Dendrochronologia最新文献

Plants growing along altitudinal transects in alpine and mountainous areas respond differently to climatic conditions. The present study is centred on the unique and ecologically significant species, Rhododendron myrtifolium Schott & Kotschy, an evergreen clump-forming or prostrate dwarf shrub. This high-mountain endemic plant grows at several localities in isolated massifs of the Eastern Carpathians, but the greatest numbers of sites can be found in the subalpine and alpine belts of the Chornohora range. The main objectives of this study were (1) to assess the dendrochronological potential of Rhododendron myrtifolium as a new species in dendrochronological research and (2) to compare the growth response of R. myrtifolium (sampling elevation: 1800–1950 m a.s.l.) with Picea abies Karst. (1350–1500 m a.s.l.) and Abies alba Mill. (950–1050 m a.s.l.) collected from the upper and lower forest belts. Tree-ring material from 97 trees and shrubs enabled the construction of three site chronologies from sites located within the altitudinal transect. The longest chronology, covering the previous 184 years, was developed for fir. The chronology for the rhododendron was the shortest at 66 years. This species is the most sensitive of the three species analysed. The highest positive r-value (r=0.71) was obtained between the rhododendron chronology and the warm-season temperature (from March to July). Also, the growth of this species was significantly positively correlated with the summer temperature (r=0.50). In contrast, fir and spruce demonstrated a similar inverse relationship with August temperatures.

Defoliating insects’ outbreaks play a critical role in trees’ carbon cycle. The pine processionary moth (PPM; Thaumetopoea pityocampa) is the major defoliating insect of Mediterranean coniferous forests. The frequency and intensity of PPM outbreaks is projected to increase as winter temperatures become milder due to climate warming. An accurate evaluation of this projection requires a wide spatial baseline of the historical PPM incidence. PPM outbreaks affect tree secondary growth leading to narrow rings, providing a tree level signal. However, PPM defoliation rings can be confounded with drought rings, the most frequent cause of narrow rings in Mediterranean environments. Thus, an accurate identification of PPM rings demands the consideration of additional tree ring traits. Here, we introduce a multiproxy approach to identify and distinguish PPM and drought events. We sampled four Pinus nigra (3) and P. sylvestris (1) stands in Spain. We identified and verified years of PPM defoliation using remote sensing analysis and field observations of Regional Forest Service. We identified drought events through the combination of climatic data with radial growth reductions. We considered climate growth residuals, among-trees growth variability, latewood percentage (%LW), intrinsic water-use efficiency (iWUE) and minimum blue intensity (BI) to discern between droughts and PPM outbreaks. In comparison with drought rings, PPM rings showed 1) more negative residuals in climate growth models, 2) higher secondary growth variance, 3) higher percentage of latewood and 4) lower iWUE. Minimum BI did not differ between drought and PPM rings, but was lower than in the rest of the rings. The combination of these traits provides a signature to identify PPM rings, opening the opportunity to reconstruct PPM incidence on a broad spatio-temporal scale.

Canopy disturbance events in forests often increase light availability and growth rates for surviving trees. Using ring widths, release-detection methods identify the initiation of rapid growth associated with these events enabling reconstructions of forest disturbance history. Conversely, dendroclimate reconstructions minimize these rapid growth responses by detrending entire ring-width time series to resolve underlying climate signals. Incorporating advantages from both of these approaches, we present a canopy disturbance detrending method that quantifies the subsequent, additional growth from release events as a discrete time series. Our method uses radial-growth averaging to detect release events and then power transformation and age-dependent smoothing splines to detrend individual release events, separating canopy disturbance responses from climatic effects. We test our canopy disturbance detrending method on both a coniferous and a broadleaf ring-width chronology from two contrasting temperate forests in eastern North America with known disturbance histories. The resulting disturbance growth time series agrees with the documented forest histories for each forest. Removing the effects of canopy disturbance from the ring-width series in each chronology improves climate correlations with monthly values of temperature and precipitation and may recover more low-frequency variation with past climate compared to other common detrending methods. Our method provides an alternative approach for detrending disturbance events in closed-canopy forests that should be accessible and useful for both ecological and climatological reconstructions.

