to new results and interpretations in archaeological sciences.

Acceleration of Biochar Surface Oxidation during Composting?

Biochar composting experiments were performed to determine whether composting is a suitable method to accelerate biochar surface oxidation for increasing its reactivity. To assess the results, surface properties of Terra Preta (Brazil) and ancient charcoal pit (Northern Italy) biochars were additionally investigated. Calculation of O/C ratios by energy-dispersive X-ray spectroscopy demonstrated the anticipated increasing values from fresh biochars (0.13) to composted biochars (0.40), and finally charcoal pit biochars (0.54) and ancient Terra Preta biochars (0.64). By means of Fourier transformation infrared microscopy, formation of carboxylic and phenolic groups on biochars surface could be detected. Carboxylic acids of three composted biochars increased up to 14%, whereas one composted biochar showed a 21% lower proportion of carboxylic acids compared to the corresponding fresh biochar. Phenolic groups increased by 23% for the last mentioned biochar, and on all other biochars phenolic groups decreased up to 22%. Results showed that biochar surface oxidation can be accelerated through composting but still far away from ancient biochars.