Sapwood Rings Research Articles

European larch sapwood: A model for predicting the cambial age and for a more accurate dating

European larch (Larix decidua Mill.) holds significant importance as a forest tree species throughout the Alps and in certain regions of central Europe. Its extensive use as construction timber has made it a subject of substantial interest in dendroarchaeological studies aimed at understanding the long-term interactions between human societies and forests. Precise dating of felling phases, accurate estimation of the age of harvested wood, and information on the geographical origin of wood play a crucial role when it comes to characterize these interactions. In this study, we compiled a large dataset of L. decidua samples from across the European Alps to provide a robust statistical model that predicts the cambial age of L. decidua trees based on the number of heartwood rings. By extension, this model can be used to estimate the number of sapwood rings so as to approximate the felling date and to more precise date archaeological larch timber. The model requires almost complete heartwood sequences (<5 missing rings) to achieve accurate estimations. Our results also evidence that the ratio between the number of sapwood and heartwood rings varies across the Alps. At the same time, the indicator developed in this work is not suitable for a determination of wood origin, raising doubts about the effectiveness of attempts aimed at dendroprovenancing L. decidua based on sapwood.

A Review of the Factors Influencing Variations in the Heartwood Proportion for Solid Wood

Using 146 journals, 6 chapters, 4 reports, 2 books, and a proceeding, this research seeks to investigate the factors that influence variations in the proportion of heartwood. The data were collected through an online search in databases such as Scopus, Science Citation Index, Science Direct, Google Scholar, and ResearchGate with seven search queries, namely heartwood variability, heartwood proportion, tree age of heartwood, growth rate of heartwood, silvicultural treatment of heartwood, as well as genetic and environmental effects of heartwood. By eliminating papers that were out of topic or title, purpose and year of publication, 67 journal articles, 4 chapters, 3 reports, a book, and a proceeding were selected. The review results showed that the amount of heartwood was influenced by its position in the tree, tree variations, such as age, growth rate, and species/genera, as well as the growing conditions, including location and environmental factors. It is also affected by various silvicultural treatments, namely spacing, thinning, pruning, fertilization, and irrigation. These findings indicate that the amount of heartwood is more controlled by the diameter of the wood than the age. Furthermore, several studies reported that the growth rate of sapwood rings was significantly higher than the heartwood rings, which can reduce the quality of solid wood used for construction. Therefore, it is necessary to control the proportion of heartwood through genetics and environmental factors, especially genetics, which has more effects on the growth rate of tree diameter than environmental factors. Previous studies revealed that tree diameter has a weak or negative correlation with other wood properties, such as basic density, color, and wood stiffness, which are generally important in global markets. It is important for breeders to concentrate on using species with superior genetic variations as well, especially the highly demanded traits in further studies.

Axial conduit widening, tree height and height growth rate set the hydraulic transition of sapwood into heartwood.

The size-related xylem adjustments required to maintain a constant leaf-specific sapwood conductance (KLEAF) with increasing height (H) are still under discussion. Alternative hypotheses are that: (i) the conduit hydraulic diameter (Dh) at any position in the stem and/or (ii) the number of sapwood rings at stem base (NSWr) increase with H. In addition, (iii) reduced stem elongation (ΔH) increases the tip-to-base conductance through inner xylem rings, thus possibly the NSWr contributing to KLEAF. A detailed stem analysis showed that Dh increased with the distance from the ring apex (DCA) in all rings of a P. abies and a F. sylvatica tree. Net of DCA effect, Dh did not increase with H. Using sapwood traits from a global dataset, NSWr increased with H, decreased with ΔH, and the mean sapwood ring width (SWrw) increased with ΔH. A numerical model based on anatomical patterns predicted the effects of H and ΔH on the conductance of inner xylem rings. Results suggested the sapwood/heartwood transition depends on both H and ΔH, and is set when the C allocation to maintenance respiration of living cells in inner sapwood rings produces a lower gain in total conductance than investing the same C in new vascular conduits.