It was back in the early 1960 s when Bryant Bannister recognized the potential of dendrochronological research on wooden cultural heritage in Greece. More than two decades later, in the late 1980 s, P.I. Kuniholm and C.L. Striker started collecting and analyzing tree-ring series from several historical buildings, forests, and archeological sites in Greece and the surrounding Aegean region. Despite highly promising results, especially from the northern and western parts of the country, dendroarchaeology did not attract much attention in subsequent decades. It was only near the end of the 2000 s that dendroarchaeology was reintroduced: first in Crete through the Cretan Dendrochronology Project, and then by another independent project concerning the restoration of a historical building on the island of Euboea. These isolated case studies inspired a five-year systematic research program called the “Balkan-Aegean Dendrochronology Project: Tree-Ring Research for the Study of Southeast-European and East Mediterranean Civilizations” (BAD project). Dendroarchaeological surveys of historical buildings and archaeological sites were conducted throughout Greece with an emphasis on regions that had been previously ignored, such as the southern part of the country and the Aegean islands. Priority was given to buildings under restoration since in such cases original timbers were usually accessible and the architects, structural engineers, and archaeologists in charge were willing to collaborate. Our goals were not only to date timbers or provide information about the species used or the possible origin of the wood, but also to document the date, evolution, interventions and even the construction phases of historical buildings, as well as to help all those interested parties (academics, non-academics, researchers, professionals, local communities, etc.,) see the value of such information and how dendroarchaeology can contribute to the reconstruction of local history and the protection of cultural heritage. Tree-ring analysis led to the development of 18 chronologies from historical timbers and forests for six different species and different areas of the country from remote mountainous areas to small islands across the Aegean. The current dataset covers more than a thousand (1000) years and demonstrates the further potential of dendroarchaeology in the region.

In the eastern Baltic region, Norway spruce (Picea abies) is predicted to decrease in abundance, resulting in substantial economic consequences. Such predictions have been based on distribution, as well as the sensitivity of growth, largely neglecting the adaptive potential of local populations. Under such circumstances, information on growth sensitivity and its genetic control, as well as productivity-sensitivity relationships is necessary to evaluate the adaptability of populations. Radial increment, which is highly sensitive to local conditions has been mainly used for weather-growth analysis, while height increment, which is a better proxy of productivity due to lower dependence on local density, has been neglected due to laborious gathering of data. Long-term weather sensitivity of annual height increment to weather fluctuations and anomalies (extremes) was estimated by the time series decomposition and multiple regression techniques. Clones of plus-trees from a local population differing by productivity at the age of 55 years growing in an experimental plantation in Latvia were studied. Meteorological conditions prevailingly had carry-over effects on height increment. Thermal regime in winter was the primary driver of height increment with moisture availability in summer showing secondary effects, presuming a positive effect of warming on growth. Abrupt changes in annual increment were related to the co-occurrence of a few weather anomalies, suggesting robustness of height growth. Height increment showed explicit sensitivity-productivity relationships with more productive genotypes being more tolerant and resistant to weather fluctuations. Considering that narrow spatial scale and climatic gradient were analysed, linear and nonlinear responses to weather conditions were estimated implying local adaptation and varying phenotypic plasticity of the genotypes, thus suggesting the persistence of adaptive potential of the local non-marginal population.

Subtropical forests are an important carbon sink, yet our understanding on tree growth response to inter-annual climate variability remains limited. This study investigated the growth-climate relationships of four evergreen broad-leaved tree species (Stewartia pteropetiolata W. C. Cheng, Schima noronhae Reinw. ex Bl. Bijdr, Machilus gamblei King ex J. D. Hooker, and Machilus yunnanensis Lec) in the subtropical evergreen broad-leaved forests (EBFs) in the Ailao Mountains of Yunnan province, southwest China. We constructed tree ring-width residual chronologies for each species and correlated them with daily and monthly climate data. Ring-width chronologies of S. pteropetiolata and S. noronhae were positively correlated with precipitation, relative humidity, and self-calibrated Palmer drought index (scPDSI) during autumn of the previous year and spring-to-early summer of the current year, indicating that these two Theaceae species were sensitive to moisture availability. Tree radial growth of two Machilus species was primarily limited by excessive precipitation and dense cloud cover during the rainy season in this middle montane cloud forest. Moving correlations between climate variables and radial growth of all species were temporally unstable, with a weakening response to climate variability in recent decades. We highlight the dendroclimatic potential of evergreen broad-leaved tree species in moist subtropical forests. The findings offer a pertinent perspective, emphasizing the necessity of separately considering distinct ecological indicators for trees in order to obtain a comprehensive understanding of climate-growth responses within highly diverse subtropical forests.

Drought stress caused by global climate warming affects tree growth in both dry and wet areas. However, the differences in tree growth responses to drought in dry and wet areas are poorly understood. Here, we collected 93 tree cores to analyze the differences in the radial growth responses of larch (Larix gmelinii) under climate change and tree growth resilience under drought events in the Altai Mountains (dry area) and Changbai Mountains (wet area). The results showed that larch growth in the Altai Mountains was significantly positively correlated with the self-calibrating Palmer Drought Severity Index (sc-PDSI) in all months and precipitation in the previous growth season and May, whereas it was significantly (p < 0.05) negatively correlated with temperature in May and the previous June to August. In the Changbai Mountains, larch growth was significantly positively correlated with May maximum and mean temperature, and significantly positively and negatively correlated with precipitation in April and May，respectively (p < 0.05). The mean resistance (recovery) of larch growth to drought in wet areas were significantly stronger (weaker) than that in dry areas (p < 0.05). Moreover, strengthening the drought frequency led to a significant (p < 0.05) decline in larch resistance in dry areas. Therefore, warming-induced increases in drought stress will aggravate negative impacts on the radial growth of larch forests in temperate dry areas but not in wet areas in the future.

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.