Dendrochronologia最新文献

The olive tree is an iconic component of Mediterranean agricultural landscapes. Many monumental olive trees are regarded as millennial individuals, but their ages cannot be estimated through tree ring dating. Alternatively, ¹⁴C-dating of pith wood sample provides age estimates for these old trees. However, published age estimates indicate that most ages of old olive trees range between 200 and 700 years. Nevertheless, some rare individuals may be millennial or even older. Here we report the oldest dated olive tree, sampled in the so-called Noah olive grove in Bshaaleh (northern Lebanon), and having an age of 1161 ± 131 years according to ¹⁴C dating. By measuring tree diameter, ring counting, and ¹⁴C wood dating in old olive trees in Mediterranean countries an equation was obtained to estimate the ¹⁴C-estimated age of old olive trees: age = 37.56 + 1.835 diameter. We conclude that most monumental olive trees are centennial but not millennial, with very old trees probably restricted to harsh sites where trees show slow growth rates.

Instruments aiming to avoid illegal logging such as certification chains require data-driven solutions to verify timber origin. One approach to timber tracing is dendroprovenancing, which uses the spatial and temporal consistency of tree ring width patterns to match unknown samples to reference samples from known locations. Best matching reference samples indicate the potential source location of the unknown sample. Gaps in temporal and spatial coverage of reference chronologies however currently limit applicability of dendroprovenancing, with additional data acquisition being both time-consuming and expensive. This study presents a novel general dendroprovenancing framework, aiming to overcome this shortcoming. It relies on modelling and spatially exhaustive prediction of reference chronologies using a regression model and gridded high-resolution soil- and climate data with global coverage. The presented framework is explored through a case study on Quercus robur using 107 tree-ring chronologies from western and central Europe. We tested three scenarios using leave one out cross-validation: 1) the dating of the chronology is unknown, 2) the source location of the chronology is unknown, and 3) both the dating and source location of the chronology are unknown, with the latter most closely resembling a real-world scenario. We found that tracing accuracy was high, even in the scenario in which both the dating and source location of the chronology were unknown. 82.2% of the chronologies were traced to within a radius of 250 kilometres from the ground truth and correctly dated. The findings highlight newfound potential of dendroprovenancing for timber tracing.

In drought studies based on tree-ring data, there is currently no unified drought index that can capture the drought signals contained in tree rings from different climates, habitats, and species. This makes it difficult to compare the results of numerous studies. This paper compared data charactering wet and dry variations in the Ulan Buh Desert in northwestern China from 1962 to 2017, as indicated by different drought indices. We selected the most commonly used drought indices in tree-ring research: precipitation (Pre), self-calibrating Palmer aridity index (scPDSI), and standardized precipitation evapotranspiration index (SPEI), based on observed meteorological data (-obs) and grid data from the Climatic Research Unit (-cru). The results showed that although the different drought indices were significantly correlated with each other, they showed different linear trends. Correlation analyses with the tree-ring width chronology in the study area showed that the applicability of drought indices based on observed data was better than that of drought indices based on CRU data. The correlation between SPEI-cru and chronology was much lower than that of SPEI-obs, scPDSI-obs, scPDSI-cru, Pre-obs and Pre-cru. The extreme drought years identified by SPEI-cru also differed from other indices. These results suggest that SPEI-cru is not applicable to dendrochronological studies in the Ulan Buh Desert, mainly due to the differences between the CRU data and the measured data, and the high sensitivity of SPEI to potential evapotranspiration. This case study illustrates that tree-ring based drought studies must be based on an assessment of the applicability of different drought indices.