Variability of activity concentrations and radial distributions of 137Cs and 90Sr in trunk wood of Scots pine and Silver birch

This study analyzes the variability of 137Cs and 90Sr concentrations in wood and their radial distributions in the trunks of Scots pine and Silver birch trees in the small uniformly contaminated forest stands in the Chornobyl Exclusion Zone. Concentrations of both radionuclides follow a lognormal distribution with a large scatter of values measured in the trees within the stands (GSD ranges from 1.6 to 2.0). No correlation was found between the concentrations of the two radionuclides measured in individual trees, or between their concentrations and tree diameter. The average 137Cs and 90Sr Tag were 8.4 × 10−4 m2 kg−1 and 8.8 × 10−3 m2 kg−1 for pine, respectively, and 9.3 × 10−4 m2 kg−1 and 1.1 × 10−2 m2 kg−1 for birch, indicating a much higher availability of 90Sr for uptake by the studied species. For 137Cs, the Tag values are within the range recommended by the IAEA Handbook (IAEA, 2010), while the values for 90Sr exceed the recommended range for birch and are close to its upper value for pine.The highest concentrations of 137Cs in pine at the height of 1.3 m were measured in the youngest sapwood rings; they were lower in the rest of the sapwood and decreased further in the heartwood, but remained relatively high even in annual rings that were the heartwood at the time of deposition, suggesting sapwood-to-heartwood translocation of the radionuclide by diffusion and/or ray transport. In contrast, 90Sr concentrations increased through the sapwood from the trunk periphery in pine trees up to 80 years old and remained stable through the sapwood in older trees (except for higher concentrations in the young annual rings), but dropped to zero in physiologically inactive heartwood tissues. In most birch trees, regardless of age, 137Cs concentrations demonstrated an increasing trend from the trunk periphery towards the pith, while concentrations of 90Sr were relatively stable in the whole trunk except in the oldest annual rings, where they increased sharply, likely indicating active transport of the radionuclide to senescing tissues.

Aging mulberry trees (Morus nigra L): The Charterhouse, London, UK

ABSTRACT Black or Common Mulberry (Morus nigra) was introduced into Britain in the late sixteenth – early seventeenth centuries and has since had limited success as an ornamental and fruit-producing tree. Older specimens survive in a limited number of locations including at The Charterhouse in central London. Four of these trees were investigated with the aid of standard dendrochronological techniques, historic images, including an early postcard and a painting by Edward Ardizzone, and with the application of expert knowledge of the forms and ages of contemporary mulberry trees. Results included the creation of a new ring-width chronology (CH_Mulberry) and dating that suggests the two oldest trees may well have been planted to commemorate either Queen Victoria’s Golden (AD 1887) or Diamond Jubilee (AD 1897). The research represents a first known dendrochronological investigation of the species, highlighting issues associated with sampling “tortuous” growth forms and the poor visibility of sapwood rings, as well as the potential for the use of branch ring-widths to facilitate dendrochronological dating of fruit and other trees.

A statistical model for the prediction of the number of sapwood rings in Scots pine (Pinus sylvestris L.)

Dendrochronology is a well-established dating method for wooden objects, but due to surface processing of construction timber or natural degradation the dating of historical wood often relies on a prediction of the number of missing rings based on sapwood statistics. Since Scots pine (Pinus sylvestris L.) is one of the most common tree species in north-western Europe, the absence of reliable sapwood statistics and models for the prediction of missing sapwood rings for pine samples is remarkable. We have therefore produced sapwood statistics based on data from 776 pine trees with ages from 15 to 345 years. The material consists of both living trees and historical timber, with varying growth rates, geographic settings, and from different soil types. When the whole material is considered, the average age of the trees is 103 years, and the number of sapwood rings is 54 ± 15 (1 SD), but range from 18 to 129. Trees less than 100-years in age contained 46 ± 11 (1 SD) sapwood rings and had an average tree-ring width (TRW) of 1.76 mm. With increasing age, the average TRW decreased while the number of sapwood rings increased. The average TRW of 101–200-year-old trees is 0.99 mm while the samples contained 63 ± 12 (1 SD) sapwood rings. For trees older than 201 years, the average TRW is 0.64 mm while the number of sapwood rings increased to 85 ± 16 (1 SD). The two most important factors in determining the number of sapwood rings for a given tree when only heartwood statistics are available proved to be (i) the number of heartwood rings and (ii) the average TRW of the heartwood rings. For incomplete samples, we have therefore developed a statistical model based on the sample’s heartwood rings (number and average width) to compute a prediction interval for the total number of rings. The sapwood and heartwood statistics suggest a statistical model for the number of sapwood rings with mean that increase with the number of heartwood rings. Furthermore, the average number of sapwood rings decreases with the mean width of the heartwood rings. However, the predictive power of the mean width is limited when the number of heartwood rings has already been taken into account. Thus, we suggest making predictions for the number of sapwood rings using only the number of heartwood rings. Predictions of the number of sapwood rings based on the statistical model where convincing in the case of the three different datasets that were analysed. The certainty in these predictions was such that the width of the 80% and 95% prediction intervals ranged 28–34 and 45–52 sapwood rings, respectively. Additionally, we demonstrate how make predictions when there is information about the number of remaining sapwood rings in a given sample. To make the sapwood model available, we present a free online R package for fitting our models and an online software dashboard.

