ALBERT

Description: Publication date: Available online 11 January 2014 Source: Dendrochronologia Author(s): Andrea Klein , Sebastian Nemestothy , Julia Kadnar , Michael Grabner In the present study, 208 furniture and 168 coopered vessels from three Austrian museums were examined. Dendrochronology was used to date objects and to extract further information such as the necessary time for seasoning, wood loss through wood-working and methods of construction. In most cases sampling was done by sanding the cross section and making digital photographs using a picture frame and measuring digitally. The dendrochronological dates of the sampled furniture range between 1524 and 1937. The group of furniture includes cupboards, chests, tables, benches, commodes and beds. In many cases furniture was artfully painted and sometimes even shows a painted year. With the help of dendrochronology it was proved that some objects had been painted for some time after construction, or had been over-painted. Most furniture, however, was painted immediately after completion. In this case the seasoning and storage time of the boards and the wood loss due to shaping can be verified. As an average value, 14 years have passed between the dendrochronological date of the outermost ring and the painting. The time span includes time of seasoning and storage and the rings lost by wood-working. This leads, on the one hand to a short storage time of less than ten years and on the other hand to very little wood loss due to manufacturing. Those boards being less shaped turned out to be back panels of cupboards, therefore they are recommended to be sampled for dating. Coopered vessels were dated between 1612 - 1940. There was evidence that staves were split and not sawn in many cases. The staves were often split out of the outermost part of the tree and hardly any wood was worked away which was proved by the close dendrochronological dates of the single staves of a vessel. Since there is a short time of storage and only little wood loss through wood-working, dating of objects without a waney edge becomes reasonable.

Description: Publication date: Available online 21 March 2014 Source: Dendrochronologia Author(s): Melissa Dick , Trevor J. Porter , Michael F.J. Pisaric , Ève Wertheimer , Peter deMontigny , Joelle T. Perreault , Kerry-Lynn Robillard The early settlement history of Canada's National Capital Region, including Ottawa (Ontario) and Gatineau (Québec), was shaped in large part by the towering eastern white pine ( Pinus strobus ) forests that once covered the Ottawa Valley and fuelled a lucrative lumber export industry spanning the 19 th and much of the 20 th century. Some of the first dwellings and farmsteads of this era are still standing and serve as reminders of this history. A crucial piece of information in the assessment of a structure's heritage value is its date of construction. Unfortunately, this information is not always known and is approximated based on construction styles and other sources of information. In this study, dendroarchaeology methods are applied to constrain the construction dates of six historic structures in the National Capital Region of 19 th century vintage. A multi-century (AD 1670-2009) eastern white pine ring-width chronology was developed for dating the study structures using cross sections from sunken logs recovered from the Ottawa River and cores from live trees from the Petawawa Research Forest. The tree-ring inferred construction dates for the six structures ranged from 1830 to 1878. For most structures, historical records about the property or first inhabitants were available to corroborate the results. The ring-width chronologies of the individual structures were well correlated with the regional chronology (r avg = 0.63, p ≤ 0.01), and this regional coherence clearly demonstrates the value of tree-rings for heritage structure assessments and reconstructing the settlement history of this region.

Description: Publication date: Available online 29 March 2014 Source: Dendrochronologia Author(s): Mark D. Spond , Saskia van de Gevel , Henri D. Grissino-Mayer We sampled Rocky Mountain junipers (RMJ) to produce a multi-century tree-ring chronology from a relict lava flow, the Paxton Springs Malpais (PAX), in the Zuni Mountains of western New Mexico. Our objective was to assess crossdating potential for RMJ growing on the volcanic badlands of the region, investigate potential relationships between climate and RMJ growth, and investigate temporal variability in relationships identified between climate and RMJ growing at our site. We hypothesized that, similar to other drought stressed-conifers growing on the lava flows, RMJ responds to climate factors that influence and indicate moisture availability. We found a high average mean sensitivity value (0.53), which indicated the PAX chronology exhibited enough annual variability to capture fluctuations in environmental conditions. The average interseries correlation (0.74) indicated confident crossdating and a significant association of annual growth among trees within the stand. The positive correlation between the PAX chronology and total precipitation for the local water year was significant (r = 0.53; P 〈 0.001). Significant positive correlations also were identified between monthly PDSI, monthly total precipitation, and RMJ radial growth. Analyses of temporal stability indicated that the positive relationship between RMJ growth at the PAX site and monthly PDSI was the most stable relationship during the period of analysis (1895–2007). More importantly, we identified a unique inverse relationship between radial growth and monthly mean temperature during periods of the preceding year and current growing year, the first such finding of a strong temperature response for a low-mid elevation tree species in the American Southwest. Our results confirm that RMJ samples collected on the Paxton Springs Malpais are sensitive to climate factors that affect moisture availability, further suggesting that RMJ may be suitable for use in dendroclimatic research at additional locations across the broad distribution of the species.

Description: Publication date: Available online 30 March 2014 Source: Dendrochronologia Author(s): Tongwen Zhang , Yujiang Yuan , Qing He , Wenshou Wei , Mamatkanov Diushen , Huaming Shang , Ruibo Zhang Three tree-ring width chronologies were developed from 75 Picea schrenkiana trees ranging from low- to high-elevation in the mountains surrounding the Issyk-Kul Lake, Northeast Kyrgyzstan. The reliable chronologies extend back to the mid-18th and late-19th centuries. Spatial correlation analysis indicates that the chronologies for the relatively high-elevation trees contain large-scale climatic signals, while the chronology at relatively low elevation may reflect the local climate variability. The results of the response of tree growth to climate show that these chronologies contain an annual precipitation signal. Furthermore, the influence of temperature indicates mainly moisture stress that is enhanced with rising elevation. The tree-ring records also captured a wetting trend in eastern Central Asia over the past decades. These new tree-ring width chronologies provide reliable proxies of precipitation variability in Central Asia and contribute to the International Tree-Ring Data Bank.

Description: Publication date: Available online 2 October 2014 Source: Dendrochronologia Author(s): Katarina Čufar , Matjaž Bizjak , Manja Kitek Kuzman , Maks Merela , Michael Grabner , Robert Brus Castle Pišece, located in SE Slovenia near the border with Croatia, is thought to have been built in the 12 th /13 th century as one in the line of Salzburg fortresses on the then SE border of the Holy Roman Empire. During thorough restoration that started in 2005, its wooden constructions became accessible for dendrochronological investigations. We collected representative samples from floor or ceiling constructions in most of the rooms in the castle. Dendrochronology helped us to identify felling dates of wood and to propose probable years of reconstructions in 1515, 1578, 1644, 1697, 1752, 1758, 1775 and 1878. The dating showed that the constructions in the presumed Romanesque and Renaissance parts of the building were not as old as expected, whereas those in the supposedly Baroque part of the castle were older than assumed. The selection of wood species used for constructions varied over time. Constructions with end dates 1515-1697 were made of oak ( Quercus petraea and Q. robur ), those dated to 1752 of silver fir ( Abies alba ), those dated to 1758 of sweet chestnut ( Castanea sativa ) and those dated to 1878 of common beech ( Fagus sylvatica ). Comparison of forestry archives and vegetation in the area showed that most of the timber could have originated from nearby forests; only silver fir had to be transported from sites that were at least 20 km away from the castle. Cross-dating of tree-ring series of oak elements with two reference chronologies from Slovenia and two from Austria confirmed the great likelihood that the wood used mostly originated from Slovenia. This indicates that dendroprovenancing, not used in the area before, could also be used SE of the Alps. Both the existing archival documents and dendrochronology indicate that woodworks have taken place every few decades in some periods. The dendrochronological dates can be partly linked to reports on earthquakes (especially the devastating one in 1511), rebellions and year marks carved on the stone plaques. Graphical abstract

Description: Publication date: Available online 1 September 2014 Source: Dendrochronologia Author(s): Martin Hroš , Hanuš Vavrčík The differences in the microscopic structure of wood based on the variables of earlywood vessel area and tree ring width were analysed in 6 trees of Pedunculate oak (Quercus robur L.) and 6 trees of Sessile oak (Quercus petraea (Mattuschka) Liebl.) in the same forest stand at a site in the Vizovice Highland (Czech Republic). The aim of this paper was to assess any differences between the two oak species when grown in the same location. Also the effect of tree-ring width and the effect of age on earlywood vessel variables were analysed. Mean values of tree-ring widths were not different between species. Earlywood vessel area chronologies were synchronised well between species. The mean values of earlywood vessel area (average vessel area, average vessel area of the first row of vessels, area of the largest vessel) showed a significant difference. Finally, we can conclude that there were differences in vessel features between these oak species.

Description: Publication date: Available online 21 November 2014 Source: Dendrochronologia Author(s): Pearce Paul Creasman , Christopher Baisan , Christopher Guiterman More than 200 ships were built, and thousands serviced, at Charlestown Navy Yard (Boston, MA) in its 174 years of service for the U.S. Navy (1800–1974 C.E.). Recent redevelopment of portions of the former yard revealed an historic timber pond where hundreds of unfinished naval-quality ship timbers were intentionally sunk and remained buried until ca. 2008. Many of these timbers were offered to the Henry B. du Pont Preservation Shipyard (Mystic Seaport, CT) for their restoration of Charles W. Morgan . Courtesy of Mystic Seaport, thirty-eight specimens from the Charlestown yard (mostly Quercus sp.; including live [evergreen] oak and white oak) were selected for dendrochronological analysis. Most of the white oak specimens could be sourced with confidence to Ohio. Dates clustered in the late 1860's, suggesting late-Civil War or Reconstruction Era activities. This paper discusses the dates, origin, and other findings derived from this collection.

