• The Dendroclimatological Potential of Willamette Valley Quercus garryana

      Gildehaus, S.; Arabas, K.; Larson, E.; Copes-Gerbitz, K. (Tree Ring Society, 2015-01)
      We develop a 341-year Oregon white oak (Quercus garryana Dougl.) tree-ring chronology in Oregon's Willamette Valley to evaluate climate-growth relationships and determine the species' dendroclimatological potential at our site and in the surrounding region. The standardized and residual chronologies exhibit significant positive correlations with previous-year April and May temperatures, inverse correlations with previous-year spring precipitation and summer PDSI, a positive correlation with current-year July precipitation and summer PDSI, and inverse correlations with current-year June temperatures. The strength of these relationships varies over time. Significant shifts in the chronologies' mean and variance align with phase changes in the Pacific Decadal Oscillation (PDO), with lower and more variable growth during the warmer, drier positive phase of the PDO over the instrumental record. The absence of similar shifts prior to the 1900s, suggests a lack of temporal consistency in the expression of PDO variability at our site. The strong crossdating at our site reflects a cohesive climate signal, and the climate analysis illustrates the potential to develop proxy data over multiple centuries. Together, these results indicate a potential to expand the network of currently available climate proxy data by utilizing Q. garryana in dendroclimatological research. © 2015 The Tree-Ring Society.
    • Morphological and Physiological Phenology of Pinus longaeva in the White Mountains of California

      Hallman, C.; Arnott, H. (Tree Ring Society, 2015-01)
      Natural variations and responses to climate change can be identified within climatically sensitive ecosystems by monitoring growing season events. In 1962-1964, Fritts conducted a phenologic study on Pinus longaeva in the White Mountains of California. He monitored growing season events, environmental data, and dendrometer readings. In this study morphological and physiological phenophases, dendrometer traces, and environmental data were collected throughout the summers of 2007 and 2008 in the White Mountains of California to better understand variability in Pinus longaeva phenology and identify any shifts in the growing season since the 1962-1964 study (Fritts 1969). As a result of a late-season snow storm, observable phenophases in 2008 were 12 days later than in 2007. Pollination onset was slightly earlier than in the 1962-1964, which may indicate that accumulated heat or a combination of environmental factors influence these phenophases. Duration and timing of cambial activity in the present study was similar to that recorded in the Fritts (1969) investigation despite a median summer temperature increase of at least 2°C. © 2015 The Tree-Ring Society.
    • How to improve dendrogeomorphic sampling: Variogram analyses of wood density using X-Ray computed tomography

      Guardiola-Albert, C.; Ballesteros-Cánovas, J.A.; Stoffel, M.; Díez-Herrero, A. (Tree Ring Society, 2015-01)
      Knowledge of the spatial heterogeneity of wood is useful for industrial applications and improving dendrogeomorphic sampling, because it allows a better understanding of 3-D wood density structure in tree stems damaged by geomorphic processes. X-ray computed tomography (XRCT) scanning as a means of non-destructive measurement has become an important technique in tree research as it allows the detection of internal variations in wood density. In this paper a new methodology for modelling spatial variations of relative wood density using variograms on XRCT images is developed. For each tree, XRCT images perpendicular to the stem axis were obtained with 1-mm spacing. In a first step, ImageJ software was used to process each image. Then, more than 30 one-dimensional variograms were studied for a selected number of cross-sections. The results show that there is a pattern in the diffusion of relative wood density linked to the attenuation of the geomorphic damage along the stem from the wounded area. Although the number of samples could be increased, these preliminary results demonstrate that variograms of XRCT are a useful tool to optimize dendrogeomorphic sampling, saving time and costs. © 2015 The Tree-Ring Society.
    • August to July Precipitation from Tree Rings in the Forest-Steppe Zone of Central Siberia (Russia)

