Now showing items 21-40 of 711

    • Crossdating Dead Trees: Does Sampling Height Influence Results?

      Angers, V.A.; Bergeron, Y.; Drapeau, P. (Tree-Ring Society, 2017-01)
      In trees experiencing stress prior to death, growth may be partially or totally suppressed, or may occur only in the upper part of the boles. This may induce inaccuracies when retrospectively crossdating dead trees. In this study, we investigated the occurrence and range of time lags between year of last ring production (YOLRP) in crossdated discs collected at the base, at breast height (BrH), and in the upper part (UP) of the boles of 145 snags and logs of four boreal species. We also assessed the influence of tree age and growth prior to death. When comparing YOLRP in the upper and lower part of trees, more than half the time lags departed from zero. Mean lags ranged from 0.6 to 4.6 years according to species, with lags up to 14 years. Negative time lags, i.e. ring production occurring in the lower part of boles while it has stopped in the upper part, were also observed in up to 26% of cases. We suggest that when reconstructing fine patterns of mortality where accuracy must be optimized, sampling entire discs at BrH should be considered, as well as sampling a disc in the UP when sampling old or slowly declining trees. © 2017 by The Tree-Ring Society.
    • Dendroclimatic Responses of Sugar Maple Tapped for Maple Syrup: A Case Study from Pennsylvania

      Copenheaver, C.A.; Dawson, D.E.; Garza, M.N.; Nemens, D.G. (Tree-Ring Society, 2017-01)
      Maple syrup is a regional, non-timber forest product in the United States that depends upon healthy, mature sugar maple (Acer saccharum Marshall). We examined whether tapping for maple syrup altered the dendroclimatic response of sugar maple. Ring width indices from two sites (tapped and reference) in central Pennsylvania were correlated with regional temperature, precipitation, and Palmer Drought Severity Index (PDSI). Both sites had significant correlations between summer and fall PDSI and radial growth. Spring PDSI was significantly correlated with growth at the reference site, but not at the tapped site. Both tapped and reference trees experienced below-average growth during years with dry spring conditions (PSDI < 0), but tapped trees had a higher percentage of years (27%) with below-average growth during years with moist spring conditions (PDSI > 0) compared to reference trees (15%). These results indicate that tapping for maple syrup may have altered the dendroclimatic response of sugar maple to moisture availability during the spring months. © 2017 by The Tree-Ring Society.
    • Dendrochronological Field Methods for Fire History in Pine Ecosystems of the Southeastern Coastal Plain

      Huffman, J.M.; Rother, M.T. (Tree-Ring Society, 2017-01)
      Few tree-ring based fire-history studies have been completed in pine ecosystems of the Southeastern Coastal Plain, in part because of difficulties in finding old fire-scarred material. We propose specialized field methods that improve the likelihood of locating fire scars in dead trees (i.e. stumps, snags, and logs). Classic fire-history field methods developed in the southwestern United States involve targeting only trees with evidence of repeated external scarring, but we have found this approach to be less effective in our region given that trees without any external scarring may contain an abundance of buried scars. The buried scars occur primarily near the ground surface and can be sampled by collecting full cross-sections from the bases of old dead trees. We hope our insights foster further fire-history research in the Southeastern Coastal Plain. © 2017 by The Tree-Ring Society.
    • Updating the Czech Millennia-Long Oak Tree-Ring Width Chronology

