WorldWideScience

Sample records for annual tree rings

  1. Annually resolved atmospheric radiocarbon records reconstructed from tree-rings

    Science.gov (United States)

    Wacker, Lukas; Bleicher, Niels; Büntgen, Ulf; Friedrich, Michael; Friedrich, Ronny; Diego Galván, Juan; Hajdas, Irka; Jull, Anthony John; Kromer, Bernd; Miyake, Fusa; Nievergelt, Daniel; Reinig, Frederick; Sookdeo, Adam; Synal, Hans-Arno; Tegel, Willy; Wesphal, Torsten

    2017-04-01

    The IntCal13 calibration curve is mainly based on data measured by decay counting with a resolution of 10 years. Thus high frequency changes like the 11-year solar cycles or cosmic ray events [1] are not visible, or at least not to their full extent. New accelerator mass spectrometry (AMS) systems today are capable of measuring at least as precisely as decay counters [2], with the advantage of using 1000 times less material. The low amount of material required enables more efficient sample preparation. Thus, an annually resolved re-measurement of the tree-ring based calibration curve can now be envisioned. We will demonstrate with several examples the multitude of benefits resulting from annually resolved radiocarbon records from tree-rings. They will not only allow for more precise radiocarbon dating but also contain valuable new astrophysical information. The examples shown will additionally indicate that it can be critical to compare AMS measurements with a calibration curve that is mainly based on decay counting. We often see small offsets between the two measurement techniques, while the reason is yet unknown. [1] Miyake F, Nagaya K, Masuda K, Nakamura T. 2012. A signature of cosmic-ray increase in AD 774-775 from tree rings in Japan. Nature 486(7402):240-2. [2] Wacker L, Bonani G, Friedrich M, Hajdas I, Kromer B, Nemec M, Ruff M, Suter M, Synal H-A, Vockenhuber C. 2010. MICADAS: Routine and high-precision radiocarbon dating. Radiocarbon 52(2):252-62.

  2. Monthly paleostreamflow reconstruction from annual tree-ring chronologies

    Science.gov (United States)

    Stagge, J. H.; Rosenberg, D. E.; DeRose, R. J.; Rittenour, T. M.

    2018-02-01

    Paleoclimate reconstructions are increasingly used to characterize annual climate variability prior to the instrumental record, to improve estimates of climate extremes, and to provide a baseline for climate-change projections. To date, paleoclimate records have seen limited engineering use to estimate hydrologic risks because water systems models and managers usually require streamflow input at the monthly scale. This study explores the hypothesis that monthly streamflows can be adequately modeled by statistically decomposing annual flow reconstructions. To test this hypothesis, a multiple linear regression model for monthly streamflow reconstruction is presented that expands the set of predictors to include annual streamflow reconstructions, reconstructions of global circulation, and potential differences among regional tree-ring chronologies related to tree species and geographic location. This approach is used to reconstruct 600 years of monthly streamflows at two sites on the Bear and Logan rivers in northern Utah. Nash-Sutcliffe Efficiencies remain above zero (0.26-0.60) for all months except April and Pearson's correlation coefficients (R) are 0.94 and 0.88 for the Bear and Logan rivers, respectively, confirming that the model can adequately reproduce monthly flows during the reference period (10/1942 to 9/2015). Incorporating a flexible transition between the previous and concurrent annual reconstructed flows was the most important factor for model skill. Expanding the model to include global climate indices and regional tree-ring chronologies produced smaller, but still significant improvements in model fit. The model presented here is the only approach currently available to reconstruct monthly streamflows directly from tree-ring chronologies and climate reconstructions, rather than using resampling of the observed record. With reasonable estimates of monthly flow that extend back in time many centuries, water managers can challenge systems models with a

  3. Annual rings in a native Hawaiian tree, Sophora chrysophylla, on Maunakea, Hawai‘i

    Science.gov (United States)

    Kainana S. Francisco; Patrick J. Hart; Jinbao Li; Edward R. Cook; Patrick J. Baker

    2015-01-01

    Annual rings are not commonly produced in tropical trees because they grow in a relatively aseasonal environment. However, in the subalpine zones of Hawai‘i's highest volcanoes, there is often strong seasonal variability in temperature and rainfall. Using classical dendrochronological methods, annual growth rings were shown to occur in Sophora...