Absolute Age Determinations of Rural Basque Furniture Using Dendrochronology: A Pilot Study of Four Granary Chests and a Wardrobe

Dendrochronological research in NW Spain is aimed at developing reference chronologies of oak (Quercus sp.), which are suitable for absolute age determinations of cultural heritage from the Basque Country. So far, the main research interest has been on rural architecture such as farmhouses and barns. In order to extend the application range of Basque dendrochronology, the current study focuses on tree-ring research of rural furniture. In close consultation with the curators of cultural centre Gordailu (Irun), four granary chests and a wardrobe were selected for this pilot study. The tree-ring patterns of these objects significantly match against the new Basque reference chronologies, yielding absolute calendar years for the studied panels. The last-formed measured ring from the oldest granary chest in this collection dates to AD 1517. The other three chests have last-formed rings dating to AD 1580, 1665 and 1829, and the wardrobe has a last-formed ring dating to AD 1439. Sapwood ring counts from living oaks in this region were used to estimate the number of sapwood rings missing on the outside of the panels. Derived absolute and terminus post quem felling dates of wood were further refined by adding the estimated drying time of the wood based on information derived from traditional carpenters in this area. All dendrochronologically established construction dates constitute a correction or refinement of the original art-historical age determinations. In addition, the previously assigned provenance of one granary chest could be corrected. These results indicate that dendrochronology is an excellent method to refine our knowledge about the age, and in some cases the exact geographical provenance, of rural movable heritage in and from the Basque region. The fact that the previously established provenance of four of the studied objects within the Basque Country could not be refined further implies that most Basque reference chronologies at present are not sufficiently specific for assessing wood provenance on an intra-regional scale. This can be solved in the future by reassembling the data underlying these chronologies into homogeneous timber groups covering smaller, ecologically more similar, geographical growth areas.

Woodland Management Practices in Bronze Age, Bruszczewo, Poland

The article presents a study of wood excavated from archaeological site in Poland (2100–1650 BC). The large amount of collected samples created a unique opportunity for research because the subfossil wood was in very good preservation state. This made it possible to carry out dendrotypological analysis. This is the first such study conducted for Early Bronze Age timber originating from Poland. The main goal of the study was to determine whether the presence of strong and abrupt reductions and releases of growth, observed within tree-ring sequences, is due to natural stand dynamics, results from the influence of extreme environmental factors or whether they should be linked to specific silvicultural practices already known in ancient times. Another purpose of the study was to determine the type of forest management techniques applied to the trees growing in Bruszczewo site. The research was conducted using the dendrochronological method. In addition to the measurements of growth-ring width, the development of earlywood and latewood zones, the proportion of sapwood and the presence of specific features of tree trunks were analysed. A detailed study allowed identifying the samples originating from coppiced and shredded trees. A characteristic feature of the trees subjected to these silvicultural practices is the presence of strong and abrupt reductions and releases of growth. Moreover, coppiced trees were specified by the large proportion of sapwood in the cross-section of the stem, reduced number of sapwood rings, small and numerous earlywood vessels, diminished earlywood vessels area. In turn, shredded trees distinguished themselves by a strong reduction in the earlywood width in the years following the shredding event. The research of archaeological wood from the ancient settlement proves that during the Early Bronze Age various forest management techniques were used in this site. These treatments were aimed at improving the quality and quantity of the raw material harvested from forest areas.