Description: Publication date: Available online 11 November 2014 Source: Dendrochronologia Author(s): Rui-bo Zhang , Yu-jiang Yuan , Wen-shou Wei , Xiao-hua Gou , Shu-long Yu , Hua-ming Shang , Feng Chen , Tong-wen Zhang , Li Qin We developed three tree-ring width chronologies of Dragon Spruce ( Picea likiangensis var. balfouriana) from Qamdo region in the eastern Tibetan Plateau. It was found that the autumn-winter mean minimum temperature was the principal factor that limited the radial growth of Dragon Spruce. In particular, the tree-ring width chronology of the Changdu site was related significantly and positively with the autumn-winter mean minimum temperature. Using standard dendrochronological (STD) method, we obtained a 400-year reconstruction of October–January minimum temperature at the Qamdo meteorological station. The reconstruction explains 43.1% of the variance in the instrumental temperature records during the 1954–2006 calibration periods. It indicates that quasi-periodic changes exist on scales of 5, 11, and 102–103a. The temperature fluctuates around the mean and rises slowly from 1594 to the 1700s, following which the autumn-winter mean minimum temperature exhibited obvious stage changes with warmer periods (1769–1800, 1819–1849, 1873–1900, 1926–1954, 1987–2006) and colder periods (1716–1768, 1801–1818, 1850–1872, 1901–1925, 1955–1986). The temperature in the eastern Tibetan Plateau and the mean temperature in the Northern Hemisphere exhibited good consistency in the 20th century. From 1900 to the 1930s, the temperature rose slowly and then declined sharply in the 1940s. In the 1950s, the temperature rose, before falling again in the early 1960s, prior to a gradual increase following the late 1960s. The temperature in Qamdo represents the temperature of the southeastern Tibetan Plateau, and significant positive correlations were found with other temperature reconstructions on the southeastern Tibetan Plateau and the southern slopes of the Himalaya (including the Indian peninsula). The India-Burma Trough may have a certain effect on climate change in the eastern Tibetan Plateau. The reconstruction sheds new light on temperature variability and change in a region where the climate history for the past several centuries is poorly understood.

Description: Publication date: Available online 24 November 2014 Source: Dendrochronologia Author(s): Xu Deng , Qi-Bin Zhang The creation of forest openings is a frequently observed phenomenon in many types of forests. On the southeastern Tibetan Plateau, where the average elevation is greater than 4000 m above sea level, differences in tree growth between forest stands with openings and completely closed stands are poorly characterized. Here, we presented a dendrochronological study of Tibetan juniper ( Juniperus tibetica Kom.) and Sikkim spruce ( Picea spinulosa (Griff.) Beissn . ) in an open and a closed stand, near Qamdo of eastern Tibet. We found that the growth of juniper responded to climate in a similar way in the open and closed stands, and was positively correlated with temperature from October to January and with the Palmer Drought Severity Index (PDSI) from September to June. In contrast, the growth of spruce responded to climate differently in the open and closed stands: growth was positively correlated with the PDSI from September to May in the open stand, whereas it was positively correlated to November and December temperatures (of the prior year) and current June temperature in the closed stand. Interannual variation in, and standard deviations among, juniper tree ring widths were similar in both stands for the past four centuries, whereas they differed in spruce over the past two centuries, particularly in the 1900s. These results suggest that juniper tree ring growth is less sensitive to stand structure than that of spruce, thus providing more reliable climate signals. The data obtained from our study will help forest managers understand the ecology of juniper and spruce in open and closed stands and are therefore useful for management planning.

Description: Publication date: Available online 24 November 2014 Source: Dendrochronologia Author(s): Facundo José Oddi , Luciana Ghermandi Fire recurrently affects Mediterranean-type climate (MTC) regions causing major implications on the structure and dynamics of vegetation. In these regions, it is important to know the fire regime for which reliable fire records are needed. Dendroecology offers the possibility of obtaining fire occurrence data from woody species and has been widely used in forest ecosystems for fire research. Grasslands are regions with no trees where shrubs can provide dendroecological evidence for reconstructing fire history at landscape scale. We studied the dendroecological potential of the shrub F. imbricata to reconstruct fire history at landscape scale in MTC grasslands of northwestern Patagonia. In order to accomplish this, we combined spatio-temporal information of recorded fires from the study area with the age structure of F. imbricata shrublands obtained from dendroecological methods. Shrubland age structure correctly described how often fires occurred in the past. In rocky outcrops, where fires cannot reach, individuals are long-lived and heterogeneous in age; while downhill, individuals are young and shrublands are even-aged. Five pulses of massive recruitment were found: three of these coincided with three known fires; the remaining two had not been recorded before. A bi-variated analysis showed that F. imbricata recruited mainly during two years after fire, and the spatial distribution of pulses coincided with the fire map. Information derived from shrubland age structure could be used to estimate fire regime parameters such as fire return interval at landscape or community scale. For instance, we estimated a fire return interval of nine years at landscape scale and ranging from 11-24 years at community scale (shrubland). Our results in northwestern Patagonia grasslands showed that the F. imbricata chronology can be used to complement other information sources such as remote sensing and operational databases improving the knowledge about fire regime. The present study demonstrates that is possible to utilize shrubs as a dendroecological data source to study fire history in regions where tree cover is absent.

Description: Publication date: Available online 6 September 2014 Source: Dendrochronologia Author(s): Kristen K. de Graauw , Ronald H. Towner , Henri D. Grissino-Mayer , Nicholas V. Kessler , Jonathan Knighton-Wisor , Anastasia Steffen , James P. Doerner We used dendroarchaeological techniques to determine the year of construction of two historic structures in the Valles Caldera National Preserve of New Mexico, USA. Historical documents date some structures in the headquarters area of the preserve, but the Commissary Cabin and Salt Barn were lacking conclusive construction dates. Both structures were originally thought to have been built by the Otero family who bought the property in 1899. We found that the structures were built from two tree species, white fir ( Abies concolor (Gordon) Lindl. ex Hildebr.) and Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco), surprising given that ponderosa pines are also found in great numbers in the adjacent forest. Tree rings from 20 logs were confidently crossdated both graphically and statistically and provided cutting dates of trees in both structures of 1940 and 1941 when compared against the Fenton Lake reference chronology (Commissary Cabin: r = 0.69, t = 15.54, p 〈 0.0001, n = 263 years; Salt Barn: r = 0.77, t = 11.7, p 〈 0.0001, n = 232 years). By combining the cutting date years and terminal ring attributes, we suggest that both structures were built in the spring or early summer of 1941 using freshly cut logs and logs that had been cut the previous spring (1940, before or during the growing season) and stockpiled. The cutting dates of 1940 and 1941 indicate that these buildings were constructed during the Franklin Bond (1939-1945) era and associated with the transition from sheep ranching to more modern cattle grazing. These new dates provide a more distinct understanding of the cultural resources at the Valles Caldera National Preserve and provide interpretative staff with more accurate information that can be given to the public.

Description: Publication date: Available online 6 December 2014 Source: Dendrochronologia Author(s): Christian Zang The International Tree-Ring Data Bank (ITRDB) is the main public archive of digital tree-ring parameters. Due to its comprehensive spatio-temporal coverage, its ring-width data is acknowledged in many studies where high-resolution proxies of climate or tree-growth are needed on large scales. A main drawback of existing approaches to browsing the ITRDB is the lack of an easy and interactive visualization of the records and their connection to the climate at point. Dendrobox aims at filling this gap, and provides a web-based interface to more than 2400 ring-width records in the ITRDB for exploring chronology characteristics and the dendroclimatological potential of the records. Possible applications of Dendrobox include identifying records with a specific climate response, demonstrating the relations of tree-growth and climate in teaching, or simply playing with an impressive data set without the hassle of setting up analytical tools.

Description: Publication date: Available online 5 December 2014 Source: Dendrochronologia Author(s): Elizabeth A. Schneider , Lauren A. Stachowiak , Henri D. Grissino-Mayer Tree rings of eastern red cedar ( Juniperus virginiana L.) were examined from cores extracted from two log cabins located at the Wynnewood State Historic Site in Castalian Springs, Sumner County, Tennessee. One cabin was reportedly built by the first explorer in the area, Isaac Bledsoe, sometime between 1772 and his death in 1793. The second cabin was known as Spencer's Cabin after the first settler of the region, Thomas Sharp Spencer, who lived in the immediate vicinity from 1776 to 1779. The goal of this research was to determine the probable construction year(s) for both cabins and determine whether Bledsoe and Spencer did indeed build these structures. Forty-one cores were extracted from Bledsoe's Cabin, and 30 were used for crossdating and building a floating chronology using COFECHA. The Bledsoe's Cabin chronology was then statistically and graphically crossdated using the eastern red cedar reference tree-ring chronology (ITRDB #TN031) from Norris Dam, Tennessee. We found a statistically significant correlation (r = 0.42, t = 4.18, n = 85, p 〈 0.0001) between the Bledsoe's Cabin chronology and the reference chronology, anchoring the chronology between 1720 and 1804, with nearly all cores indicating tree harvesting between February and April 1805. Twenty-two cores were extracted from Spencer's Cabin, and 17 were used to build a floating chronology for the cabin. Again, we found a statistically significant correlation (r = 0.44, t = 4.85, n = 100, p 〈 0.00001) with the reference chronology which anchored the Spencer's Cabin chronology between 1726 and 1825. All trees appear to have been harvested between February and August in 1826. Therefore, neither structure was built by its historical namesake. No known historical documents suggest who the potential builders were, although the property was owned between ca. 1797 and 1826 by General James Winchester. He and his family, however, never resided on the Wynnewood property because Winchester had built a large multi-room structure in nearby Gallatin, Tennessee by 1802.