  4. Uranium mobility across annual growth rings in three deciduous tree species.

    Science.gov (United States)

    McHugh, Kelly C; Widom, Elisabeth; Spitz, Henry B; Wiles, Gregory C; Glover, Sam E

    2018-02-01

    Black walnut (Juglans nigra), slippery elm (Ulmus rubra), and white ash (Fraxinus americana) trees were evaluated as potential archives of past uranium (U) contamination. Like other metals, U mobility in annual growth rings of trees is dependent on the tree species. Uranium concentrations and isotopic compositions (masses 234, 235, 236, and 238) were analyzed by thermal ionization mass spectrometry to test the efficacy of using tree rings to retroactively monitor U pollution from the FFMPC, a U purification facility operating from 1951 to 1989. This study found non-natural U (depleted U and detectable 236 U) in growth rings of all three tree species that pre-dated the start of operations at FFMPC and compositional trends that did not correspond with known contamination events. Therefore, the annual growth rings of these tree species cannot be used to reliably monitor the chronology of U contamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Verification of annual growth rings in Egyptian trees by C-14 method

    International Nuclear Information System (INIS)

    Belacy, N.; Abou El-Nour, F.; Jacoby, G.C.

    1990-01-01

    Annual growth rings in trees were thought to be due to sharp seasonal variations in the precipitation rates during the year. Accordingly temperature zone trees such as Egyptian trees were supposed to be away from this phenomenon. The temperature zones which are meant here are those of no sharp seasonal variations in the precipitation rates. The present study applied carbon-14 dating to prove that the growth rings in some Egyptian trees are annual. The method was based on the tropospheric measurements of C-14 during the period 1954-1981. C-14 exhibited a sharp peak resulting from the ever greater series of nuclear tests during 1963-1965. The presence of this peak for Egyptian trees proved that they form annual growth rings. (orig.) [de

  6. Years of annual ring formation of trees and elements of minute amount

    International Nuclear Information System (INIS)

    Katayama, Yukio

    1988-01-01

    The structure of the trunks of trees is briefly explained, and the effect of environmental factors such as light, rain, soil, temperature and so on and the effect of environmental pollution are conceivable. The examples of the research on the quantitative determination of the elements of minute amount contained in the annual rings of trees and their use as the living things for environmental pollution index are shown, and the problems are considered. The concentration of manganese contained in annual rings may be used as environmental pollution index. It was pointed out that cadmium accumulated in annual rings had a strong correlation with the decrease of annual ring width. K-40 once taken in annual rings moved radially in connection with physical and physiological actions. The authors have examined the distribution of the elements of minute amount in the trunks, using Japanese cedar, white fir and oak as the specimens. For the quantitative analysis of the elements of minute amount, thermal neutron radioactivation analysis was used, which can analyze many elements simultaneously by nondestructive method. The elements of minute amount in the trunks of Japanese cedar, the difference of the distribution according to the kinds of trees, and the movement of elements within trunks are reported. The application of PIXE method to this analysis is considered. (Kako, I.)

  7. Determination of major elements in annual tree rings by acid extraction

    International Nuclear Information System (INIS)

    Belacy, N.; Abou EL-Nour, F.; Simpson, H.J.

    1991-01-01

    A method utilizing acid extraction of Na, K, Ca and Mg from the wood of annual growth rings of egyptian trees was executed. The method was applied on a Morus Alba tree located at Nile delta, northern of egypt. The acid extraction method includes the use of dilute nitric acid to extract the elements of the wood. The wood was soaked for one hour with continuous stirring at room temperature. Element contents of both leachant and ash of the extracted wood dissolved in 2N HNO 3 , were then estimated using an atomic absorption spectrophotometer. The method was optimized and led to an accurate determination of the elements in the wood of the examined tree rings. The results showed a difference in the level of these elements along the annual rings of the examined tree. The data obtained in this work can help in understanding the correlation between the concentration of these elements in the annual growth rings of the egyptian trees and the expected changes in the salinity of water of irrigation before and after the high dam project

  8. Determining the annual periodicity of growth rings in seven tree species of a tropical moist forest in Santa Cruz, Bolivia

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, L.; Villalba, R.; Pena-Claros, M.

    2012-07-01

    To determine the annual periodicity of growth rings in seven tree species from a tropical moist forest in Santa Cruz, Bolivia, a fire scar was used as a marker point to verify the annual nature of tree rings. The number of tree rings formed between the 1995 fire scar and the collection of the cross sections in 2002 was visually identified. The seven species showed annual growth rings. In most cases, boundaries between rings were marked by the presence of marginal parenchyma and wall-thick ed fibers formed at the end of the growing season. Growth lenses and false rings were recorded in some species. Tree rings can be carefully used in Santa Cruz forests to determine rates of growth. This information is crucial for defining forest management practices in tropical regions. (Author) 21 refs.

  9. Monthly paleostreamflow reconstruction from annual tree-ring chronologies

    Science.gov (United States)

    J. H. Stagge; D. E. Rosenberg; R. J. DeRose; T. M. Rittenour

    2018-01-01

    Paleoclimate reconstructions are increasingly used to characterize annual climate variability prior to the instrumental record, to improve estimates of climate extremes, and to provide a baseline for climate change projections. To date, paleoclimate records have seen limited engineering use to estimate hydrologic risks because water systems models and managers usually...

  10. Regional climate pattern during two millennia estimated from annual tree rings of Yaku cedar trees: a hint for solar variability?