      Prokop, O.; Kolář, T.; Kyncl, T.; Rybníček, M. (Tree-Ring Society, 2017-01)
      In recent years, a millennia-long oak tree-ring width chronology, consisting of 3194 samples from 387 locations, was developed in the Czech Republic. Despite the collection of such a huge dataset, the replication in the 19th Century was very low and the natural oak distribution in the Czech Republic was insufficiently covered by recent samples, especially in Western Bohemia. This study aimed to remove these weaknesses, which have limited the paleoclimatic potential of this dataset, and to determine the number of sapwood rings, which is crucial for dendrochronological dating. Therefore, new recent samples were randomly collected at numerous sawmills along the Czech-German border. The historical material was usually sampled using a Pressler borer from church belfry constructions traditionally made from oak. In total, 252 recent and 90 historical tree-ring width series were incorporated into the chronology. The newly built chronology cumulatively consists of 3536 series, which covers the continuous period of A.D. 352-2014. The resulting tree-ring width record shows robust signal strength and homogeneous coverage of the territory. We show that the number of sapwood rings is constant over time. Therefore, we recommend using an estimate of 5-24 sapwood rings for a more precise dating of historical wood findings in the Czech Republic. © 2017 by The Tree-Ring Society.
    • The First Millennium-Age Araucaria Araucana in Patagonia

      Aguilera-Betti, I.; Muñoz, A.A.; Stahle, D.; Figueroa, G.; Duarte, F.; González-Reyes, Á.; Christie, D.; Lara, A.; González, M.E.; Sheppard, P.R.; et al. (Tree-Ring Society, 2017-01)
    • In Memoriam: Paul C. Van Deusen 1953–2015

      Sheppard, P.R. (Tree-Ring Society, 2017-01)
    • A Dendroecological Analysis of Forest Dynamics for Old-Growth Abies-Tsuga-Quercus on the Boso Peninsula, Southeastern Japan

      Abrams, M.D.; Umeki, K.; Bouma, C.; Nabeshima, E.; Toyama, K. (Tree-Ring Society, 2017-07)
      This study investigated the composition, age-and size-structure, and tree-ring relationships for an old-growth, warm-temperate, mixed-evergreen forest at the University of Tokyo Chiba Forest, Japan. A total of 32 tree species were recorded, which was dominated by Abies firma and Quercus acuta. Tsuga sieboldii dominated the recruitment after 1850, followed by Abies firma. After 1920, many individuals of Castanopsis, Cinnamomum, Cleyera and Quercus became established. The temporal pattern of conifer recruitment did not correspond to the record of strong wind events. Basal area increment in Abies firma and Castanopsis sieboldii trees increased throughout their lives, a trend not seen in the ring width index. Mean annual temperature was below the 100-year mean between 1920 and 1940 and 1960-1980, but increased rather abruptly after 1980. Mean annual precipitation decreased after 1960. Tree-ring releases are very common at the study forest, which are indicative of frequent small to moderate-sized disturbances. At least one release was recorded in every decade from 1890 to the present day, which is likely the primary causal factor promoting tree growth and recruitment. Our results suggest that early logging activities coupled with natural disturbances had a great influence on the developmental process and current structure of the study stand and that tree growth is varying in a manner consistent with forest dynamics. © 2017 by The Tree-Ring Society.
    • Survival Response of Larix Sibirica to the Tunguska Explosion

      Kletetschka, G.; Procházka, V.; Fantucci, R.; Trojek, T. (Tree-Ring Society, 2017-07)
      The disastrous Tunguska explosion (TE) in 1908 uprooted trees in a radial pattern. Several trees in this area survived and kept growing in the post-Tunguska environment. We collected samples from surviving trees (14 and 131 years old at the time of the TE) that lived until collection in 2008 and another sample from a control tree farther from the blast epicenter (germination in 1928), which were analyzed by X-ray fluorescence (XRF) and prompt gamma neutron activation analysis. Chemical composition of xylem tracheids of the surviving trees revealed several patterns potentially related to the TE. A calcium peak is associated with the 1908 ring in both of the exposed trees, but additional high concentrations in adjacent rings could represent enhanced translocation of Ca over the whole sapwood as a response to defoliation from the TE. Sr and Mn anomalies near 1908 appeared in one exposed tree but not in the other. High-resolution XRF indicates Ca as well as Zn anomalies are primarily located in the earlywood of the rings, whereas peaks in Mn, Zn and Cu are more associated with the latewood. A directional response was evidenced by a wider zone of elevated Ca in the rings on the southern side toward the airblast, which might have experienced the greatest defoliation and perhaps enhanced root damage as the tree was rocked by the pressure wave. The TE event in the middle of the 1908 growing season must have triggered tree responses to deliver more nutritive resources to the crown in order to hasten restoring new leaves in the crown and to aid in structural repair. © 2017 by The Tree-Ring Society.
    • A Method for Measuring Sub-Annual Ring Widths of Pinus Edulis for Seasonal Climate Reconstructions