China’s north–south climatic transitional zone, the Qinling–Bashan Mountains (QBM), is sensitive to climate change. In this paper, we present a new tree-ring width chronology derived from a Pinus henryi Mast. from the southwestern part of the QBM and demonstrate that ring width was limited by the mean summer minimum temperature between 3 May and 20 July of the previous year (r = 0.68, p < 0.001). The start and end dates of this limiting period are close to the Beginning of Summer (5–7 May) and the Greater Heat (22–24 July), respectively, of the Chinese Twenty-four Solar Terms, which are important for plant growth. We reconstructed the minimum summer temperatures in the study area since 1879 AD and found four cold periods (1879–1891, 1926–1951, 1966–1980, and 1988–1999 AD) and three warm periods (1911–1916, 1956–1962, and 2004–2010 AD). This new reconstruction not only reveals strong local climate signals but was also able to capture large-scale temperature events. The results of multi-taper spectral analysis, cross wavelet transforms, wavelet coherence analysis, and spatial correlation analysis indicate that summer temperature variations in the QBM are associated with solar activity, the El Niño-southern oscillation (ENSO), the Pacific decadal oscillation (PDO), and the Atlantic multidecadal oscillation (AMO). Our Geodetector results indicate that the combined impact of these drivers on temperature variations is much stronger than that of each individual driver, and they especially emphasize the significant impact of the interaction between the PDO and AMO on temperature variability in the study area.

Blue intensity (BI) has emerged as an inexpensive and relatively simple method for obtaining a proxy for relative wood density, and it has been successfully tested on several conifer species in Europe, North America, Asia and Australasia. Despite international efforts to promote the use of these methods worldwide, BI chronologies developed for native South American species have not yet been published. The possibility of developing BI chronologies in Araucaria araucana, an emblematic conifer of northern Patagonia, began to be explored some years ago. However, as it has been reported in other species, the wood anatomy of Araucaria presents several difficulties for obtaining robust BI common signals between samples. Therefore, we conducted this study to assess various methods for determining BI parameters based on the degree of common signal between trees in the chronology and their correlation with climatic factors. In this study, we demonstrated the feasibility of developing reliable BI chronologies from a site within the Araucaria range in Argentina by analysing the sensitivity to changes in the width of the measurement window. Although replicating measurements within the same core improved the classical statistic used to quantify the expressed population signal in a chronology (i.e. EPS), the results obtained here show that the chronologies developed using different methods were practically identical. Furthermore, our results revealed different climate signals expressed by both earlywood (EWBI) and latewood (LWBI) BI records, corresponding to the current spring and summer, respectively. In addition, soil water availability was significantly associated with wood density variation. Therefore, the climatic and environmental information provided by BI measurements in Araucaria complements what is already known from ring width (RW) and thus highlights its potential for use in future climate and ecological reconstructions.

Better insights into spatio-temporal climate signals are needed to understand more clearly the applicability to palaeoclimatic analysis and dendrochronological dating of the long tree-ring oak chronologies currently being compiled in Eastern Europe. This study investigates the climate sensitivity of two recent oak tree-ring width (TRW) chronologies from Transcarpathian and Ciscarpathian Ukraine and their coherence with 35 oak chronologies from Ukraine, Poland, Slovakia, Romania, and Hungary. The new Transcarpathian chronology consists of 247 TRW series of living trees from 13 sites covering the period 1836–2020, while the new Ciscarpathian chronology consists of 215 TRW series from 13 sites and spans the period 1775–2020. Despite the strong similarity between these two chronologies, their responses to climate differ significantly. Growing-season precipitation and particularly drought (three-month SPEI index) were found to be the primary drivers of oak growth on the border between the Carpathians and the northeastern Pannonian Basin. Spatial correlations of the Transcarpathian chronology show particularly high explained variability in the April-August SPEI index, roughly between 18.5–28.5°E and 45–52°N. In the Ciscarpathian, June precipitation primarily influenced oak radial growth but the spatial correlation was quite low. While the Transcarpathian TRW chronology was strongly correlated with eastern Slovakian and northwestern Romanian chronologies, the Ciscarpathian chronology revealed very low correlations with surrounding chronologies. This study indicates the great dendroarchaeological and palaeoclimatic potential of the Transcarpathian chronology and points to the need to analyse additional living trees from the Ciscarpathian region to understand the spatial variability of oak growth and its climate signal better.

