Dendrochronologia最新文献

In a climate change perspective, the resilience of Mediterranean forest ecosystems is closely linked to their ability to cope with drought and rising temperatures. This ability can be influenced by genetic differences between and within species or provenances. In a changing environment, management guidelines should weight the risks associated both to local and/or non-local provenances, to promote the effective conservation and sustainable management of resilient forest genetic resources. In this study, we analysed the growth responses to drought of silver fir (Abies alba) in the Tuscan-Emilian Apennine National Park in natural and planted forests, comparing the growth performance of three provenances of this species in Italy: (a) Western Alpine - (b) Northern Apennine (local) - (c) Southern Apennine. Drought severity was defined by the Standardised Precipitation-Evapotranspiration Index (SPEI). We carried out dendrochronological analyses by assessing climate-growth relationships and applying drought 'resilience indices' (RRR) based on tree ring width. Planted forests showed faster mean growth than highly fragmented natural forests, higher resilience to severe drought and significantly higher recovery to severe drought. Fir provenances do not differ in mean growth rate, while the Southern Apennine provenance showed significantly better recovery (rec) and resilience (resl) especially compared to the Western Alpine provenance during moderate (rec +5–15%, resl +13–15%) and extreme (rec +20% %, resl +22%) drought years. The local provenance showed an intermediate behaviour. Southern and local provenances showed higher resilience to drought compared to the Western Alpine one, proving to be very important forest genetic resources in the context of climate change response strategies. Finally, the RRR indices trends calculated on the years identified by SPEI6 generally showed greater differences between provenances and regeneration modes than on the years identified by SPEI12, possibly due to the increase in recurrent short-duration droughts in mountainous contexts during the growing season. These results provide important information on the drought response of different silver fir provenances under climate change, highlighting the importance of taking into account the genetic background of forest reproductive materials in forest management and planning. Thanks to the close collaboration with the National Park and local forest managers, these results may find concrete application, e.g., by properly evaluating the usefulness of provenance assisted migration in the National Park forests and providing better management of remnant silver fir natural forests.

In this study the interannual and seasonal dynamics of carbon and oxygen stable isotope composition (δ¹³C, δ¹⁸O), and the resulting intrinsic water use efficiency (iWUE) in xylem rings of Olea europaea L. were investigated. The study was conducted on two high-quality Italian olive cultivars (cv Moraiolo and cv Maurino), grown in central Italy, during the seasons 2020–2022. Variations in both C and O isotope compositions revealed seasonal patterns characterised by the lowest values within the transition from late to early wood rings and the highest values within the transition from early to late wood. The wider seasonal range of δ¹³C, δ¹⁸O and iWUE observed in cv Moraiolo highlighted its ability to adapt to changing environmental conditions. During periods of summer stress, Moraiolo trees close their stomata to reduce transpiration rates, prioritising water conservation to sustain growth. In contrast, Maurino displayed less flexibility in vary its iWUE based on water availability, exhibiting limited responsiveness to environmental fluctuations. The relationship between ecophysiological traits and above-ground development of each caultivar was also discussed.

Late Medieval Limoges (Haute-Vienne department, Central France) represents an example of medium-sized city that relied on timber resources for e.g., construction, heating and crafting. Timber-framed buildings are abundant in the city centre, and although it is generally assumed that the wood used in these structures was sourced locally, historical records lack specific details in this regard. The aim of this study was to gain insight into the organisation of the timber ly for construction purposes in Limoges, a town surrounded by woodlands and connected by rivers to a hinterland of timber sources, using dendrochronological methods. To this end, we sampled 212 oak (Quercus sp.) wooden elements from 13 historic timber-framed houses and used a Hierarchical Cluster Analysis (HCA) approach to identify the origin of wood. Indeed, the HCA can offer insight into the origin of timbers of unknown provenance by grouping them with timbers of known provenance. No clear evidence of timber rafting was observed on the sampled elements. The collected material provided a 419-year-long tree-ring chronology spanning from 1317 to 1735 C.E. Tree-ring analyses revealed that most of the targeted houses date back to the 15th century, and that most of the timber originated from woodlands located in the Haute-Vienne department, within a 50-km radius around the city of Limoges. These results support the assumption that the wood was sourced locally. However, the study does not allow to determine more precisely the origin of individual timbers, highlighting the complexity of wood provenance studies at a local scale in densely forested areas with low environmental variation, such as Central France. We expect future studies combining geochemical tracers with tree-ring analysis to improve the spatial accuracy of the dendroprovenancing analysis presented here.

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.