      Matheus, T.J.; Maxwell, J.T.; Harley, G.L. (Tree-Ring Society, 2017-07)
      Pinus edulis is one of the most ubiquitous tree species in the US Southwest. It accounts for over a fifth of the total number of trees in New Mexico alone. Its prevalence and relatively long-lived nature makes it an ideal candidate for dendroclimatological studies of the North American Monsoon. The problem occurs with delineating the boundary of the earlywood and latewood for sub-annual reconstructions. In this study, we present a novel method ("the resin duct method") for delineating the latewood boundary using resin ducts of P. edulis from three sites in New Mexico. The climate sensitivity of partial ring widths of P. edulis is then explored and compared to co-occurring Pinus ponderosa, which has a clear latewood boundary. The method of using resin ducts for delineating latewood in P. edulis resulted in a statistically significant relationship when compared to the latewood widths of co-occurring P. ponderosa. Although we found a similar climate response of P. edulis when compared to P. ponderosa, P. edulis latewood was a poor predictor of North American Monsoon precipitation unlike P. ponderosa. However, P. edulis earlywood has a statistically significant correlation with cool-season precipitation, making it useful for cool-season climate reconstructions in the Southwest. © 2017 by The Tree-Ring Society.
    • A 1400-Year Bølling-Allerød Tree-Ring Record from the U.S. Great Lakes Region

      Panyushkina, I.P.; Leavitt, S.W.; Mode, W.N. (Tree-Ring Society, 2017-07)
      Since the late 19th Century, geologists and naturalists working in the US Midwest have reported an abundance of tree macrofossils embedded in glacial and lacustrine deposits formed after the Last Glacial Maximum. The most widely-known of these sites is the Two Creeks type locality in Wisconsin. We report progress on development of a long tree-ring record from this subfossil wood in the US Great Lakes region, employing samples collected during a decade-long series of field campaigns at recently eroded lake shorelines, construction projects, and excavations, along with acquisition of archived samples collected from the 1950s to the 1980s during past lake erosion events. A previously-reported tree-ring chronology from the Two Creeks type locality reached ca. 250 years in length; here we used radiocarbon dates and tree-ring crossdating to develop a 1408-year tree-ring chronology (mainly spruce Picea spp. with some tamarack Larix) comprising a total of 135 overlapped tree-ring width series in three clusters from nine locations in eastern Wisconsin. The calendar age of the record is estimated with 46 14C dates to between 14,500 to 13,100 cal BP. This is currently the oldest and only long tree-ring record in North America from the boreal environments of the Bølling-Allerød warm period during the transition from the Late Glacial to the Holocene. © 2017 by The Tree-Ring Society.
    • Identifying and Separating Pandora Moth Outbreaks and Climate from A 1500-Year Ponderosa Pine Chronology from Central Oregon