Description: Publication date: Available online 28 February 2014 Source: Dendrochronologia Author(s): Santosh K. Shah , Amalava Bhattacharyya , Vandana Chaudhary The relationship of streamflow records of the Lachen River with tree-ring parameters of total tree-ring width (TRW), earlywood width (EWW) and latewood width (LWW) chronologies of Larix griffithiana from Lachen, North Sikkim, Eastern Himalaya was generated. These chronologies correlate significantly with the observed discharge of the Lachen River where the EWW chronology explains 61.2% of the streamflow variance. Based on this result, Lachen River discharge for the period of previous year March to current year February was reconstructed using EWW chronology, which extends back to AD 1790. In the smoothed reconstructed data the period of extreme low streamflows were during AD 1791-1805, 1813-1822 and 1914-1925 and the extreme highs were during AD 1823-1835, 1879-1890, 1926-1946 and 1980-1989. The streamflow is also found to be lower than average during the monsoon failure (or East India Drought) of AD 1792-1796 and past great droughts of AD 1876-1878. The lower tree growth during AD 1816-1822 is consistent with that of the Tambora volcanic eruption of Indonesia in AD 1815. High spectral power at 4-8 years in the reconstructed streamflow is similar to that of ENSO range.

Description: Publication date: Available online 28 February 2014 Source: Dendrochronologia Author(s): J. Altman , P. Fibich , J. Dolezal , T. Aakala Studies using tree-rings to reconstruct forest disturbance dynamics are common and their number has been increasing in the recent years. Despite the evident need for a common set of tools for verification, replication and comparison across studies, only a few DOS programmes for disturbance detection exist and they are for limited purposes only. Currently, the ideal statistical environment for the task is R, which is becoming the primary tool for various types of tree-ring analyses. This has led to the development of TRADER (Tree Ring Analysis of Disturbance Events in R), an open-source software package for R that provides an analysis of tree growth history for disturbance reconstructions. We have implemented four methods, which are commonly used for the detection of disturbance events: radial-growth averaging criteria developed by Nowacki and Abrams (1997), the boundary-line method (Black and Abrams, 2003), the absolute-increase method (Fraver and White, 2005), and the combination of radial-growth averaging and boundary-line techniques (Splechtna et al., 2005). TRADER, however, enables the analysis of disturbance history by a total of 24 published methods. Furthermore, functions for the detection of tree recruitment and growth trends were also included. The main features of the presented package are described and their application is shown on a real tree-ring datasets. The package requires little knowledge of the R environment giving straightforward analyses with suitable parameters, but at the same time it is easily modifiable by the more experienced user. The package improves research efficiency and facilitates replication of previous studies. One of its major advantages is that it offers the possibility for comparison between different methods of disturbance history reconstruction.

Description: Publication date: Available online 28 February 2014 Source: Dendrochronologia Author(s): María Eugenia Ferrero , Ricardo Villalba , Stella Maris Rivera Most subtropical forests in South America are located in regions with a marked seasonality in precipitation, which may induce the formation of annual bands in woody species. Due to the lack of precise information on tree-ring visibility, we evaluated the wood characteristics of 37 tree species in the subtropical Yungas and Chaco forests from northwestern (NW) Argentina. Anatomical features associated with the delimitation of growth bands were examined to establish the presence of tree rings. Different forest types reflect the precipitation gradients and wood anatomical features vary accordingly. Characteristics of wood structure are closely related to the dominant climatic patterns of each forest, revealing a common pattern of anatomical arrangements in terms of water transport and safety. In the Chaco and transitional forests, ring boundaries are related to marginal parenchyma whereas in montane forests growth ring boundary is mostly associated with the presence of ticker fibers at the end of the ring. The largest proportion of species with clearly marked growth rings occurs in the montane forest type of NW Argentina. Clear growth rings is a requisite for dendrochronological applications, hence the present work represents the first regional attempt to address the potential of subtropical species in South America to be used in dendrochronological studies.

Description: Publication date: Available online 18 April 2014 Source: Dendrochronologia Author(s): Angelo Rita , Tiziana Gentilesca , Francesco Ripullone , Luigi Todaro , Marco Borghetti Pointer year analysis, simple correlations, and response functions were combined in a dendroecological study to evaluate climate-growth relationships over the last century in two Abies alba Mill. and Fagus sylvatica L. mixed stands in Southern Italy mountainous areas. Analyses revealed species-specific attributes at the two study sites, i.e. Molise and Basilicata. Growth divergence between the two species emerged based on three primary climatic drivers, including drought stress and spring warmer temperatures during the current growing season for F. sylvatica, and water availability in the previous growing season for A. alba. However, despite the microclimatic differences between the two study sites, F. sylvatica showed similar climate-growth patterns, while differences were indicated for A. alba, due to its minor susceptibility to drought stress during the current growing season at the Basilicata site. Indeed, at the southernmost geographic limits of A. alba drought avoidance mechanisms were confirmed, consistent with traits considered diagnostic for the species in the Mediterranean region.

Description: Publication date: Available online 13 April 2014 Source: Dendrochronologia Author(s): Kathleen C. Parker , Carrie Jensen , Albert J. Parker We examined tree-ring growth in a naturally seeded old-growth slash pine ( Pinus elliottii Engelm. var. elliottii ) stand in coastal Georgia to develop growth-climate models and reconstruct past climatic conditions during the mid and late 1800s. We generated earlywood, latewood, and annual ring chronologies dating to 1818, based on 40 cores collected from 22 trees at the Wormsloe State Historic Site near Savannah, Georgia, with 28 cores dating before 1900. We used correlation and response function analysis to relate tree-ring growth to climatic variables and El Niño/Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) indices. Water availability (represented by PDSI and secondarily, precipitation) was the most important factor determining growth for all three series, with latewood and September PDSI showing the strongest relationship. Like other species in the southeastern United States, moisture in the late winter and spring was crucial for earlywood development, while latewood and annual growth was enhanced in cooler, wetter summers, particularly with hurricanes bringing rainfall late in the growing season. Earlywood growth was greater following +ENSO (winter) phases and–NAO (winter) phases—for both indices, times when the northern Georgia coast is often relatively cool and wet. A verified split-calibration regression model based on latewood ring growth showed temporal stability and accounted for 27% of the variation in the observed September PDSI record from 1895-2009 (mean reduction in error = 0.21 and coefficient of efficiency = 0.05). During the instrument record, the timing of reconstructed and observed dry and moist periods matched closely; prior to that, reconstructed PDSI values indicated drought from the early 1840s-late 1850s—a period of unusually low latewood growth.

Description: Publication date: Available online 18 April 2014 Source: Dendrochronologia Author(s): Stephen Galvin , Aaron Potito , Kieran Hickey Tree-ring research in Ireland has typically been dominated by Quercus species, particularly Q. petraea and Q. robur . Recent years have seen a greater focus on multi-species reconstructions in Ireland but, due to difficulties with the hardness of the wood, missing/pinched rings and fused stems, Taxus baccata has not been included in these investigations. Despite these difficulties, a 31-tree, 204-year T. baccata chronology was successfully constructed from Killarney National Park, southwest Ireland. The chronology exhibits promisingdendroclimatologicalpotential, with climatic responsiveness equivalentto that of the other major Irish tree taxa, including Quercus . The chronology shows the strongest relationship with May-June precipitation from Muckross House synoptic station (1970-2007; r =0.521, p 〈 0.01) and Valentia Observatory (1941-2007; r = 0.545, p 〈 0.01). November-April temperatures also exhibited a strong relationship with the chronology post-1970 (r = 0.605, p 〈 0.01 for Muckross House, r = 0.567, p 〈 0.01 for Valentia Observatory), but this relationship is not time stable and breaks down for the pre-1970 Valentia Observatory record. The long-lived nature of T. baccata , the exceptional preservation of wood and rings in this hard softwood species, as well as its prominence in Irish archaeology, all point to the potential to expand this chronology both spatially and temporally, and demonstrate T. baccata 's potential in multi-site and multi-species tree-ring studies in the region.