    Science.gov (United States)

    Muraki, Yasushi; Mitsutani, Takumi; Shibata, Shoichi; Kuramata, Syuichi; Masuda, Kimiaki; Nagaya, Kentaro

    2015-02-01

    We analyzed trees that have survived on Yaku island (Yakushima) for 2,000 years. Quite surprisingly, the Fourier and wavelet analyses of the annual growth rate identified 2 cycles of periodicities of 11 and (24 ± 4) years during the Oort, Wolf, Spörer, Maunder, and Dalton minima. The 11-year periodicity originated from solar activity, while the (24 ± 4)-year periodicity may be related to the Pacific Decadal Oscillation (PDO). In particular, we have discovered an 11-year periodicity in the meteorological daylight-hour data from Yakushima in the month of June during 1938 to 2013 and a 24-year periodicity in July. The growth rate of the tree rings may be affected by the variation of the daylight hour.

  11. Annual tree rings in Piptadenia gonoacantha (Mart. J.F.Macbr. in a restoration experiment in the Atlantic Forest: potential for dendroecological research

    Directory of Open Access Journals (Sweden)

    Arno Fritz das Neves Brandes

    2016-01-01

    Full Text Available ABSTRACT The tree Piptadenia gonoachantha is widely used in forestry and in forest restoration projects, which require methods for evaluating tree growth. Long-term studies are necessary to determine patterns and detect changes in species growth rhythms. Tree ring analysis provides a precise method for determining age and documenting long-term growth trends in tropical tree species. The present study evaluated the periodicity of tree ring formation and radial growth dynamics of P. gonoachantha from a population of known age in the Poço das Antas Biological Reserve. Two radii from six trees were sampled using non-destructive methods. Tree rings were counted and measured to estimate age and to calculate diametric increment. All samples had 16 tree rings, which matched the known plantation age and confirmed the annual formation of rings. The individuals sampled had a mean annual diametric increment of 9.5 mm / year. Results showed a trend towards decreasing growth rate with increasing age. Individuals of P. gonoachantha in Ombrophilous Dense Forest produce annual tree rings, which holds potential for future dendroecological studies.

  12. A simple, single-substrate model to interpret intra-annual stable isotope signals in tree-ring cellulose

    Science.gov (United States)

    Ogée, J.; Barbour, M. M.; Wingate, L.; Bert, D.; Bosc, A.; Stievenard, M.; Lambrot, C.; Pierre, M.; Bariac, T.; Dewar, R. C.

    2009-04-01

    High-resolution intra-annual measurements of the carbon and oxygen stable isotope composition of cellulose in annual tree rings (δ13Ccellulose and δ18Ocellulose, respectively) reveal well-defined seasonal patterns that could contain valuable records of past climate and tree function. Interpreting these signals is nonetheless complex because they not only record the signature of current assimilates, but also depend on carbon allocation dynamics within the trees. Here, we present a simple, single-substrate model for wood growth containing only 12 main parameters. The model is used to interpret an isotopic intra-annual chronology collected in an even-aged maritime pine plantation growing in the South-West of France, where climate, soil and flux variables were also monitored. The empirical δ13Ccellulose and δ18Ocellulose exhibit dynamic seasonal patterns, with clear differences between years and individuals, that are mostly captured by the model. In particular, the amplitude of both signals is reproduced satisfactorily as well as the sharp 18O enrichment at the beginning of 1997 and the less pronounced 13C and 18O depletion observed at the end of the latewood. Our results suggest that the single-substrate hypothesis is a good approximation for tree ring studies on Pinus pinaster, at least for the environmental conditions covered by this study. A sensitivity analysis revealed that, in the early wood, the model was particularly sensitive to the date when cell wall thickening begins (twt). We therefore propose to use the model to reconstruct time series of twt and explore how climate influences this key parameter of xylogenesis.

  13. TREE SELECTING AND TREE RING MEASURING IN DENDROCHRONOLOGICAL INVESTIGATIONS

    Directory of Open Access Journals (Sweden)

    Sefa Akbulut

    2004-04-01

    Full Text Available Dendrochronology is a method of dating which makes use of the annual nature of tree growth. Dendrochronology may be divided into a number of subfields, each of which covers one or more aspects of the use of tree ring data: dendroclimatology, dendrogeomorphology, dendrohydrology, dendroecology, dendroarchaelogy, and dendrogylaciology. Basic of all form the analysis of the tree rings. The wood or tree rings can aid to dating past events about climatology, ecology, geology, hydrology. Dendrochronological studies are conducted either on increment cores or on discs. It may be seen abnormalities on tree rings during the measurement like that false rings, missing rings, reaction wood. Like that situation, increment cores must be extracted from four different sides of each tree and be studied as more as on tree.