Managing forest ecosystems at global scale is a pressing challenge for resource managers and it needs to address important questions on continuous monitoring. Advance in information technology and in the use of multifunctional devices based on Internet of Things (IoT) technology, for real time observation of biological and physical variable of trees is getting more and more common in modern forestry. Among the different smart sensor networks, the Tree Talkers® devices are modular multiparameter devices designed to monitor tree physiological parameters (e.g. sap flux, growth) and surrounding microenvironmental parameters (e.g. temperature, humidity). There is a dedicated R package for handling the data produced by this monitoring system: ttprocessing, that has been recently updated, with several improvements in the data processing pipelines, the implementation of the soil water content equations of the TT-soil monitoring device and the inclusion of some basic outlier detection functionalities. In this Technical note, after a summary of the structure of the ttprocessing R package, we describe the new and update version. The updates include: a refinement of the methodology to compute the sap-flux, code for compatibility TT+ devices of version 2.0 and 3.4, that previously were not covered, code for processing the TT-soil data, a device of the Tree Talker system that monitors soil moisture and temperature. Finally, several utility functions have been added: outlier removal and functions for the technical management of the system, thus increasing its usability and making it a more comprehensive tool.

This study used dendroclimatology to examine the effect of climate factors on tree-ring widths of Pinus sylvestris var. mongolica at various altitudes in the northern Greater Khingan Mountains under the background of climate change. Standardized tree-ring width chronologies of Pinus sylvestris var. mongolica were developed at three altitudinal gradients (1150 m, 900 m, 700 m), and relationships between the climate factors and tree-ring width were examined at various time scales. The study found the following: (1) The tree-ring width chronology at high altitudes contained more climate information. (2) Differences were observed in the response of Pinus sylvestris var. mongolica to climate factors at different altitudes. Significant positive (negative) correlations existed between tree-ring width and temperature at high and intermediate (low) elevations. Significant positive (negative) correlations were observed between tree-ring width and precipitation at intermediate and low (high) elevations. (3) Similarities and variations were observed in the trend of the tree-ring width at the three altitudes after an abrupt temperature change. The growth trend increased significantly at high and intermediate altitudes and decreased at low altitudes. The response of high-altitude trees to precipitation weakened, and the response to temperature strengthened. The response of intermediate-altitude trees to temperature increased, and that of low-altitude trees to precipitation weakened. (4) As the temperature increased, the sensitivity of trees to temperature increased (decreased) at high and intermediate (low) altitudes, and the sensitivity to precipitation increased. This study reveals the complex relationships between climate factors and tree-ring width of Pinus sylvestris var. mongolica at different altitudes in the northern Greater Khingan Mountains and provides a scientific basis for evaluating the adaptation capacity of forest ecosystems to future climate change.

Dendrochronology is not a new method for attaining high-precision dates for archaeological and historic remains of timber. But the extent to which dendrochronology is utilized to attain detailed precision of the dating of complex wooden structures can suffer from the fact that the method is often applied in commercial archaeology, where the extent of analysis is severely limited by cost constraints. Instead of lamenting the potentially lost levels of detail that might have slipped through over the years, it is hoped that by presenting the potential of high chronological precision, that necessitates extensive sampling of timber and wood remains on archaeological sites, a new future will be promoted, in which new wide-ranging sampling strategies will become a more normal practice in archaeology, in both the research and commercial spheres. In this paper, I present some case studies where extensive tree-ring analysis of well-preserved wood remains have resulted in annual chronological detail, allowing an insight into the processes of building, and into the duration of structures that comprised the built environment of past peoples’ lives. In addition, we should not discuss precision dating for urban archaeological study without also touching on the subject of timber trade and timber provenance. Tree-ring studies are increasingly providing us with high precision provenance identification, not just for shipwrecks, barrels and other ‘portable’ objects. It is also allowing us to map trade in bulk structural timber. These analyses are providing us with insights into links between territories.

Prof. Dr. Dieter Eckstein (1939 - 2021) significantly influenced the global development of dendrochronology and the underlying science of wood biology. Eckstein’s research areas included dendroclimatology, xylogenesis, ecophysiology, and quantitative wood anatomy. His personal and collaborative work continues to improve our understanding of both the natural environment and human cultural development. The techniques he developed and championed resolved long-standing difficulties in the application of tree-ring science to understand both natural processes and human effects on tree and forest development. As importantly, he nurtured and promoted both the careers and the lives of many fellow scholars and students around the world. Here we present a systematic bibliography of more than 280 publications that illustrates the development of tree-ring research in Europe and elsewhere throughout the almost 50 years of Eckstein’s career. Throughout his scientific career, Eckstein pioneered, developed, and promoted research opportunities with his students and co-workers at the University of Hamburg and beyond. His greatest legacy for his students and colleagues, and which we are challenged to continue, is to continue to build the international spirit of a "dendrofamily".