Description: Publication date: Available online 20 December 2014 Source: Dendrochronologia Author(s): Marzena Kłusek , Thomas M. Melvin , Michael Grabner This paper presents a multi-century, maximum latewood density (MXD) chronology developed from living and sub-fossil spruce trees from the Eastern Alps. The chronology is continuous from 88AD to 2008AD. This time series has been analysed with respect to its possible use for climate reconstruction. Correlations with climatic data showed strong dependence between MXD of growth rings and temperature of April, May, June, July, August and September and a weaker, negative dependence with precipitation of May and September. For solar radiation a positive relationship was noted for April, July, August and September. Light rings were frequently observed within the analysed samples and the climate of years with light rings was examined. Mean monthly temperatures in January, June, August, September and October, averaged during light ring years, were cooler than during years without light rings. Precipitation was also significantly reduced in March during light ring years. In turn, solar radiation during light ring years has significantly lowered values in February and August. The occurrence of light rings was often positively related to strong volcanic events.

Description: Publication date: Available online 12 August 2014 Source: Dendrochronologia Author(s): Róbert Sedmák , Denisa Sedmáková , Michal Bošeľa , Róbert Marušák , Marek Ježík , Vlastimil Murgaš , Miroslav Blaženec Information on tree age is often vital for dendrochronological studies, especially when the Regional Curve Standardisation technique is used. Several linear and non-linear methods of tree age estimation using partial increment cores (without the presence of pith) were evaluated and modified to provide more accurate estimations than are currently used. To achieve the objective, core samples from 142 Norway spruce trees ( Picea abies [L.] Karst.) were collected from an altitudinal gradient in the Western Carpathians. The samples in which the pith was included were then used for further analyses. Several known age estimation approaches were adjusted to combine the advantages of direct increment- and indirect age-diameter-based methods. Inverse differential forms of non-linear growth functions were tested and proposed as a new advanced approach for age estimation. The results show that most of the modified linear methods achieved a mean square error of less than 10% when the length of the partial core exceeded 90% of the stem radius and less than 20% when the length of the core was at least 60% of the stem radius. Using an appropriate differential form of the non-linear growth functions, a mean square error of less than 20% was reached, even when the core length was shorter than 60% of the radius. The results show that current linear methods for age estimation can only be used if the missing part of the core sample is very short, with only a few rings absent. In the case of a large number of missing rings, a differential form of non-linear functions should preferably be used instead

Description: Publication date: Available online 15 August 2014 Source: Dendrochronologia Author(s): Emanuele Ziaco , Franco Biondi , Sergio Rossi , Annie Deslauriers Mountain conifers in the Great Basin of North America have provided some of the longest, continuous, and annually-resolved paleoclimate records. Climate-growth relationships at the cellular level, which help understand wood formation processes that underlie dendroclimatic reconstructions, are at present largely unexplored in the Great Basin. We analyzed 42 trees located in the Snake Range (eastern Nevada, USA) at three sites along an elevation gradient. Sampled species included white fir ( Abies concolor ), Douglas fir ( Pseudotsuga menziesii ), limber pine ( Pinus flexilis ), bristlecone pine ( Pinus longaeva ), and Engelmann spruce ( Picea engelmannii ). Wood anatomical features were quantified for two consecutive years, 2011 and 2012. Lumen area, cell wall thickness, lumen diameter, and wall-to-cell ratio were measured for the total ring as well as for earlywood and latewood. Mean standardized tracheidograms highlighted differences between 2011 and 2012, in particular concerning lumen area and wall-to-cell ratio. Most annual variation was due to earlywood, rather than latewood. Anatomical parameters of limber pine, the only species that could be tested at both the montane and subalpine sites, varied with elevation. Principal component analysis showed that the main axis of variability was related to dimensional parameters (e.g. lumen area), which reflected differences in water availability.

Description: Publication date: Available online 28 August 2014 Source: Dendrochronologia Author(s): Thomas M. Melvin , Keith R. Briffa A number of processing options associated with the use of a “regional curve” to standardise tree-ring measurements and generate a chronology representing changing tree growth over time are discussed. It is shown that failing to use pith offset estimates can generate a small but systematic chronology error. Where chronologies contain long-timescale signal variance, tree indices created by division of the raw measurements by RCS curve values produce chronologies with a skewed distribution. A simple empirical method of converting tree-indices to have a normal distribution is proposed. The Expressed Population Signal, which is widely used to estimate the statistical confidence of chronologies created using curve-fitting methods of standardisation, is not suitable for use with RCS generated chronologies. An alternative implementation, which takes account of the uncertainty associated with long-timescale as well as short-timescale chronology variance, is proposed. The need to assess the homogeneity of differently-sourced sets of measurement data and their suitability for amalgamation into a single data set for RCS standardisation is discussed. The possible use of multiple growth-rate based RCS curves is considered where a potential gain in chronology confidence must be balanced against the potential loss of long-timescale variance. An approach to the use of the “signal-free” method for generating artificial measurement series with the ‘noise’ characteristics of real data series but with a known chronology signal applied for testing standardisation performance is also described.

Description: Publication date: Available online 2 August 2014 Source: Dendrochronologia Author(s): Giovanna Battipaglia , Veronica De Micco , Ute Sass-Klaassen , Paolo Charubini

Description: Publication date: Available online 18 June 2014 Source: Dendrochronologia Author(s): Edmond Pasho , Elvin Toromani , Arben Q. Alla The long-term radial growth responses to drought and climatic variability of less-studied species such as Abies borisii-regis (Mattf.) remain poorly understood. We tested the hypothesis that severe short-term drought conditions during summer months will impact the radial growth of Abies borisii-regis (Mattf.) trees and such impact will have a more pronounced effect on latewood (LW) than earlywood (EW) width. Correlation analysis was employed to investigate the impact of climatic drivers (temperature, precipitation) and drought, using the Standardized Precipitation Evapotranspiration Index (SPEI) calculated at cumulative time scales (1–12 months), on EW, LW and tree-ring width (TRW) in A. borisii-regis (Mattf.) trees from South-Eastern Albania. We found that EW width was positively correlated with precipitation in July and previous September, while the LW width and TRW was enhanced by the current June-July precipitation. Previous autumn and current summer high temperatures constrained the radial growth in A. borisii-regis (Mattf.) trees, particularly the LW and TRW. All the tree-ring widths components showed the highest significant response to drought at short cumulative time scales (〈 4 months) mainly during July, August and September. The highest impact of drought was observed for the LW width. Under a future reduction of summer precipitation and temperature increase, the A. borisii-regis (Mattf.) may show a decrease in EW formation, causing a decline of radial growth, leading to a reduction in hydraulic conductivity and carbon uptake in these forests.

Description: Publication date: Available online 17 May 2014 Source: Dendrochronologia Author(s): Miloš Rydval , Lars-Åke Larsson , Laura Mcglynn , Björn Gunnarson , Neil J. Loader , Giles H.F. Young , Rob Wilson Blue Intensity (BI) has the potential to provide information on past summer temperatures of a similar quality to maximum latewood density (MXD), but at a substantially reduced cost. This paper provides a methodological guide to the generation of BI data using a new and affordable BI measurement system; CooRecorder. Focussing on four sites in the Scottish Highlands from a wider network of 42 sites developed for the Scottish Pine Project, BI and MXD data from Scots pine ( Pinus sylvestris L.) were used to facilitate a direct comparison between these parameters. A series of experiments aimed at identifying and addressing the limitations of BI suggest that while some potential limitations exist, these can be minimised by adhering to appropriate BI generation protocols. The comparison of BI data produced using different resin-extraction methods (acetone vs. ethanol) and measurement systems (CooRecorder vs. WinDendro) indicates that comparable results can be achieved. Using samples from the same trees, a comparison of both BI and MXD with instrumental climate data revealed that overall, BI performs as well as, if not better than, MXD in reconstructing past summer temperatures (BI r 2 = 0.38 - 0.46; MXD r 2 = 0.34 - 0.35). Although reconstructions developed using BI and MXD data appeared equally robust, BI chronologies were more sensitive to the choice of detrending method due to differences in the relative trends of non-detrended raw BI and MXD data. This observation suggests that the heartwood-sapwood colour difference is not entirely removed using either acetone or ethanol chemical treatment, which may ultimately pose a potential limitation for extracting centennial and longer timescale information when using BI data from tree species that exhibit a distinct heartwood-sapwood colour difference. Additional research is required in order to develop new methods to overcome this potential limitation. However, the ease with which BI data can be produced should help justify and recognise the role of this parameter as a potential alternative to MXD, particularly when MXD generation may be impractical or unfeasible for financial or other reasons.

Description: Publication date: Available online 22 May 2014 Source: Dendrochronologia Author(s): Jeong-Wook Seo , Marko Smiljanić , Martin Wilmking Cell-anatomical studies are a fast growing branch of dendrochronology, since they promise additional environmental proxy information with high temporal resolution. It is unclear, however, how many radial files of tracheids have to be considered to establish reliable wood anatomical time series for conifer species. Here, we investigate this question for four common cell-anatomical variables (cell-wall thickness, lumen area, lumen diameter and cell diameter) in Scots Pine using examples from three Scandinavian sites. Cell-anatomical time series averaged from six measurement paths can reach the 90% confidence level of ten measurement paths at all sites. While lumen area generally required the most measurement paths in other cell-anatomical variables, cell-wall thickness required the least measurement paths.