      Shah, S.K.; Touchan, R.; Babushkina, E.; Shishov, V.V.; Meko, D.M.; Abramenko, O.V.; Belokopytova, L.V.; Hordo, M.; Jevšenak, J.; Kędziora, W.; et al. (Tree Ring Society, 2015-01)
      The goal of this research report is to describe annual precipitation reconstruction from Pinus sylvestris trees on three sites in the Abakan region, located in the Minusinsk Depression, at the confluence of the Yenisei and Abakan Rivers, Russia. The study was performed during the 4th annual international summer course "Tree Rings, Climate, Natural Resources and Human Interaction" held in Abakan, 5-19 August 2013. The reconstruction, for the 12-month total precipitation ending in July of the growth year, is based on a reliable and replicable statistical relationship between precipitation and tree-ring growth, and shows climate variability on both interannual and interdecadal time scales. The regional tree-ring chronology accounts for 56% of the variance of observed annual precipitation in a linear regression model, with the strongest monthly precipitation signal concentrated in May and June of the current growing season. Composite 500 mb height-anomaly maps suggest that the tree-ring data from this site, supplemented by other regional tree-ring data, could yield information on long-term atmospheric circulation variability over the study area and surrounding region. © 2015 The Tree-Ring Society.
    • Dendrochronological potential and productivity of tropical tree species in Western Kenya

      David, E.T.; Chhin, S.; Skole, D. (Tree-Ring Society, 2014-07)
      This study focuses on tropical tree growth rates in Western Kenya. The dendrochronological potential of each study species was determined by visual examination of rings, and then cumulative growth trajectories for diameter were synthesized for species of sufficient sample size (n ≥ 3), based on ring-width chronologies. The 14 tree species considered were: Acacia mearnsii, Bridelia micrantha, Combretum molle, Croton macrostachyus, Cupressus lustianica, Eucalyptus camaldulensis, Eucalyptus grandis, Eucalyptus saligna, Grevillea robusta, Mangifera indica, Markhamia lutea, Persia Americana, Syzygium cumini, and Trilepisium madagascariensis. The species with the highest dendrochronological potential included Acacia mearnsii, Cupressus lusitanica, the Eucalyptus spp. and Mangifera indica, which are all non-native species that successfully crossdated. The results also indicated that the species with highest dendrochronological potential had strong radial growth synchrony, which was reflected in high inter-tree correlation and (or) high growth variance explained by the first principal component axis. Furthermore, A. mearnsii and E. camaldulensis were sensitive to annual precipitation and moisture index. The species with the lowest dendrochronological potential were Grevillea robusta and Markhamia lutea. In terms of productivity, the three fastest growing species in the study, based on annual diameter increment, were Eucalyptus camaldulensis, Eucalyptus grandis, and Acacia mearnsii. This study also has great potential to extrapolate historical patterns of diameter growth to understanding annual aboveground biomass and carbon dynamics in Western Kenya.
    • An extractor device for stuck or broken increment borers

      Loader, N.J.; Waterhouse, J.S. (Tree-Ring Society, 2014-07)
      A lightweight, portable device for extracting stuck or broken increment borers is presented and its operation described. The “Decorum” extractor is compact and weighs less than 400 g. It is easily carried in a belt pouch or pocket and is both reliable and easy to operate. The extractor does not require fixed tie points nor does it damage the tree. It offers an effective solution to a widely occurring problem in dendrochronology and forest research.
    • Shifting climate sensitivity and contrasting growth trends in Juniperus species growing together at opposite range margins