Heartwood variations in mid-aged plantations of Erythrophleum fordii

Erythrophleum fordii Oliv. (Caesalpiniaceae) is a rosewood species naturally distributed in southeast Asia and south China, and the heartwood is commonly used for high-quality crafts and furniture. While there are differences in heartwood development among single trees with distinct social status, the relationship between heartwood development and growth performance remains unclear. This information is essential to improve plantation management for high-yield heartwood production. Forty dominant, intermediate and suppressed trees were sampled from E. fordii plantations aged in 32–35 years in Pingxiang City, Guangxi, China. Stem analysis was carried out to determine horizontal and vertical variations of heartwood and sapwood. Number of annual rings, diameter and area of heartwood and sapwood as well as ratios of heartwood diameter and area at breast height were all significantly influenced by the social status of trees in stands (P < 0.05). In these mid-aged plantations, E. fordii stems developed heartwood once the xylem diameter reached 5–10 cm, and then heartwood diameter and area increased with increasing xylem diameter. Heartwood ring numbers, diameter and area as well as their ratios decreased with increasing height, while sapwood ring numbers and diameter were relatively constant within the section where heartwood occurred. Heartwood and sapwood diameters were equal at heights of approximately 6-m for dominant, 5-m for intermediate and 3-m for suppressed trees. Dominant trees differed considerably from intermediate and suppressed trees in heartwood volume, while heartwood volume ratios were all below 30%, and near 90% in the stem section below 8-m height regardless of social status. Relationship analysis showed that DBH was the most important factor influencing heartwood in even-aged stands. The findings provide evidence for crop tree selection, thinning regimes and reasonable management of plantations of E. fordii.

Contrasting tree ring Hg records in two conifer species: Multi-site evidence of species-specific radial translocation effects in Scots pine versus European larch

Tree ring records are increasingly being used as a geochemical archive of past atmospheric mercury (Hg) pollution. However, it is not clear whether all tree species can be used reliably for this purpose. We compared tree-ring Hg records of two coniferous species - widely used Scots pine (Pinus sylvestris) and less frequently used European larch (Larix decidua) at 6 study sites across the Czech Republic. Site-specific mean Hg concentrations in tree-ring segments of larch ranged from 2.1 to 5.2 μg kg−1, whereas pine had higher mean Hg concentrations (3.6–8.3 μg kg−1). Temporal records of Hg concentrations in tree rings of larch and pine differed significantly. Comparisons with previously documented peat Hg records showed that larch tree-ring Hg records more closely agreed with peat archive records. For pines, which had a large, tree-age dependent number of sapwood rings (62 ± 17, 1SD), we found a strong relationship between the year of peak Hg and the number of sapwood tree rings (p = 0.012, r2 = 0.35), as well as between peak Hg year and the sapwood-heartwood boundary year (p < 0.001, r2 = 0.65), rather than with temporal changes in atmospheric Hg levels. The much greater number of pine sapwood tree rings appears to promote radial Hg translocation, resulting in the shift of Hg peaks backward in time through the tree-ring record. In contrast, Larch consistently had a low number of sapwood tree rings (19 ± 6, 1SD), and more closely agreed with peat Hg records. This study suggests that European larch, a tree species characterized by a relatively low and consistent number of sapwood tree rings, records changes in atmospheric Hg concentrations more reliably than does Scots pine, a species with a relatively high and variable number of sapwood tree rings.

The Zurich method for sapwood estimation

We present a new predictor for the estimation of the number of missing sapwood rings in oak. It circumvents a number of problems with predictors used in traditional sapwood estimation procedures such as mean ring width or tree age. Instead, we use the mean ring width of the last 9 heartwood rings and the first sapwood ring, which mirrors the growth level during sapwood formation. We present a model to produce a 95 % prediction interval for the felling year. Our method accounts for the skewed distribution of the number of sapwood rings towards higher values.

ELM Dendrochronology

Elm is generally considered to be unsuitable for dendrochronology, usually having too few rings, or having abrupt growth-rate changes that do not result from the external weather conditions. Samples rarely match each other in the same structure. A further difficulty is that even where it is known that the sequence is complete (the bark is still present), it is often not possible to distinguish sapwood rings by their appearance, even under a microscope. This is a significant problem as elm has been an important structural component of many British vernacular buildings over many centuries, but whereas dendrochronological dating of oak has transformed our understanding of thousands of buildings, by 2015 only four instances of dating elm had been made, two of those involving a single timber. When elm has been encountered, it has generally been dismissed from further dendrochronological study as a result of these known issues, but no systematic study has been undertaken to see whether these prejudices are justified. In order to get some evidence-based information about how elm might behave dendrochronologically, Historic England initiated a study: Developing the dendrochronology of elm in historic buildings, Project 7350, funded through its Heritage Protection Commissions. This resulted in over 70 buildings being looked at, with several being sampled, and the results are discussed here. At some sites an elm site master sequence could be derived, but potential matches with local oak chronologies were generally not strong enough to be considered dated. In one instance good matches with local oak sites were found, but subsequent radiocarbon analysis found these matches to be erroneous. At another site, five trees gave an 89-year ring sequence, but no acceptable matches were found with oak chronologies. Radiocarbon dating and oxygen isotope dating both gave the same dating results at this site, however, showing that these two methods appear to give the best hope of dating elm in the future.