      Clark, P.W.; Speer, J.H.; Winship, L.J. (Tree-Ring Society, 2017-07)
      We reconstruct pandora moth (Coloradia pandora Blake) outbreaks and climate from a 1572-year (435-2006 CE) ponderosa pine (Pinus ponderosa Dougl. ex Laws.) chronology from a lava flow in central Oregon. We took samples from 128 living trees and remnant logs and crossdated the samples using skeleton plots and COFECHA for quality control. After cutting out and removing those time periods from the chronology during which insects become the main limiting factor to growth, we examine the response of tree rings to climate. Evidence of species longevity (up to 877 years), presence of periodic pandora moth defoliations (13 total), and a significant relationship with the Palmer Drought Severity Index were observed (R2 = 0.34, p &lt; 0.001). Suppressions related to pandora moth outbreaks were recorded back to 618 CE, with a mean return interval of 104 years. Previous-fall to current-spring PDSI was reconstructed over 1376 years (630-2006 CE), where the most prolonged drought periods were 1136-1166 CE and the Dust Bowl 1924-1941. Our research documents longevity of ponderosa pine, resilience in the presence of multiple disturbances, and demonstrates a technique to separate insect outbreak signals from climate reconstructions in long chronologies while embracing the entire signal available in tree rings. © 2017 by The Tree-Ring Society.
    • Towards A Better Chronology of Basque Heritage Using Time-Series from Renovation Waste

      Susperregi, J.; Jansma, E. (Tree-Ring Society, 2017-07)
      Dendroarchaeology in the Basque country is directed at improving our understanding of the cultural heritage preserved in, or originating from, northwestern Spain. To this end the emphasis is on the compilation of absolutely-dated tree-ring chronologies that can serve as a reference for accurately dating ancient structures such as buildings and shipwrecks. The current study focuses on 41 samples from radially-split oak planks that were mostly stored for reuse in a carpentry workshop in this region. The general consensus among historians is that these planks, and hence the buildings they are part of, date from the 15th and 16th Centuries. Our results show that the trees from which the planks were derived were cut down in the 15th to 19th Centuries, thus refuting this narrow time frame. The similarity of the planks' growth patterns to the annual variations of Basque chronology ARAB4 (AD 1277-1819), which we reworked slightly and renamed ARAB8, confirms that this chronology is well-suited for establishing the age of timbers preserved in the cultural heritage in this region. The inclusion of the new series into ARAB8 significantly improves the replication of this master chronology from ca. AD 1300 onwards and extends it forward to AD 1849. © 2017 by The Tree-Ring Society.
    • Using Dendrochronology to Investigate the Historical and Educational Value of two Log Structures at Bear Paw State Natural Area, North Carolina, USA

      Rochner, M.L.; Van De Gevel, S.; Spond, M.D.; Grissino-Mayer, H.D. (Tree-Ring Society, 2017-07)
      During May 2013, the Bear Paw State Natural Area near Boone, North Carolina acquired an 11.5 ha tract of land and two log cabins from David Wray of Blowing Rock, North Carolina. Work was soon underway to determine the historical nature of these two buildings and to evaluate them for consideration for the National Register of Historic Places. A historic structure report, completed as a collaboration between Appalachian State University and the North Carolina Division of Parks and Recreation, was unable to discover much about the history of the two log cabins except that they were both likely moved to their current location in the early 20th Century. To determine when the cabins were built, we extracted core samples from logs in both cabins and compared the tree-ring patterns to region-wide, precisely-dated reference chronologies. We dated the tulip poplar tree-ring chronology from the Big Cabin to the period 1675-1859. Cutting dates on several of the logs revealed tree harvest likely occurred between fall 1859 and spring 1860. Some logs had outermost rings that dated to 1857 and 1858. Still, these logs may have been harvested a few years earlier, or some of the outer rings may have been lost during construction or sampling. We were unable to absolutely date an 81-year long American chestnut chronology from the Small Cabin. Our results confirmed that the Big Cabin was an Antebellum Period structure (pre-American Civil War) and therefore has potential historical significance. Because we still cannot tie this cabin to a historical figure or a historical event, the cabin cannot be nominated yet for inclusion in the National Register of Historic Places, but the identification of an original construction date for the cabin may contribute to further assessment for inclusion on a local or national register. In the meantime, we intend to use this cabin in annual summer workshops for undergraduate students taking courses at Appalachian State University so that more students can be exposed to the hands-on nature of scientific inquiry and can learn the value of dendrochronology for understanding human and environmental history. © 2017 by The Tree-Ring Society.
    • Condition of Live Fire-Scarred Ponderosa Pine Twenty-one Years after Removing Partial Cross-Sections