Description: Publication date: Available online 22 May 2014 Source: Dendrochronologia Author(s): Gianluigi Mazza , Valeria Gallucci , Maria Chiara Manetti , Carlo Urbinati This study is part of a LIFE+ project on marginal mountain ecosystem conservation. In five mixed European beech-silver fir forests of Central Italy (Tuscany and Marches), classified as priority habitats of the Natura 2000 Network, we analysed the climate-growth relationships of silver fir ( Abies alba Mill.) along an altitudinal gradient. The aims of this study were: i) to identify the main spatial patterns in the frequency domain of both silver fir growth and climate variables in five different sites and ii) to detect the overall climate sensitivity of the target species through time. Multivariate analysis displayed groups of chronologies with similar growth patterns for each frequency band-pass, discriminating for altitude and geographical location. The spectral density of climate variables at seasonal scale displayed common spatial patterns during late-spring and summer months. In stands where fir grows in optimal conditions, the most significant growth responses to climate were the positive influence of late-spring and summer precipitations of the previous year and the negative effect of summer temperatures of both previous and current year, although decreasing during the last decades. On the other hand, the site at lowest altitude shows a low and not very consistent climate sensitivity as compared to the preferred altitudes. At the highest site (1375 m asl) the positive effect of previous year spring–summer precipitation and summer temperature of both previous and current year disappears. Re**sults suggest that in the studied areas a water-use increase in summer is a possible response of silver fir to the significant reduction of spring precipitation and general temperature increase throughout the 20th century. These findings provide additional information on silver fir responses to climate variability at different altitudes, useful for calibrating silvicultural treatments to apply for conservation of sensitive ecosystems and of tree species in mountain areas.

Description: Publication date: Available online 27 June 2014 Source: Dendrochronologia Author(s): Gretel Boswijk , Duncan Munro , Martin J. Jones The interpretation of felling dates established by dendrochronological dating requires understanding of sample context and building practices, as well as knowledge of processes and timescales within the timber supply chain. In New Zealand (N.Z.), tree ring analysis of kauri from colonial-era (1840-1906) and early Dominion-era (1907-1920) buildings has been undertaken since 2000 and felling dates have been identified from several structures, providing a terminus post quem date for construction or modification of the building. What has been lacking is a good understanding of how long it took for a kauri tree to become timber used in a building or other structure. As a first estimate, felling dates from a small set of buildings were compared to documented construction dates, suggesting a delay of up to five years. To improve interpretation of felling dates, we investigated timescales associated with two stages of timber production within the 19 th and early 20 th century kauri timber industry: (a) transportation from stump to mill, and (b) seasoning of sawn timber. Documentary sources for ∼1850 until the 1920s were analysed, covering the development, expansion and decline of industrialised kauri timber production. The available evidence suggests that transportation to the sawmill was the most important variable. Logs could arrive within a few weeks of felling or potentially experience a delay of a year or more. Transportation times were affected by geography, weather, spatial differences and temporal changes in transportation methods and economic fluctuations. Seasoning of sawn timber probably contributed little to the time lag, as the balance of evidence suggests framing timber was not usually seasoned. In general, any delay associated with transportation and seasoning is unlikely to be more than a couple of years. The findings support the earlier use-date range of up to five years, but suggest it is generous. The dating of waney-edge timbers from buildings with accurate construction dates would help refine a use date range for kauri, as would further research into other stages of the production process including conversion of logs, transportation to market, and stockpiling in the timber yard and/or building site. The current study is also a starting point for further research in three related areas: (a) biography of timber; (b) technological change; and (c) trade networks.

Description: Publication date: Available online 9 May 2014 Source: Dendrochronologia Author(s): Mathieu Decuyper , Perry Cornelissen , Ute Sass-Klaassen Dendrochronology was used to assess the influence of soil conditions, elevation and related inundation, climate fluctuations and vegetation cover on the establishment and growth of hawthorn in non-grazed river floodplains. Presence of forest influences the discharge capacity of the floodplain, therefore forest development needs to be considered in management plans. Although ring detection in hawthorn is difficult, clear dynamics in establishment and growth of this shrub species were found. Establishment was mainly influenced by inundation (length and height). The effect of inundation on establishment is location dependent; positive due to transport and deposition of seeds in higher areas, and negative due to drowning of young plants in lower locations. Extreme climatic events were found to influence establishment including a drought in 2003 and relatively low and high precipitation in 2004-2006 and 2007 respectively. These events combined with almost no inundation caused some anomalies in the time series for hawthorn establishment. Once above a certain height, hawthorn is able to withstand various abiotic disturbances occurring in these dynamic river floodplains. Excavated areas are enhancing forest development following hawthorn establishment and therefore these areas should be limited in size (e.g. by deeper and narrower excavations and thus a steeper transition towards the grasslands).

Description: Publication date: 2014 Source: Dendrochronologia, Volume 32, Issue 2 Author(s): Beatriz Vidondo

Description: Publication date: Available online 29 May 2014 Source: Dendrochronologia Author(s): Piermattei Alma , Garbarino Matteo , Urbinati Carlo European black pine ( Pinus nigra ssp. nigra Arnold) encroachment at increasing elevation has been analysed at four treeline ecotones of the central Apennines (Italy). The study sites are located along a North-South gradient of 170 km across Marche and Abruzzo regions in Central Italy. The aims of this study were: i) to detect possible common patterns of structural attributes of black pine regeneration at the treeline ecotone; ii) to date the seedlings germination and iii) to assess the climate influence on the pine upward encroachment process also using intra-annual density fluctuations (IADFs) in tree-rings. We sampled 658 encroached black pine trees above the current treeline to the mountain top. All individuals were mapped and their basal stem diameter, total height, annual height increments and other structural attributes measured. One increment core was extracted from stem base of most samples for cambial age determination and detection of intra-annual density fluctuations (IADF). At two sites we also extracted cores at DBH from forest trees to assess climate-growth relationships of black pine. We used multivariate analysis (PCA) to explore the correlation structure of the main tree attributes, regression analysis to relate radial and height increment and dendroclimatic analysis to assess the influence of climate on tree growth and IADF formation. Most black pine trees were located at high altitude and their structural attributes were similar at the four sites where the pine encroachment process started between 30 and 40 years ago featuring similar germination peaks and growth patterns. Black pine is particularly sensitive to maximum temperatures and IADF occurred in mid-late summer with highest frequency peaks between 2003 and 2004. The pine encroachment process, besides the differences of environmental features and land use histories of the four study sites, appears synchronic and spatially diffused. Consistent tree-growth dynamics and the species adaptation to a warming climate are signals envisaging a possible treeline upward shift.

Description: Publication date: Available online 24 July 2014 Source: Dendrochronologia Author(s): Marc Wassenberg , David Montwé , Hans-Peter Kahle , Heinrich Spiecker Wood density is a trait of paramount importance for the assessment of wood quality, in dendroclimatology and in attempts to enhance biomass and carbon estimations. X-ray densitometry is the established but costly and time consuming method for high resolution measurements of wood density. An inexpensive and rapid alternative is High Frequency (HF) densitometry, which until now has only been yielding relative density variation profiles that were not calibrated to true volumetric mass density. This study examines the potential of calibration functions for density values obtained from HF scanning and compares the results to volumetrically determined true wood density and density derived from optical image analysis. We found that mean HF values of 112 stem discs of different tree species were highly correlated (R 2 of 0.9) to the samples’ true densities. Species specific calibration functions performed significantly better than a pooled model, whereas grouping according to basic wood anatomical types did not improve the model significantly. Prediction errors for species specific calibration functions were reasonably low ( S ( Y ˆ i ) 〈 5 % ). High resolution radial density profiles for 10 wood pieces of Norway spruce ( Picea abies ) obtained from HF densitometry calibrated with the species specific calibration function were highly correlated to density profiles obtained from optical image analysis of thin sections of the same samples. The mean densities obtained from the two different methods did not differ significantly. Thus it could be shown that values from HF densitometry can be calibrated to true density and therefore produce comparable density chronologies and be used as a proxy to predict wood quality parameters as well as for assessment of biomass.

Description: Publication date: Available online 22 July 2014 Source: Dendrochronologia Author(s): Feng Chen , Yu-jiang Yuan , Wen-shou Wei , Tong-wen Zhang , Hua-ming Shang , Ruibo Zhang We developed six tree-ring width chronologies of Siberian spruce ( Picea obovata ) from the low elevation forest of the southern Altay Mountains in northern Xinjiang, China. Although the six chronologies come from different sampling sites, significant correlations existed among the chronologies ( r ≥ 0.477), and the first principal component (PC1) accounted for 72.2% of total variance over their common period 1825–2010. Correlation response analysis revealed that radial growth of Siberian spruce is mainly limited by a 12-month precipitation starting from July of the previous year to June of the current year. We therefore developed a July–June precipitation reconstruction spanning 1825–2009, which explained 65.5% of the instrumental variance for the period 1962–2009. The information of our precipitation reconstruction suggested that dry conditions existed for the periods 1829–1838, 1852–1855, 1876–1888, 1898–1911, 1919–1923, 1932–1936, 1943–1955, 1963–1968, 1973–1984 and 2007–2009, and wet conditions for the periods AD 1825–1828, 1839–1851, 1856–1875, 1889–1897, 1912–1918, 1924–1931, 1937–1942, 1956–1962, 1969–1972 and 1985–2006. Spatial climate correlation analyses with gridded land surface data revealed that our precipitation reconstruction contains a strong precipitation signal for the Altay Mountain ranges. Our reconstruction agreed with the moisture-sensitive tree ring width series of Siberian larch from the Altay Mountains of Mongolia on a decadal timescale. In addition, in contrast to a drying trend in north central China, a clear wetting trend has occurred in the southern Altay Mountains since 1980s.