  14. The suitability of annual tree growth rings as environmental archives: Evidence from Sr, Nd, Pb and Ca isotopes in spruce growth rings from the Strengbach watershed

    Science.gov (United States)

    Stille, Peter; Schmitt, Anne-Désirée; Labolle, François; Pierret, Marie-Claire; Gangloff, Sophie; Cobert, Florian; Lucot, Eric; Guéguen, Florence; Brioschi, Laure; Steinmann, Marc; Chabaux, François

    2012-05-01

    The combination of the Sr, Nd and Pb isotope systems, recognized as tracers of sources, with the Ca isotope system, known to reveal biology-related fractionations, allowed us to test the reliability of spruce (Picea abies) growth rings as environmental archives through time (from 1916 to 1983) in a forest ecosystem affected by acid atmospheric deposition. Sr and Pb isotopes have already been applied in former tree-ring studies, whereas the suitability of Nd and Ca isotope systems is checked in the present article. Our Sr and Nd isotope data indicate an evolution in the cation origin with a geogenic origin for the oldest rings and an atmospheric origin for the youngest rings. Ca isotopes show, for their part, an isotopic homogeneity which could be linked to the very low weathering flux of Ca. Since this flux is weak the spruces' root systems have pumped the Ca mainly from the organic matter-rich top-soil over the past century. In contrast, the annual growth rings studied are not reliable and suitable archives of past Pb pollution.

  15. Tree rings and radiocarbon calibration

    International Nuclear Information System (INIS)

    Barbetti, M.

    1999-01-01

    Only a few kinds of trees in Australia and Southeast Asia are known to have growth rings that are both distinct and annual. Those that do are therefore extremely important to climatic and isotope studies. In western Tasmania, extensive work with Huon pine (Lagarostrobos franklinii) has shown that many living trees are more than 1,000 years old, and that their ring widths are sensitive to temperature, rainfall and cloud cover (Buckley et al. 1997). At the Stanley River there is a forest of living (and recently felled) trees which we have sampled and measured. There are also thousands of subfossil Huon pine logs, buried at depths less than 5 metres in an area of floodplain extending over a distance of more than a kilometre with a width of tens of metres. Some of these logs have been buried for 50,000 years or more, but most of them belong to the period between 15,000 years and the present. In previous expeditions in the 1980s and 1990s, we excavated and sampled about 350 logs (Barbetti et al. 1995; Nanson et al. 1995). By measuring the ring-width patterns, and matching them between logs and living trees, we have constructed a tree-ring dated chronology from 571 BC to AD 1992. We have also built a 4254-ring floating chronology (placed by radiocarbon at ca. 3580 to 7830 years ago), and an earlier 1268-ring chronology (ca. 7,580 to 8,850 years ago). There are many individuals, or pairs of logs which match and together span several centuries, at 9,000 years ago and beyond

  16. Estimating long-term statistics for annual precipitation for six regions of the United States from tree-ring data

    International Nuclear Information System (INIS)

    Fritts, H.C.; DeWitt, E.; Gordon, G.A.; Hunt, J.H.; Lofgren, G.R.

    1979-12-01

    Spatial anomalies of seasonal precipitation for the United States and southwestern Canada have been reconstructed from 1602 through 1961 using dendrochronological and multivariate techniques on 65 arid-site tree-ring chronologies from western North America. Seasonal reconstructions are averaged to obtain mean annual precipitation values for six regions of importance to the Nuclear Regulatory Commission (NRC) Nuclear Waste Management Program (NWMP). Statistics calculated from the regionally averaged annual values for 25-year and longer intervals show annual precipitation in the seventeenth through nineteenth centuries to be lower than in the twentieth century for three regions in the American Southwest and higher for one region in the Northwest and two regions in the East. The variability of precipitation generally was higher in the past three centuries than in the present century. Twenty-five-year intervals with noteworthy statistics are identified and important results are summarized and tabulated for use in the hydrologic modeling of the NWMP. Additional research is recommended to incorporate temperature and precipitation into a single hydrologic parameter

  17. Tree Rings: Timekeepers of the Past.

    Science.gov (United States)

    Phipps, R. L.; McGowan, J.

    One of a series of general interest publications on science issues, this booklet describes the uses of tree rings in historical and biological recordkeeping. Separate sections cover the following topics: dating of tree rings, dating with tree rings, tree ring formation, tree ring identification, sample collections, tree ring cross dating, tree…

  18. Carbon-14 in tree rings

    International Nuclear Information System (INIS)

    Cain, W.F.; Suess, H.E.