      Heyerdahl, E.K.; McKay, S.J. (Tree-Ring Society, 2017-07)
      Concern over the effects of removing fire-scarred partial cross-sections may limit sampling of live ponderosa pine to reconstruct fire history. We report mortality rates for ponderosa pine trees 20 to 21 years after removing fire-scarred partial cross-sections to reconstruct fire history. In 2015, following surveys every five years since 2000, we revisited 138 trees that were alive when we sectioned them in 1994/95 and 386 similarly sized, un-sectioned neighbor trees of the same species that were also alive in 1994/95. Between 1994/95 and 2015, a significantly greater proportion of sectioned than neighbor trees died, yielding average annual mortality rates of 3.3% versus 2.2%. However, many of the trees that died were likely killed by prescribed fires in 2002 and 2003 (64 sectioned plus neighbor trees). When we excluded these trees to assess the effect of fire-scar sampling rather than the effect of modern fires, the difference in proportion of dead trees was no longer significant and yielded average annual mortality rates of 2.1% versus 1.4% for sectioned and neighbor trees. We continue to suggest that sampling live, fire-scarred ponderosa pine trees remains a generally non-lethal method of obtaining information about historical fires that can supplement the information obtained from dead fire-scarred trees. © 2017 by The Tree-Ring Society.
    • Notice: Bryant Bannister 1926–2016

      Dean, J.S.; Towner, R.H. (Tree Ring Society, 2016-07)
    • Meeting Report: The 2016 Ameridendro Awards

      Sutherland, K.E.; Mundo, I.A. (Tree Ring Society, 2016-07)
    • Application of the Minimum Blue-Intensity Technique to A Southern-Hemisphere Conifer

      Brookhouse, M.; Graham, R. (Tree Ring Society, 2016-07)
      Minimum blue-intensity (BI) appears to be a viable source of proxy-temperature data, but is yet to be applied to a Southern-Hemisphere species. Here, we apply the BI technique to Podocarpus lawrencei, a conifer endemic to the Australian Alps. We develop sample-preparation protocols and examine the climate sensitivity of resulting tree-ring width (TRW) and BI chronologies. We found that extractable resins were removed from P. lawrencei samples after 28 hours of Soxhlet extraction and a highly-significant negative correlation (r =-0.79, p<0.0001) exists between the resulting BI chronology and growing season (August-April) temperature maxima. The climate sensitivity of our BI data, combined with an apparent teleconnection with a previously-reported dataset, suggests that an unparalleled opportunity exists to develop a powerful proxy for growing-season temperatures in southeast Australia. © 2016 by The Tree-Ring Society.
    • Dendrochronology and the Complex History of the William Hawk Cabin, Salt Lake City, Utah

      Bekker, M.F.; Naylor, J. (Tree Ring Society, 2016-07)
      The William Hawk Cabin is considered one of the oldest pioneer structures in Salt Lake City, Utah. Tradition suggests that it was originally constructed in 1848 inside the "Old Fort" established by Mormon settlers in 1847, and then moved to its current location between 1850 and 1852. We examined tree rings from 23 Douglas-fir (Pseudotsuga menziesii var. glauca) and eight white fir (Abies concolor) timbers in the cabin to (1) evaluate and refine the suggested range of construction dates of 1848-1852, (2) verify or refute the suggestion that the cabin was originally constructed within the Old Fort, (3) identify any evidence of use of deadwood, timber re-use, stockpiling, or renovation, and (4) determine the provenance of the timbers. We built a 209-year floating chronology from 36 cores crossdated visually and verified statistically with COFECHA. Statistically significant (p < 0.0001) comparisons with established regional chronologies indicated that the Hawk Cabin chronology extends from 1651-1859. Cutting dates ranged from 1832-1860, with strong clusters in 1846 and 1851-1852, and a weaker cluster in 1855. The 1851-1852 cluster accounted for over half of the cutting dates, suggesting that a version of the cabin was built by 1852, and the later timbers were incorporated as part of a major renovation in or after 1860. The 1846 cluster may reflect wood salvaged from road building efforts by the Donner-Reed Party, and suggests that a version of the cabin may have been originally built in the Old Fort, although probably not by Hawk. These results confirm the historical significance of the William Hawk Cabin, and the complexity of its construction history argues for large sample depths in dendroarchaeological studies in semi-arid regions. © 2016 by The Tree-Ring Society.
    • Forgotten Waterways: Analyzing Beams from the Wabash and Erie Canal