SAPWOOD RINGS ESTIMATION FOR PINUS SYLVESTRIS L. IN LITHUANIA AND LATVIA

Pinus sylvestris L. is the predominant tree species used for wooden constructions in the Baltic area. Accordingly, the timber of Pinus is the most important object for investigation and dating carried out by dendrochronologists of the Baltic countries. However, the dating of historical Pinus is often challenging when the outer sapwood rings are missing in the wood samples. In Pinus, sapwood rings increase in number as the tree ages, and therefore calculating the approximate number of missing outer rings from a set range, a technique used for oak, is not possible. In Norway, a simple method for estimating the number of sapwood rings has been developed for some native species of conifers. The aim of this small-scale study was to assess the validity and the practical suitability of the Norwegian method for estimating the number of missing sapwood rings of mostly historical Pinus wood samples obtained in the southeastern part of the Baltic region. Our findings indicate that this method is not acceptable for estimating the number of missing sapwood rings for individual trees, but suggest that it may be applicable when dating tree-ring chronologies for a minimum of 20 trees, containing individuals up to 200 years old.

Sapwood characteristics of Quercus robur species from the south-western part of the Pannonian Basin

We analysed sapwood characteristics in 344 pedunculate oak (Quercus robur L.) samples from the south-western part of the Pannonian Basin. The samples came from 13 sites, located in Slovenia, Croatia and Serbia. The trees had an average of 13.3 sapwood rings, with a minimum of 5 and maximum of 32. Fifteen log-log linear regression models were employed to assess the statistical relationship between sapwood and heartwood variables. The number of sapwood rings (NSW), which is usually needed in dendroarchaeological dating, is significantly related to the number of heartwood rings (NHW), heartwood width (WHW) and heartwood growth rate (GHW). Older and more slowly growing trees had a higher average number of sapwood rings. Using NHW and WHW, we employed an additional multiple regression model and calculated coefficients for NSW predictions for real-world dendroarchaeological dating from the south-western part of the Pannonian Basin.

Using tree rings to reconstruct changes in soil P availability – Results from forest fertilization trials

Hitherto, there are only few studies that have analysed the variation of P contents in individual tree rings to reconstruct fluctuations in soil P availability. Therefore, this pilot study aimed to assess the relationship between changes in P content in tree rings and known changes in soil P availability resulting from fertilization of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) in fertilization trials at two different sites. We compared P contents in single tree rings from fertilized and unfertilized plots formed before and after P fertilization and assessed (1) whether fertilization leads to an immediate increase in P uptake and higher P contents in tree rings formed after fertilization, and (2) whether P is translocated to older tree rings that were formed before fertilization.After application of 70 kg P ha−1, a prompt and extended increase in relative wood P contents could be observed in both Norway spruce and Scots pine. However, only at the Norway Spruce site, this increase could be properly assigned to a P fertilization signal in heartwood rings formed after fertilization. In sapwood rings, however, P fertilization signals were masked by the inherent increase in P content from older towards younger sapwood rings, which was at least one order of magnitude higher than the increase from fertilization. We could not observe a P translocation into older tree rings, which existed as sapwood rings at the time of fertilization.This pilot study underlines the potential of dendrochemistry for reconstructing changes in soil P availability and improves the conceptual basis for further dendrochemical research, not only in fertilized but also in unfertilized forest ecosystems.

A 781-year oak tree-ring chronology for the Middle Ages archaeological dating in Maramureș (Eastern Europe)

From 1997 to the present, a sustained project in the Maramureș region in Romania was completed with the construction of a 781-year oak tree-ring chronology. A total of 395 samples from living trees and 429 from archaeological wood were analysed with dendrochronological methods. The study aimed to provide the scientific community with a new oak chronology that could be applied in dendroarchaeology, dendroclimatology and dendroecology studies and also for interpreting past socio-economic events. Furthermore, we studied the number of sapwood rings and the growth pattern for different time periods. The chronology covered the continuous period of A.D. 1236‒2016. From the 824 samples collected, we separated 271 tree-ring series into a new chronology (A.D. 1406–2016), which fulfilled all the criteria necessary to reconstruct past climate and environmental changes. The resulting new tree-ring chronology indicated robust signal series intercorrelation (r = 0.55) and an average mean sensitivity of 0.21. Based on an analysis of the sapwood, we recommend estimating a number between 8 and 32 rings to the date of final ring for 95% confidence range of mean on the for felling in the Maramureș region. Additionally, we observed that the number of sapwood rings was not correlated with altitude or oak tree species.