    1976-01-01

    In order to investigate how reliably the carbon 14 content of tree rings reflects that of atmospheric carbon dioxide, two types of determinations were carried out: (1) carbon 14 determinations in annual rings from the beginning of this century until 1974 and (2) carbon 14 determinations in synchronous wood from the North American bristlecone pine and from European oak trees, dendrochronologically dated to have grown in the third and fourth century B.C. The first series of measurements showed that bomb-produced radiocarbon was incorporated in wood at a time when it was converted from sapwood to heartwood, whenever radiocarbon from bomb testing was present in the atmosphere. The second series showed that wood more than 2000 years old and grown on two different continents at different altitudes had, within the limits of experimental error, the same radiocarbon content. This work and other experimental evidence, obtained in part by other laboratories, show that tree rings reflect the average radiocarbon content of global atmospheric carbon dioxide accurately within several parts per mil. In rare cases, deviations of up to 10 parts per thousand may be possible. This means that a typical single radiocarbon date for wood or charcoal possesses an intrinsic uncertainty (viz., an estimated ''one-sigma error'' in addition to all the other errors) of the order of +-50 years. This intrinsic uncertainty is independent of the absolute age of the sample. More accurate dates can, in principle, be obtained by the so-called method of ''wiggle matching.''

  19. Distribution of ^<90>Sr and ^<137>Cs in Annual Tree Rings of Japanese Cedar, Cryptomeria Japonica D.Don.

    OpenAIRE

    千木良, みどり; 斎藤, 裕子; 木村, 幹; MIDORI, CHIGIRA; YUKO, SAITO; KAN, KIMURA; 青山学院大学理工学部; 青山学院大学理工学部; 青山学院大学理工学部; Department of Chemistry, College of Science and Engineering, Aoyama Gakuin University; Department of Chemistry, College of Science and Engineering, Aoyama Gakuin University; Department of Chemistry, College of Science and Engineering, Aoyama Gakuin University

    1988-01-01

    The contents of ^Sr and ^Cs in two samples of Japanese cedar from Takao and Tsukui districts were determined in tree rings cut into segments representing steps of 5 years of growth. ^Sr in both cedar samples and ^Cs in the Tsukui cedar sample were determined after ashing and chemical isolation, while ^Cs in the Takao sample was directly determined from the sample ash. The distribution of ^Sr fallout in tree rings suggests that ^Sr had given a rather direct effect and showed no significant tra...

  20. Distribution of 90Sr and 137Cs in annual tree rings of Japanese cedar, Cryptomeria Japonica D. Don

    International Nuclear Information System (INIS)

    Chigira, Midori; Saito, Yuko; Kimura, Kan

    1988-01-01

    The contents of 90 Sr and 137 Cs in two samples of Japanese cedar from Takao and Tsukui districts were determined in tree rings cut into segments representing steps of 5 years of growth. 90 Sr in both cedar samples and 137 Cs in the Tsukui cedar sample were determined after ashing and chemical isolation, while 137 Cs in the Takao sample was directly determined from the sample ash. The distribution of 90 Sr fallout in tree rings suggests that 90 Sr had given a rather direct effect and showed no significant translocation from sapwood to heartwood, whereas 137 Cs tends to concentrate in heartwood irrespective of the effect of the fallout. Average contents of 90 Sr and 137 Cs were 22 and 9.4 pCi/kg in the Takao sample (9.61 kg air dried) and were 23 and 12 in the Tsukui (4.71 kg air dried) in 1982. (author)

  1. Lateglacial environmental variability from Swiss tree rings

    DEFF Research Database (Denmark)

    Schaub, Matthias; Büntgen, Ulf; Kaiser, Klaus Felix

    2008-01-01

    Evidence of annually resolved environmental variations during the Allerød interstadial is presented using 81 fossil Scots pine tree-ring series from Gaenziloo and Landikon, near Zurich, Switzerland. The absolute age of the trees ranges between 11,920 and 10,610 14C BP, which was determined by wig...... and the gray-scale varve record from the Cariaco basin. Even though the amplitudes are not yet fully understood, similarities on decadal-to-centennial scales are apparent....

  2. Laser ablation-combustion-GC-IRMS--a new method for online analysis of intra-annual variation of delta13C in tree rings.

    Science.gov (United States)

    Schulze, Brigit; Wirth, Christian; Linke, Petra; Brand, Willi A; Kuhlmann, Iris; Horna, Viviana; Schulze, Ernst-Detlef

    2004-11-01

    We present a new, rapid method for high-resolution online determination of delta13C in tree rings, combining laser ablation (LA), combustion (C), gas chromatography (GC) and isotope ratio mass spectrometry (IRMS) (LA-C-GC-IRMS). Sample material was extracted every 6 min with a UV-laser from a tree core, leaving 40-microm-wide holes. Ablated wood dust was combusted to CO2 at 700 degrees C, separated from other gases on a GC column and injected into an isotope ratio mass spectrometer after removal of water vapor. The measurements were calibrated against an internal and an external standard. The tree core remained intact and could be used for subsequent dendrochronological and dendrochemical analyses. Cores from two Scots pine trees (Pinus sylvestris spp. sibirica Lebed.) from central Siberia were sampled. Inter- and intra-annual patterns of delta13C in whole-wood and lignin-extracted cores were indistinguishable apart from a constant offset, suggesting that lignin extraction is unnecessary for our method. Comparison with the conventional method (microtome slicing, elemental analysis and IRMS) indicated high accuracy of the LA-C-GC-IRMS measurements. Patterns of delta13C along three parallel ablation lines on the same core showed high congruence. A conservative estimate of the precision was +/- 0.24 per thousand. Isotopic patterns of the two Scots pine trees were broadly similar, indicating a signal related to the forest stand's climate history. The maximum variation in delta13C over 22 years was about 5 per thousand, ranging from -27 to -22.3 per thousand. The most obvious pattern was a sharp decline in delta13C during latewood formation and a rapid increase with spring early growth. We conclude that the LA-C-GC-IRMS method will be useful in elucidating short-term climate effects on the delta13C signal in tree rings.