Description: Publication date: Available online 27 July 2014 Source: Dendrochronologia Author(s): Allan Buras , Martin Wilmking Shrub dendrochronological investigations are recently gaining more and more importance within the dendro-scientific community. As being a rather young discipline, many means of shrub dendrochronology lean on established methods that have been developed for trees. Although shrubs as trees are woody plants, it seems likely that they express differing growth characteristics due to their often multi-stemmed and prostrate stature. Yet, the majority of shrub dendrochronological investigations have measured shrub ring widths along two radii within one (sometimes several) stem disc(s) per individual. To our knowledge only one study so far has undertaken the approach to measure complete area increments (e.g. basal area increments, if applied to the basal stem disc of a shrub), however not focusing in detail on a comparative evaluation of this new approach with respect to radial measurements. To fill this knowledge gap our study focuses on the comparison of stem disc area increment measurements with radial measurements in the context of shrub growth representation and response- and transfer-function analyses. Our results indicate that for eccentric shrubs a minimum of four radial measurements per stem disc should be obtained for a good representation of the average stem disc growth. Inter-stem-disc comparisons showed that growth differences between individuals were often misestimated when only based on one or two radial measurements per stem disc. Response- and transfer-function analyses suggested, that the investigated shrubs reflect different environmental signals within different sectors of stem discs. This implies to carefully select radial measurements and individuals to increase the strength of environmental signals within transfer functions.

Description: Publication date: Available online 1 August 2014 Source: Dendrochronologia Author(s): C. Pritzkow , I. Heinrich , H. Grudd , G. Helle In this study, wood anatomy, tree-ring width and wood density of Pinus sylvestris at the northern timberline in Fennoscandia were used to identify relationships among the parameters and to screen them for their climatic signals. Furthermore we investigated the influence of the juvenile wood section for all parameters developed. The measurements of wood anatomy were conducted with confocal laser scanning microscopy (CLSM) while the density profiles were produced using an Itrax MultiScanner. We developed chronologies of ring width, wood density and anatomy for a period between 1940 and 2010. Correlations between wood density and wood anatomy were strong in the latewood part. For some wood anatomy and density chronologies youth trends were found in the juvenile part. Wood density decreased from the pith up to the 9 th ring and stabilized afterwards, while cell lumen diameter and lumen area increased simultaneously up to the 15 th ring. All chronologies contained strong summer temperature signals. The wood anatomical variables provided additional information about seasonal precipitation which could not be found in wood density and tree-ring widths. Our study confirmed previous results stating that the parameter maximum density contains the strongest climate signal, that is, summer temperatures at the northern timberline. Nevertheless, the intra-annual data on tracheid dimensions showed good potential to supply seasonal climatic information and improve our understanding of climatic effects on tree growth and wood formation.

Description: Publication date: Available online 9 July 2014 Source: Dendrochronologia Author(s): Xingyun Zhao , Ziwei Zheng , Zhiyuan Shang , Jian Wang , Ruiqin Cheng , Junlong Qian The Cryptomeria fortunei (CF) tree-ring δ 13 C p series, which was collected from the West Tianmu Mountain forestland (30°20′N, 119°26′E), located in the north-west of Zhejiang Province, China, belonging to the northern margin of the mid-subtropical region of Eastern China, were determined based on cross-dated tree-ring age. There was a significant decline in the δ 13 C p series occurring from 1685 to 1985, more especially from 1835 to 1985 in response to increasing atmospheric CO 2 concentrations and decreasing atmospheric δ 13 C a . To reduce the noise and enhance the climatic signals, we compared the polynomial function with the correction method developed by McCarroll and Loader (2004) to remove the low-frequency variation in the raw tree ring δ 13 C p series (defined as the δ 13 C poly series, δ 13 C cor series, respectively), and found the most suited correction method was the correction method developed by McCarroll and Loader (2004) in our study area. High-frequency correlation analysis between the δ 13 C cor series and many meteorological parameters recorded by Xian Rending weather station revealed that the current August-September mean maximum temperature and previous year mean minimum and mean maximum temperature(P〈0.005)most strongly influenced tree ring δ 13 C p discrimination from 1956 to 1985, and the strongest temperature signal captured was the current August-September mean maximum temperature(r = 0.54, P〈0.005). Mainly on this basis, the varied history of current August-September mean maximum temperatures in the West Tianmu Mountain area were reconstructed from 1685 to 1985. The reconstructed maximum temperatures revealed a slight warming trend and showed close correlation with the climatic fluctuations of the Little Ice Age cold period before 1900 as well as the 20th century warm period after 1900. It also better corresponded with some climate events recorded in historical records. Spectrum analysis showed that in the reconstructed series there was quasi-periodicity of 66.7yr, 21.1yr, 3.2yr, 2.3yr and 2.0yr. These cycles coincided with the “torque effect” variation of planets and the geocentric convergence, and changes in solar activity and irradiance, as well as the “Quasi-biennial oscillation” (QBO). This indicated that the δ 13 C p chronology of tree rings in West Tianmu Mountain showed a good record of the sun's activities, the change in the sun radiation and ENSO events.

Description: Publication date: Available online 31 January 2014 Source: Dendrochronologia Author(s): Ana Luísa Luz , Helena Pereira , Alexandra Lauw , Sofia Leal This study aims at monitoring the cambial activity and xylogenesis along the growing season under Mediterranean climate using a newly designed sampling method based on the periodic collection of twigs from the crown, in order to test its efficacy. Ten species were selected; seven hardwood ( Acer pseudoplatanus L .,Ceratonia siliqua L ., Schinus terebinthifolius Raddi , Olea europaea L ., Fraxinus angustifolia Vahl , Populus alba L., Quercus suber L.) and three softwood species ( Abies alba Mill ., Cupressus sempervirens L ., Pinus pinea L.). The twigs were collected monthly during one year. After microtome sectioning and staining, the sections were photographed and analyzed to monitor ring development and the period of cambial activity. The twigs revealed large differences in radial growth, within and among species, which might be associated to their particular position in the tree, to the effect of the different crown microclimates, and/or to the crown conformation and type of leaves. The method showed effectiveness in the study of cambial activity, but limitations in the study of ring development due to impossibility of comparing samples. Improvements to the method are proposed, aiming essentially at minimizing the variability among samples.

Description: Publication date: Available online 12 February 2014 Source: Dendrochronologia Author(s): Flurin Babst , Olivier Bouriaud , Ross Alexander , Valerie Trouet , David Frank The use of tree-ring data in carbon cycle research has so far been limited because traditional study designs are not geared towards quantifying forest carbon accumulation. Existing studies that assessed biomass increment from tree rings were often confined to individual sites and used inconsistent sampling schemes. We applied a consistent biomass-oriented sampling design at five managed forest sites located in different climate zones to assess the annual carbon accumulation in above-ground woody tissues (i.e. stems and branches) and its climate response. Radial growth and biometric measurements were combined to reconstruct the annual biomass increment in individual trees and upscaled to the site level. In addition to this, we estimated that 32-60 trees are required at these five sites to robustly quantify carbon accumulation rates. Tree dimensions and growth rates varied considerably among sites as a function of differing stand density, climatic limitations, and management interventions. Accordingly, mean site-level carbon accumulation rates between 65 g C m −2 y −1 and 225 g C m −2 y −1 were reconstructed for the 1970-2009 period. A comparison of biomass increment with the widely used basal area increment (BAI) revealed very similar growth trends but emphasized the merits of biomass assessments due to species-specific BAI/biomass relationship. Our study illustrates the benefits and challenges of combining tree-ring data with biometric measurements and promotes the consistent application of a standardized sampling protocol across large spatial scales. It is thus viewed as a conceptual basis for future use of tree-ring data to approach research questions related to forest productivity and the terrestrial carbon balance.

Description: Available online 4 April 2013 Publication year: 2013 Source: Dendrochronologia The summer North Atlantic Oscillation (SNAO), derived from the first EOF of mean sea level pressure over the extratropical North Atlantic in July and August, has a close association with climate variability over the North Atlantic region, and beyond, on both short and long time scales. Recent findings suggested a teleconnection, through the SNAO, linking climate variability over Northern Europe with that of East Asia in the latter part of the twentieth century. Here we investigate the temporal stability of that teleconnection for the last four centuries using 4261 tree-ring width series from 106 sites and, additionally, ten climate reconstructions from East Asia. Our results showed a great potential in using tree-ring width (TRW) data to extend analyses of the SNAO influence on East Asian climate beyond the instrumental period, but preferably with a denser network. The strongest SNAO-TRW associations were found in central East Asia (in and around Mongolia) and on the eastern edge of the Tibetan Plateau. In addition, the analysis showed that the association between the SNAO and East Asian climate over the last 400 years has been variable, both among regions and at specific sites. Moreover, a clear difference in the SNAO-TRW associations was found on two examined time scales, being stronger on longer timescales. Our results indicate that TRW data can be a useful tool to explore the remote influence of the SNAO on East Asian climate in the past.