      Taormina, R.; Speer, J.H. (Tree Ring Society, 2016-07)
      The Wabash and Erie Canal system was an important transportation network in the early 1800s prior to the dominance of trains and later automotive transportation. In this work, timbers from Culvert 151 were examined, after they were exhumed during construction of Hwy 641 on the south side of Terre Haute, Indiana. Cross-sections were taken from each of 22 beams and allowed to air dry to determine the stability of the timbers. We examined the wood to determine the genera or species of each sample that was used in this construction project and developed a floating chronology from our white oak group samples. The mix of species present included 11 beams of American beech (Fagus grandifolia), five white oak group (Quercus subgenus Lepidobalanus), and one each of American elm (Ulmus americana), winged elm (Ulmus alata), sugar maple (Acer saccharum), shagbark hickory (Carya ovata), white ash (Fraxinus americana), and black walnut (Juglans nigra). This suggests that the timbers were cut from the available trees in a certain size class without much regard for wood properties. The oak trees were an average of 186 years in age and the floating chronology dated to AD 1827. We also compared our chronology to 16 other oak chronologies in the region using an Inverse Distance Weighting (IDW) algorithm in ArcGIS to determine the most likely provenance of the samples. Our oak chronology correlates the strongest to archaeological samples from southeastern Indiana in Jefferson County along the Ohio River. It is possible that the timbers were cut near Madison Indiana, shipped down the Ohio River and up the Wabash River prior to incorporation in Culvert 151 on the Wabash and Erie Canal. © 2016 by The Tree-Ring Society.
    • Trends in Elemental Concentrations of Tree Rings from the Siberian Arctic

      Panyushkina, I.P.; Shishov, V.V.; Grachev, A.M.; Knorre, A.A.; Kirdyanov, A.V.; Leavitt, S.W.; Vaganov, E.A.; Chebykin, E.P.; Zhuchenko, N.A.; Hughes, M.K. (Tree Ring Society, 2016-07)
      The biogeochemistry and ecology of the Arctic environment have been heavily impacted by anthropogenic pollution and climate change. We used ICP-MS to measure concentrations of 26 elements in the AD 1300-2000 tree rings of larch from the Taymyr Peninsula in northern Siberia for studying the interaction between environmental change and wood chemistry. We applied a two-stage data reduction technique to identify trends in the noisy measurement data. Statistical assessment of variance of normalized time series reveals pronounced depletion of xylem Ca, Mg, Cl, Bi and Si concentrations and enrichment of P, K, Mn, Rb, Sr and Ba concentrations after ca. AD 1900. The trends are unprecedented in the 700-year records, but multiple mechanisms may be at work and difficult to attribute with certainty. The declining xylem Ca and Mg may be a response to soil acidification from air pollution, whereas increasing P, K, and Mn concentrations may signal changes in root efficiency and excess water-soluble minerals liberated by the permafrost thaw. The changes seem consistent with mounting stress on Arctic vegetation. This study supports the potential of tree rings for monitoring past and ongoing changes in biogeochemistry of Arctic ecosystems related to pollution and permafrost thaw. © 2016 by The Tree-Ring Society.