      Riddle, J.; Pederson, N.; Stella, J.C.; Leopold, D.J. (Tree-Ring Society, 2014-07)
      The long generation time of woody plants inhibits detection of shifts in their distributions induced by climatic change. Consequently, assessing growth changes within existing populations, especially those near species range margins, can increase understanding of climate change impacts. We apply dendrochronological methods to examine recent radial growth of the ecologically similar species Juniperus communis L. and J. virginiana L. growing under the same conditions but at opposite latitudinal range margins. We use moving correlations to analyze changes in relationships between growth and monthly climatic variables, and regional curve standardization to identify trends in growth rate independent of plant age. For J. communis, growth sensitivity to temperature and precipitation shifted earlier in the spring whereas for J. virginiana only temperature sensitivity shifted earlier over the last 50 years. Since 1920, J. virginiana growth displays an upward trend, but J. communis growth shows both increases and decreases. Recent precipitation increase, rather than warming alone, appears to drive the growth trends, but interactions with temperature and vegetation dynamics, instead of range position, likely account for the differences in trends between species. Although these results generally agree with climate change predictions, they also point out potential difficulties in modeling future species ranges based on growth-climate relationships and growth at range margins.
    • Dendrochronological dating of the World Trade Center ship, Lower Manhattan, New York City

      Martin-Benito, D.; Pederson, N.; McDonald, M.; Krusic, P.; Fernandez, J.M.; Buckley, B.; Anchukaitis, K.J.; D'Arrigo, R.; Andreu-Hayles, L.; Cook, E. (Tree-Ring Society, 2014-07)
      On July 2010, archaeologists monitoring excavation at the World Trade Center site (WTC) in Lower Manhattan found the remains of a portion of a ship's hull. Because the date of construction and origin of the timbers were unknown, samples from different parts of the ship were taken for dendrochronological dating and provenancing. After developing a 280-year long floating chronology from 19 samples of the white oak group (Quercus section Leucobalanus), we used 21 oak chronologies from the eastern United States to evaluate absolute dating and provenance. Our results showed the highest agreement between the WTC ship chronology and two chronologies from Philadelphia (r  =  0.36; t  =  6.4; p < 0.001; n  =  280) and eastern Pennsylvania (r  =  0.35; t  =  6.3; p < 0.001; n  =  280). The last ring dates of the seven best-preserved samples suggest trees for the ship were felled in 1773 CE or soon after. Our analyses suggest that all the oak timbers used to build the ship most likely originated from the same location within the Philadelphia region, which supports the hypothesis independently drawn from idiosyncratic aspects of the vessel's construction, that the ship was the product of a small shipyard. Few late-18th Century ships have been found and there is little historical documentation of how vessels of this period were constructed. Therefore, the ship's construction date of 1773 is important in confirming that the hull encountered at the World Trade Center represents a rare and valuable piece of American shipbuilding history.
    • Tree-ring dating of historic buildings in Willsboro, northeastern New York, and development of regional chronologies for dendroarchaeology

      Barclay, D.J.; Rayburn, J.A. (Tree-Ring Society, 2014-07)
      Historical timbers have been sampled from buildings at 13 sites in Willsboro, New York, on the west shore of Lake Champlain. Ring-width series from 139 timbers have been successfully crossdated and used to develop tree-ring chronologies for ash (Fraxinus spp.), oak (Quercus spp.), pine (Pinus spp.), eastern hemlock (Tsuga canadensis (L.) Carr.), and spruce (Picea spp.), which collectively span A.D. 1555 to 1878. Tree cutting dates suggest that Windyview Manor was likely built in or soon after 1799, and a barn and farmhouse at the 1812 Homestead were built in or soon after 1812 and 1813, respectively. These dates are all consistent with documentary records for these sites. Aggregate data for the town suggest a shift in wood use for building during the 19th Century, with ash and oak commonly used for large frame timbers from the 1790s to 1820s, and hemlock and spruce dominating from the 1830s to 1860s. Chronologies developed in this project are among the first from historical timbers for northern New York and will facilitate further dendroarchaeological work in the region.
    • Dating hydrologic and geomorphic change using dendrochronology in Tully Valley, central New York: A summary