Description: Publication date: Available online 26 September 2013 Source: Dendrochronologia Author(s): Stella Bogino In 1931, Krebs and Fischer, published El pluviómetro secular (The centenary pluviometer) an analysis of tree rings of Prosopis caldenia Burkart (caldén) in the central Argentinean Pampas which, according to the date, may be considered as one of the first dendrochronological studies in South America.

Description: Publication date: Available online 10 December 2013 Source: Dendrochronologia Author(s): Inga Labuhn , Valérie Daux , Monique Pierre , Michel Stievenard , Olivier Girardclos , Anaïs Féron , Dominique Genty , Valérie Masson-Delmotte , Olivier Mestre A main concern of dendroclimatic reconstruction is to distinguish in the tree ring proxy the influence of the climate variables of interest from other controlling factors. In order to investigate age, site and climate controls on tree ring width and cellulose δ 18 O, measurements have been performed in nearby groups of young (145 years old) and older (310 to 405 years old) oak trees in south-western France, covering the period 1860-2010. Within a given site, inter-tree deviations are small, pointing to a common climatic signal. Despite a similar inter-annual variability, the average level of cellulose δ 18 O in the young tree group is ∼0.8‰ higher than in the old trees. Such offsets might be caused by different soil properties and differences in the fraction of the source water used by trees from different depths. The δ 18 O of water in the top soil layer is directly related to the current growing season precipitation, while deeper water can have a lower and more constant δ 18 O. Local cave drip waters at 10 m depth indeed show a constant isotopic composition, which corresponds to pluri-annual mean precipitation. A 2‰ increasing trend is observed in cellulose δ 18 O of young trees in the first 30 years of growth, during a period when no trend is visible in older trees. This increase can be quantitatively explained by humidity gradients under the forest canopy, and a changing microclimate around the crown as trees grow higher. While relationships between tree ring width and climate appear complex, the isotopic composition of cellulose is strongly correlated with summer maximum temperature, relative humidity and evapotranspiration (r ≈ 0.70). Weaker correlations (r ≈ 0.40) are identified with precipitation δ 18 O from a 15-year long local record and from the REMOiso model output. These results imply that leaf water enrichment has a stronger control on the inter-annual variability of cellulose δ 18 O than the δ 18 O of precipitation. This study demonstrates the suitability of oak tree ring cellulose δ 18 O for reconstructing past summer climate variability in south-western France, provided that the sampling and pooling strategy accounts for the fact that trees from different sites and of different age can introduce non-climatic signals.

Description: Publication date: Available online 11 October 2013 Source: Dendrochronologia Author(s): Johannes Edvardsson , Thomas W.D. Edwards , Hans Linderson , Dan Hammarlund Comparison between growth variability, based on ring-width (RW) analysis, and moisture-sensitive signals in tree-ring carbon and oxygen stable-isotope composition provides increased understanding of how climate and hydrology influenced bog pines (Pinus sylvestris L.) at two sites in southern Sweden during the mid- and late Holocene. Tree-ring sequences from two subfossil trees collected at raised bogs having different hydrology and catchment size were analysed to probe the stable-isotope signals associated with two bog-wide episodes of growth depression, one during the Holocene Thermal Maximum and the other during the Neoglacial Transition. The occurrence of lower whole-wood δ 13 C and cellulose δ 13 C and δ 18 O values immediately prior to the onset of growth depression in both trees, suggesting increased atmospheric relative humidity, is consistent with the notion that excessive effective moisture impeded tree growth. Correlation analysis indicates that the growth response lagged about three years behind the decline in δ 13 C and δ 18 O values in each tree, possibly reflecting relatively slow rise in the local water table in response to wetter climate.

Description: Publication date: Available online 4 October 2013 Source: Dendrochronologia Author(s): Holger Gärtner , Sandro Lucchinetti , Fritz Hans Schweingruber The variability of wood anatomical features in the rings of trees and shrubs is known to be dependent on multifaceted environmental parameters. The ability to determine anatomical variations over longer time periods as decades or centuries is a step forward in dendroecological and dendroclimatological research. In this regard micro sectioning is still one of the basic requirements but sectioning devices (microtomes) designed for wood anatomical purposes are rarely available. We present an affordable heavy duty, but light-weight microtome operated with removable blades. This portable device enables the production of large sections for dendroclimatological reconstructions as well as various types of common sections for wood anatomical studies.

Description: Publication date: Available online 11 October 2013 Source: Dendrochronologia Author(s): Yun Zhang , Igor Drobyshev , Lushuang Gao , Xiuhai Zhao , Yves Bergeron We used dendrochronological methods to study disturbance history of a mixed Korean pine ( Pinus koraiensis Siebold et Zuccarini) dominated forest on the northern slope of Changbai Mountain, North Eastern China, over 1770-2000. Frequent small-scale canopy gaps and infrequent medium-scale canopy disturbances dominated natural disturbance regime in the forest, which didn’t experience stand-replacing disturbances over the studied period. Percentages of growth releases in subcanopy trees were below 6% in most decades, suggesting that disturbances initiating these releases were of low intensity. Strong winds were likely cause of moderate disturbance events. Two episodes with increased disturbance rates (19% and 13%) were dated to the 1920s and 1980s, timing of the 1980s event was consistent with a hurricane occurred in 1986 on the western slope of the Changbai Mountain. Age structure and growth release analyses revealed species-specific regeneration strategies of canopy dominants. Shade-intolerant Olga bay larch ( Larix olgensis Henry) recruited mainly before the 1860s. Recruitment of moderately shade-tolerant P. koraiensis occurred as several regeneration waves (1820s, 1850s, 1870-1880s, 1930s, and 1990-2000s) of moderate intensity. Shade-tolerant Jezo spruce ( Picea jezoensis Carr. var. komarovii (V.Vassil.) Cheng et L.K.Fu) and Manchurian fir ( Abies nephrolepis (Trautv.) Maxim.) regenerated continuously over the last 220 and 130 years, respectively. Enhanced recruitment of P. koraiensis , P. jezoensis , and A. nephrolepis was observed during the 1930s and 1990s, coinciding with increased growth release frequency in the 1920s and 1980s, and suggesting disturbance events of moderate intensity. Our results indicate that the current disturbance regime of the mixed Korean pine dominated forest maintains coexistence of light-demanding and shade-tolerant species and that change in wind climate may be particularly important for future forest composition.

Description: Publication date: 2013 Source: Dendrochronologia, Volume 31, Issue 3 Author(s): Yu-jiang Yuan , Tong-wen Zhang , Wen-shou Wei , Daniel Nievergelt , Anne Verstege , Shu-long Yu , Rui-bo Zhang , Jan Esper Three tree-ring maximum latewood density chronologies were developed from high elevation Picea schrenkiana sites in the western Tien Shan Mountains using different detrending methods. The new chronologies extend back to the early 16th and late 17th centuries, and contain significant late spring and summer temperature signals, respectively. An assessment of varying detrending methods and band-pass filtering the chronologies revealed only slightly differing low frequency trends retained in the maximum latewood densities. The distance between sampling sites and the varying seasonality of limiting climatic factors are identified as key drivers affecting the correlation among the maximum latewood density records in the study region. The new chronologies represent reliable proxies of high elevation late spring and summer temperature variability in an area underrepresented by such data, and are ready-to-use for network analyses addressing longer-term climate variations in eastern central Asia.

Description: Publication date: 2013 Source: Dendrochronologia, Volume 31, Issue 3 Author(s): Marín Pompa-García , Julián Cerano-Paredes , Peter Z. Fulé Climate change could modify the biogeography of many forest species. Elevational gradients have been documented as strategic sites to better understand tree growth response to regional climate variables. Pinus cooperi Blanco is one of the most important species in Northern Mexico. However, little is known concerning effects of climate responses on growth of this species. We used tree data records to compare the influence of precipitation and temperature on radial growth among P. cooperi populations across a mountain landscape at elevation gradient. Correlation and regression analysis of the regional growth–climate relationships showed that radial growth was correlated with previous winter conditions at most sites along the gradient. Wet and cold winters were positively associated with radial growth. Although our results showed significant climate influences on tree radial growth, other site factors also may have affected growth–climate responses. The results support the idea that climate change influences P. cooperi growth.

Description: Publication date: 2013 Source: Dendrochronologia, Volume 31, Issue 3 Author(s): T.P. Fournier , G. Battipaglia , B. Brossier , C. Carcaillet Aleppo pine ( Pinus halepensis Mill.) is adapted to fire, the most important disturbance in Mediterranean ecosystems. This species is known to be sensitive to fire and is usually killed when burned, but has a powerful regenerative capacity following burning. Sometimes, however, pines survive within burned areas, suggesting a certain potential for recording fire events in terms of age-structure and eventually scars. In the present study, fire scars on Aleppo pine trunks were used to construct a 150-year fire record in a burned forest in southern France. Four fires were detected with a mean fire return interval of 27 years: minimum 13 years and maximum 45 years. The age structure of the Aleppo pine population was analyzed on the basis of dated fire-scars in order to test the role of fire in creating the polymodal structure of the pine population. Results show the presence of multiple “cohorts” (subpopulations) of Aleppo pine. There appear to have been several pulses of tree recruitment, with the two largest cohorts corresponding to regeneration after the 1919 and 2000 fires. Other fires were recognized based on fire scars but these were not associated with obvious post-fire pine recruitment. Regeneration success is likely to depend on fire severity and on the length of fire-free intervals. Fire history and associated age-structure can thus be reconstructed using Aleppo pine stands.