Differences in the viscoelastic properties between earlywood and latewood in the growth rings of Chinese fir as analyzed by dynamic mechanical analysis (DMA) in the temperature range between −120°C and 120°C

Abstract To clarify the viscoelasticity of earlywood (EW) and latewood (LW) within different growth rings of Chinese fir, the following data were determined: absolute dry density, percentage of tracheid cell wall, microfibril angle (MFA), modulus of elasticity (MOE), storage modulus (E′) and loss modulus (E″) within the 3rd and 6th growth rings (in heartwood, hW) and the 14th and 18th growth rings (in sapwood, sW). The E′ and E″ data were obtained by dynamic mechanical analysis (DMA) between −120°C and 120°C, at a heating rate of 1°C min−1 at the frequencies of 1, 2, 5 and 10 Hz under a dynamic load amplitude of 10 μm. All measured data were different between EW and LW. In the same growth ring, LW had a greater MOE and larger E′ than those of EW due to the higher density of LW. The MOE and E′ increased for both EW and LW with increasing tree age. The variation of MFA in different growth rings of EW influenced the MOE and E′. Both density and the MFA affected the MOE and E′ in LW. The profiles of E″ plots vs. DMA temperature reveal two maxima around −12°C (β mechanical relaxation process, βMRP) and 12°C (αMRP). The LW-MRP maxima are higher than those of EW, but in both cases increased with tree age. No frequency dependence was seen for the αMRP, whereas the loss peak temperature (LPT) of the βMRP increased with increasing frequency of DMA. Almost no difference in αLPT was observed between the four EW growth rings, and their βLPTs were similar. The LW-αLPT was almost the same in the four growth rings, but the hW-βLPT was higher than that of sW. In addition, the apparent activation energy (ΔH) of the hW-βMRP was greater than that of sW in both EW and LW, and the EW data&gt;LW data in individual growth rings. These differences can be explained tentatively that hW and EW contain more extractives than sW and LW, and the deposited of extractives limit the motion of molecular segments within the cell walls.

Variation of Ring Width and Wood Density in Two Unmanaged Stands of the Mediterranean Oak Quercus faginea

Ring width and wood density variation were studied from pith-to-bark and along the stem in two naturally regenerated stands of Quercus faginea Lam. in Portugal. Ring width was significantly different between sites, in both heartwood and sapwood rings, ranging from 1.83 mm to 2.52 mm and from 0.77 mm to 2.11 mm, respectively. Wood density was significantly different between sites only in the heartwood, i.e., 914 kg m−3 and 1037 kg m−3. Site effects were the main source of variation for ring width and wood density within the heartwood as well as for sapwood ring width, while the between-tree effects explained more the density variation within the sapwood. Wood density showed within-tree uniformity that was not affected by site. The stand characteristics such as basal area and tree age may override the environmental growth conditions. There was also a weak correlation between wood density and ring width components therefore suggesting the possibility of forestry management for both fast tree growth and high wood density.

Updating the Czech Millennia-Long Oak Tree-Ring Width Chronology

ABSTRACT In recent years, a millennia-long oak tree-ring width chronology, consisting of 3194 samples from 387 locations, was developed in the Czech Republic. Despite the collection of such a huge dataset, the replication in the 19th Century was very low and the natural oak distribution in the Czech Republic was insufficiently covered by recent samples, especially in Western Bohemia. This study aimed to remove these weaknesses, which have limited the paleoclimatic potential of this dataset, and to determine the number of sapwood rings, which is crucial for dendrochronological dating. Therefore, new recent samples were randomly collected at numerous sawmills along the Czech-German border. The historical material was usually sampled using a Pressler borer from church belfry constructions traditionally made from oak. In total, 252 recent and 90 historical tree-ring width series were incorporated into the chronology. The newly built chronology cumulatively consists of 3536 series, which covers the continuous ...

TREE-RING DATE LISTS 2014

Dates of outermost measured complete rings and sapwood ring number are given in brackets. Complete sapwood is indicated by ‘C’ and where the character of the final ring has been identified, some la...