      Kappel, W.M. (Tree-Ring Society, 2014-07)
      This report summarizes the results of three case studies where dendrochronology was used to evaluate hydrologic and geomorphic change in parts of Tully Valley, in central New York, over the past 150 years. The case studies evaluate 1) the changes in water quantity and quality in a wetland area several miles north of an area of former solution-brine mining, 2) the development of recent bedrock fractures above former solution brine-mining areas, and 3) the development and timing of landslide movement. The advantage of contemporary dendrochronology is that tree-ring analysis can provide a background of hydrologic and geomorphic change when no direct documentation or data are available.
    • IN MEMORIAM—Elsie Winnifred Downey

      Tree-Ring Society, 2014-07
    • IN MEMORIAM—Won-Kyu Park

      Tree-Ring Society, 2014-07
    • IN MEMORIAM—James R. McClenahen

      Tree-Ring Society, 2014-07
    • Early days of dendrochronology in the Hudson Valley of New York: Some reminiscences and reflections

      Cook, E.R. (Tree-Ring Society, 2014-07)
      A brief and personal history of the development of dendrochronology in the Hudson Valley of New York in the 1970s and the quantitative reconstruction of climate from tree rings there is provided. Two people stand out in allowing that to happen. Marvin Stokes at the Laboratory of Tree-Ring Research sparked within me a deep and enduring interest in dendrochronology, and Daniel Smiley of Mohonk supported my interest in pursuing tree-ring research in the Shawangunk Mountains through his deep and curious love of its natural environment. The discovery of ancient trees growing in the Shawangunk Mountains, and their use in successfully reconstructing past drought there, truly launched my career as a dendroclimatologist and proved beyond doubt that dendroclimatology and the reconstruction of past climate could be successfully conducted in the northeastern United States.
    • Longitudinal variation of ring width, wood density and basal area increment in 26-year-old loblolly pine (Pinus taeda) trees

      Yu, M.; Cheng, X.; He, Z.; Wu, T.; Yin, Z. (Tree-Ring Society, 2014-07)
      Longitudinal variations in select wood quality parameters were examined in 26-year-old loblolly pine trees planted in Anhui Province, China. Wood density and ring width were measured from cross-sections of different heights of merchantable stems. The average ring width decreased from the base to 1.3 m, then increased to the maximum at 7.6 m, and thereafter reduced with stem height. The longitudinal patterns varied with cambial age in ring width. The coefficient of variation in ring widths along the stem height was greater than 21% at the cambial age 5–8 years and 9–12 years, and small variations were observed in other cambial age groups. The average wood density declined from 1.3 m to 7.6 m and then slightly increased with increasing stem height. The wood density showed great variation at different growth stages below 7.6 m, but varied less above 7.6 m. Basal area increment (BAI) gradually increased with increasing ring number (from the pith to the bark) at different stem heights, and markedly reduced after the 22nd ring. These results indicate that the longitudinal variations of wood density, ring width and BAI in loblolly pine are greatly affected by cambial age. The detailed information of the wood properties along stem heights could be useful to wood utilization of loblolly pine.
    • PREFACE-Tree-ring studies in New York State: Past and present

      Barclay, D.J.; Pederson, N.; Griggs, C. (Tree-Ring Society, 2014-07)
      New York State (NYS) has a long and significant history of tree-ring research. Some of the earliest dendroarchaeological and dendroclimatic work in eastern North America was done in NYS, and 1970s studies in Hudson Valley in the east of the state were important for demonstrating that drought records could be reconstructed from trees growing in humid environments. Some recent work in NYS is described in this issue of Tree-Ring Research, including tree-ring dating and provenancing of a boat in New York City, dendroarchaeological studies in a town in northeastern NYS, dendrogeomorphological work in central NYS, and a dendroclimatic investigation of two range-margin Juniperus species growing on alvars. The last of the five NYS papers in this issue provides a personal historical perspective on the beginnings of drought reconstructions in the Hudson Valley. There is considerable potential for future work in New York with extension of existing studies and work in new areas and with new tree species.