  3. International Tree Ring Data Bank (ITRDB)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tree ring data from the International Tree Ring Data Bank and World Data Center for Paleoclimatology archives. Data include raw treering measurements (most are...

  4. Study of radial distribution of 239,240Pu and 90Sr in annual tree rings and trunk bark of a 103 years old Norway spruce at four different heights above ground

    International Nuclear Information System (INIS)

    Holgye, Z.; Schlesingerova, E.

    2016-01-01

    Radial distribution of 239,240 Pu and 90 Sr originating from atmospheric nuclear tests in tree rings and trunk bark at heights of 1.3, 10, 18 and 22 m above ground was studied. 239,240 Pu activity concentrations in air dried tree ring samples (each containing 10 annual rings) at all heights were under detection limit of the used method. 90 Sr activity concentrations in tree ring samples ranged from 0.54 to 2.81 Bq kg -1 . 239,240 Pu and 90 Sr were present in the trunk bark. The paper presents data for 239,240 Pu and 90 Sr aggregated transfer factors to tree trunk. (author)

  5. High-precision analysis on annual variations of heavy metals, lead isotopes and rare earth elements in mangrove tree rings by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Yu Kefu; Kamber, Balz S.; Lawrence, Michael G.; Greig, Alan; Zhao Jianxin

    2007-01-01

    Annual variations from 1982 to 1999 of a wide range of trace elements and reconnaissance Pb isotopes ( 207 Pb/ 206 Pb and 208 Pb/ 206 Pb) were analyzed by solution ICP-MS on digested ash from mangrove Rhizophora apiculata, obtained from Leizhou Peninsula, along northern coast of South China Sea. The concentrations of the majority of elements show a weak declining trend with growth from 1982 to 1999, punctuated by several high concentration spikes. The declining trends are positively correlated with ring width and negatively correlated with inferred water-use efficiency, suggesting a physiological control over metal-uptake in this species. The episodic metal concentration-peaks cannot be interpreted with lateral movement or growth activities and appear to be related to environmental pollution events. Pb isotope ratios for most samples plot along the 'Chinese Pb line' and clearly document the importance of gasoline Pb as a source of contaminant. Shale-normalised REE + Y patterns are relatively flat and consistent across the growth period, with all patterns showing a positive Ce anomaly and elevated Y/Ho ratio. The positive Ce anomaly is observed regardless of the choice of normaliser, in contrast to previously reported REE patterns for terrestrial and marine plants. This pilot study of trace element, REE + Y and Pb isotope distribution in mangrove tree rings indicates the potential use of mangroves as monitors of historical environmental change

  6. Plutonium in tree rings from France and Japan

    International Nuclear Information System (INIS)

    Garrec, J.-P.; Suzuki, T.; Mahara, Y.; Santry, D.C.; Miyahara, S.; Sugahara, M.; Zheng, J.; Kudo, A.

    1995-01-01

    Plutonium, along with other radionuclide concentrations, was measured in evergreen tree rings from two different locations. This was used as an information source for the past two centuries. Tree rings are a product of annual layers and thus chronological information is clearly visible. Three trees were harvested in 1988-1990: a French white fir (137 years old) and a spruce tree (177 years old) from the France-Germany border near Nancy, France and a sugi (78 years old) from Nagasaki, Japan. The highest 239 + 240 Pu concentration of 30.0 mBq/kg of dry wood was obtained from the tree rings from Nagasaki, located at the centre of the local fallout of the Pu A-bomb detonated in 1945. This concentration peak was, however, observed in tree rings of 1965-67. The concentration was only 2.9 mBq/kg for the tree rings of 1944-46. The contribution of the local fallout on the surface soils from the A-bomb was 181 mBq/cm 2 at the harvested area of the tree, while the contribution of global fallout by many weapons testing was 5.9 mBq/cm 2 (or 3.3% total fallout in the region). The reason for the over 20 year time lag of 239 + 240 Pu uptake by the tree rings is unknown because many factors influence the routes of Pu into the tree rings. Also the chemical form of Pu in surface soils may have been changed by the surrounding environment. The highest concentration in the tree rings from France was 9.4 mBq/kg which is about 31% of Nagasaki 239 + 240 Pu concentration. (author)

  7. Tree-ring variation in teak (Tectona grandis L.) from Allapalli ...

    Indian Academy of Sciences (India)

    region. Tree-ring variations were most correlated positively with PDSI during different seasons ... significant role in the development of annual growth rings. ..... (which is an integration of precipitation and mean ..... This shows that the network of.