Description: Publication date: 2013 Source: Dendrochronologia, Volume 31, Issue 3 Author(s): Kara J. Pitman , Dan J. Smith The growth of mountain hemlock trees in Pacific North America demonstrates a complex relationship to two or more seasonal environmental variables. In order to examine the radial growth response of mountain hemlock to subseasonal climate variables, ring-width and X-ray densitometric analyses were used to construct intra-annual dendroclimatic records. The intent was to highlight the difference between the dendroclimatic outcomes of standard ring-width analyses to those derived from density chronologies collected at high elevation locations in the British Columbia Coast Mountains. This study highlights the importance of using multiple tree-ring parameters to better define the complex growth behaviour in mountain hemlock trees for the construction of more robust proxy climate records. Tree-ring chronologies from three sites were used to describe the inherent climate-growth trends. Maximum tree-ring density values provided a robust data series for constructing site-specific proxy records of late-summer temperature. Annual ring-width measurements provided independent proxies of spring snowpack trends. Significant decreases in temperature and an increase in snowpack depth during the early 1700s and early 1800s coincides with documented PDO phases and Little Ice Age glacier advances. Identification of early and late growing season climate signals within mountain hemlock trees demonstrates the value of documenting the characteristics of multiple tree ring parameters in future dendroclimatic studies.

Description: Available online 16 March 2013 Publication year: 2013 Source: Dendrochronologia On the basis of a significant correlation between the tree-ring width series from Changling–Shoulu (CLSL) in north-central China and observed instrumental data, the annual total precipitation of the previous July to the current June was reconstructed since 1853 for the studied region, with the predictor variables accounting for 41.2% of the variance in the precipitation data. Distinct wet periods with precipitation levels greater than the mean (315 mm) occurred in 1864–1876 and 1934–1960. Notable dry periods with precipitation less than the mean occurred in 1877–1888 and 1923–1933. The precipitation fluctuated dramatically during 1940–1970, and became relatively stable around the mean value from 1960. The CLSL precipitation series showed significant correlations with precipitation reconstructions from Mt. Xinglong, Mt. Helan, Ningwu and eastern China, suggesting that these five rainfall curves represent the general precipitation variations in the western-central environmentally sensitive zone of northern China. The calculations of the CRU grid points also indicate the existence of significant spatial correlation among these sites. Periodicity analysis showed clear 23.33-, 8.24-, 2.64- and 2.59-year cycles at a 99% confidence level for the reconstructed series during the past 155 years.

Description: Available online 15 March 2013 Publication year: 2013 Source: Dendrochronologia Based on the tree-ring width chronology of Sabina przewalskii Kom., a 450-year Palmer Drought Severity Index (PDSI) series was reconstructed in the middle Qilian Mountains, northeast Tibetan Plateau. During the calibration period of 1957–2004, the predictor variable accounts for 47% of the variance in the modeled PDSI data. There were three sustained severe multiyear droughts during the periods of 1705–1723, 1814–1833, and 1925–1941 before the instrumental period of 1957–2004, while no drought event lasting longer than 10 years occurred during the instrumental period. Although the modeled PDSI during the 1957–2004 period adequately assessed the intensity of the multiyear droughts for the last 450 years, the potential for prolonged droughts was underestimated. In the multidecadal scale, the drought of 1640–1730 had the greatest magnitude and the longest duration, the drought of 1808–1846 had the highest intensity, and the drought of 1917–1973 was moderate. Both the multiyear and decadal scale droughts in the middle Qilian Mountains corresponded to the droughts in the northeast Tibetan Plateau, demonstrating that drought occurrences in the northeast Tibetan Plateau are synchronous in decadal to multidecadal scales. The drought variations in the middle Qilian Mountains have significant periodicities of 2.05–2.31, 54.44, 98, and 122.5 years at a 99% confidence level.

Description: Available online 14 March 2013 Publication year: 2013 Source: Dendrochronologia In this study, we present the results of a dendroclimatological investigation of three coniferous tree species, Larix principis-rupprechtii , Picea meyeri and Pinus tabulaeformis , growing along an altitudinal gradient at the Lüliang Mountains in Northern China. Totally five tree-ring width chronologies were developed to explore the climate-growth responses of these tree species. No obviously regular trend associated with the increase of elevation was found by comparing the statistical characteristics of the chronologies. Correlation analysis indicated that the chronologies from lowerest to middle-high sites (SZ, BWD, BDGL and BDGP, respectively) were highly correlated, and different species from the same site showed the highest correlation. Growth–climate analysis indicated that the chronology of Larix principis-rupprechti at the uppermost site near the tree line (XWS) did not exhibit a significant response to the seasonal climatic factors, whereas the other four lower chronologies were consistently and significantly influenced by both the mean temperature from May to July and the total precipitation from March to June, regardless of tree species and elevation. The similarity of the tree growth–climate relationships of different species growing at different elevations (except that from the tree line) suggests that the trees in this region can provide common regional climate information, and combinations of multiple species (RC) are more successful in reconstructing the climate data than single species. The results of this research are very crucial for the future forest management and dendroclimatological sampling strategy in the arid to semi-arid area of northern China.

Description: Available online 15 March 2013 Publication year: 2013 Source: Dendrochronologia A two-step method to extract pure cellulose from tree rings is presented in this study. The method employs the reagents diglyme (diethylene glycol dimethyl ether), hydrochloric acid and sodium chlorite in a 6-h reaction using ordinary equipment. Through separation of the chemical compositions (monosaccharides) using liquid chromatography, the product of this method is shown to contain only glucose from pure cellulose. In contrast, the chemical composition of the “α-cellulose” extract obtained by the traditional Jayme–Wise method is primarily glucose and mannose, which may come from hemicelluloses. These results are also verified by comparing the stable carbon isotope ratio (δ 13 C), yields and percentage of carbon (C%) of the product extracted by this method and “α-cellulose” for different tree species. The results suggest that this method is simple, rapid and appropriate for processing large numbers of small wood samples to develop tree-ring isotope series for high-resolution paleoclimatic research with softwood trees.

Description: Available online 15 March 2013 Publication year: 2013 Source: Dendrochronologia While the forest-tundra zone in Siberia, Russia has been dendroclimatologically well-studied in recent decades, much less emphasis has been given to a wide belt of northern taiga larch forests located to the south. In this study, climate and local site conditions are explored to trace their influence on radial growth of Gmelin larch ( Larix gmelinii (Rupr.) Rupr.) trees developed on permafrost soils in the northern taiga. Three dendrochronological sites characterized by great differences in thermo-hydrological regime of soils were established along a short (ca. 100 m long) transect: on a river bank (RB), at riparian zone of a stream (RZ) and on a terrace (TER). Comparative analysis of the rate and year-to-year dynamics of tree radial growth among sites revealed considerable difference in both raw and standardized tree-ring width (TRW) chronologies obtained for the RZ site, characterized by shallow soil active layer depth and saturated soils. Results of dendroclimatic analysis indicated that tree-ring growth at all the sites is mostly defined by climatic conditions of a previous year and precipitation has stronger effect on TRW chronologies in comparison to the air temperatures. Remarkably, a great difference in the climatic response of TRW chronologies has been obtained for trees growing within a very short distance from each other. The positive relation of tree-ring growth with precipitation, and negative to temperature was observed in the dry site RB. In contrary, precipitation negatively and temperature positively influenced tree radial growth of larch at the water saturated RZ. Thus, a complicate response of northern Siberian larch forest productivity to the possible climate changes is expected due to great mosaic of site conditions and variability of environmental factors controlling tree-ring growth at different sites. Our study demonstrates the new possibilities for the future dendroclimatic research in the region, as various climatic parameters can be reconstructed from tree-ring chronologies obtained for different sites.

Description: Available online 17 March 2013 Publication year: 2013 Source: Dendrochronologia For both its climatic and ecological importance, Schrenk spruce ( Picea schrenkiana ) is a crucial tree species living at mid-altitude on the western area of the Tianshan Mountains. It plays a key role on understanding climatic change in the Tianshan Mountains in the past 500 years. However, whether the relationship between tree growth and limiting climate factors is stable over time is still not well-known. In this study, standard and residual chronologies of four 100-year age classes (AC1 〈 110a, 110a 〈 AC2 〈 210a, 210a 〈 AC3 〈 310a and AC4 > 310a) were established for detecting divergence in climate–growth relationships as well as comparing low-frequency and high-frequency variations. The results show that climate can account for a high amount of variance in tree-ring width and higher climate sensitivity was detected in younger trees. Younger trees (〈210a) exhibit significantly negative growth responses to mean monthly air temperature of previous June and positive relationship with total monthly precipitation of current April and May, while mean monthly air temperature of current March may inhibit growth of older trees (>210a). Tree-ring chronology statistics and response function reveal that the age-growth patterns are non-monotonic. Our results together with previous studies demonstrate that the age effects on tree-ring growth–climate response is attributed to a combination of genetic characteristics and site microclimate, which suggests that it is necessary to consider both age-dependent and species-specific climate responses when using tree-ring measurements as a proxy for valid climate reconstructions.