  8. Tritium concentrations in tree ring cellulose

    International Nuclear Information System (INIS)

    Kaji, Toshio; Momoshima, Noriyuki; Takashima, Yoshimasa.

    1989-01-01

    Measurements of tritium (tissue bound tritium; TBT) concentration in tree rings are presented and discussed. Such measurement is expected to provide a useful means of estimating the tritium level in the environment in the past. The concentration of tritium bound in the tissue (TBT) in a tree ring considered to reflect the environmental tritium level in the area at the time of the formation of the ring, while the concentration of tritium in the free water in the tissue represents the current environmental tritium level. First, tritium concentration in tree ring cellulose sampled from a cedar tree grown in a typical environment in Fukuoka Prefecture is compared with the tritium concentration in precipitation in Tokyo. Results show that the year-to-year variations in the tritium concentration in the tree rings agree well with those in precipitation. The maximum concentration, which occurred in 1963, is attibuted to atmospheric nuclear testing which was performed frequently during the 1961 - 1963 period. Measurement is also made of the tritium concentration in tree ring cellulose sampled from a pine tree grown near the Isotope Center of Kyushu University (Fukuoka). Results indicate that the background level is higher probably due to the release of tritium from the facilities around the pine tree. Thus, measurement of tritium in tree ring cellulose clearly shows the year-to-year variation in the tritium concentration in the atmosphere. (N.K.)

  9. Impact of traffic on δ15N, δ13C and δ18O of needles and annual tree rings of Norway spruce (Picea abies L.

    Directory of Open Access Journals (Sweden)

    Guerrieri MR

    2006-01-01

    Full Text Available Increase of nitrogen depositions, as oxidized (NOx and reduced (NHx compounds, has important implications on ecosystem nitrogen cycle. NOx comes predominantly from fossil fuel combustion in car engines and industrial processes, while agricultural activities (cattle farming, fertilizations are the main sources for NHx emissions. Such fertilisations could stimulate growth and, therefore, productivity of forests, especially in temperate forests, where nitrogen is a limiting factor. On the other hand an excess of nitrogen can lead to an acidification of the soil and have a negative impact on the microbial fauna and structure of plants. NOx and NHx depositions can be separated with the help of stable isotopes with different 15N-values reported for NOx originating from combustion sources. Consequently it was observed that the nitrogen isotopic composition of the vegetation reflects the isotopic signature of nitrogen sources. Our preliminary results on needles of Norway spruce trees exposed to NOx emissions along a transect perpendicular to a highway close to Faido and Brittnau show a clear isotopic enrichment in 15N in trees growing closer to traffic pollution, indicating an uptake of atmospheric nitrogen by stomatal pathway. Carbon and oxygen isotopic composition measured in tree rings reveals the physiological response in plants. Trees more exposed to air pollution from traffic show an increase in δ13C and δ18O in tree rings, since mid sixties next to Erstfeld. This could mean a higher photosynthetic activity, enhanced by NOx traffic emissions, under low or not changed stomatal conductance. Our results confirm that stable isotopes of carbon, oxygen and nitrogen measured in needles and tree rings represent an important tool to monitor the impact of NOx load on tree physiology.

  10. Radioecological investigations on tree rings of spruce

    International Nuclear Information System (INIS)

    Haas, G.; Mueller, A.

    1995-01-01

    Tree ring analysis contributes essentially to the explanation of physiological and element-specific transport phenomena in trees. After the accident in Chernobyl the behaviour of Cs-134 and Cs-137 in trees is most informative for the prediction of the future development of the distribution of these elements. In this study the uptake and the long term behaviour of Cs-134, Cs-137, Pb-210, Ra-226, Ra-228, K-40, Th-228, Th-230, Th-232, U-234 and U-238 in tree rings of spruce are examined by α- and γ-spectrometry. All samples are dried at 105C and ashed at 450C in a muffle furnace. The distributions found in the tree rings vary for different radionuclides. A soil profile from the spruce stand provides additional information

  11. Nonannual tree rings in a climate-sensitive Prioria copaifera chronology in the Atrato River, Colombia.

    Science.gov (United States)

    Herrera-Ramirez, David; Andreu-Hayles, Laia; Del Valle, Jorge I; Santos, Guaciara M; Gonzalez, Paula L M

    2017-08-01

    In temperate climates, tree growth dormancy usually ensures the annual nature of tree rings, but in tropical environments, determination of annual periodicity can be more complex. The purposes of the work are as follows: (1) to generate a reliable tree-ring width chronology for Prioria copaifera Griseb. (Leguminoceae), a tropical tree species dwelling in the Atrato River floodplains, Colombia; (2) to assess the climate signal recorded by the tree-ring records; and (3) to validate the annual periodicity of the tree rings using independent methods. We used standard dendrochronological procedures to generate the P. copaifera tree-ring chronology. We used Pearson correlations to evaluate the relationship of the chronology with the meteorological records, climate regional indices, and gridded precipitation/sea surface temperature products. We also evaluated 24 high-precision 14 C measurements spread over a range of preselected tree rings, with assigned calendar years by dendrochronological techniques, before and after the bomb spike in order to validate the annual nature of the tree rings. The tree-ring width chronology was statistically reliable, and it correlated significantly with local records of annual and October-December (OND) streamflow and precipitation across the upper river watershed (positive), and OND temperature (negative). It was also significantly related to the Oceanic Niño Index, Pacific Decadal Oscillation, and the Southern Oscillation Index, as well as sea surface temperatures over the Caribbean and the Pacific region. However, 14 C high-precision measurements over the tree rings demonstrated offsets of up to 40 years that indicate that P. copaifera can produce more than one ring in certain years. Results derived from the strongest climate-growth relationship during the most recent years of the record suggest that the climatic signal reported may be due to the presence of annual rings in some of those trees in recent years. Our study alerts about

  12. Possibilities of climate reconstruction in the Holocene using δ13C and δ2H values from annual tree rings on the basis of climate chamber experiments and studies on present-day organisms

    International Nuclear Information System (INIS)

    Mayr, C.

    2002-01-01

    This study deals with the climatic information content of 2 H and 13 C levels in annual tree rings and plant material. The influence of variations in air temperature, relative humidity and water availability on stable isotope ratios in three different C 3 plant species (Brassica oleracea, Eucalyptus globulus, Vicia faba) was studied in climate chamber experiments. Furthermore, calibration studies using δ 13 C and δ 2 H time series from Southern German spruce (Picea abies) from two stands (Schussbach, Klosterreichenbach) were performed. Correlations with meteorological data from a nearby meteorological station prove stable isotope ratios to be dependent on weather conditions in the summer months (June through August). Using the δ 13 C ''response surfaces'' obtained from these experiments as well as correlations from long gridbox precipitation series it was shown that for the climate mode under study the δ 13 C values largely reflect water availability to trees, which is greatly influenced by summer precipitation, especially at the more arid of the two sites. The results of the climate chamber experiments also suggest that the spruce δ 2 H values largely reflect the isotope variation in soil water and hence the δ 2 H fluctuations in summer precipitation. The study closes with a discussion of methodological approaches to creating long isotope series from annual tree rings of subfossil oak trees

  13. Relating tree growth to rainfall in Bolivian rain forests: a test for six species using tree ring analysis.

    Science.gov (United States)

    Brienen, Roel J W; Zuidema, Pieter A

    2005-11-01

    Many tropical regions show one distinct dry season. Often, this seasonality induces cambial dormancy of trees, particularly if these belong to deciduous species. This will often lead to the formation of annual rings. The aim of this study was to determine whether tree species in the Bolivian Amazon region form annual rings and to study the influence of the total amount and seasonal distribution of rainfall on diameter growth. Ring widths were measured on stem discs of a total of 154 trees belonging to six rain forest species. By correlating ring width and monthly rainfall data we proved the annual character of the tree rings for four of our study species. For two other species the annual character was proved by counting rings on trees of known age and by radiocarbon dating. The results of the climate-growth analysis show a positive relationship between tree growth and rainfall in certain periods of the year, indicating that rainfall plays a major role in tree growth. Three species showed a strong relationship with rainfall at the beginning of the rainy season, while one species is most sensitive to the rainfall at the end of the previous growing season. These results clearly demonstrate that tree ring analysis can be successfully applied in the tropics and that it is a promising method for various research disciplines.

  14. Extreme Drought Events Revealed in Amazon Tree Ring Records

    Science.gov (United States)

    Jenkins, H. S.; Baker, P. A.; Guilderson, T. P.

    2010-12-01

    The Amazon basin is a center of deep atmospheric convection and thus acts as a major engine for global hydrologic circulation. Yet despite its significance, a full understanding of Amazon rainfall variability remains elusive due to a poor historical record of climate. Temperate tree rings have been used extensively to reconstruct climate over the last thousand years, however less attention has been given to the application of dendrochronology in tropical regions, in large part due to a lower frequency of tree species known to produce annual rings. Here we present a tree ring record of drought extremes from the Madre de Dios region of southeastern Peru over the last 190 years. We confirm that tree ring growth in species Cedrela odorata is annual and show it to be well correlated with wet season precipitation. This correlation is used to identify extreme dry (and wet) events that have occurred in the past. We focus on drought events identified in the record as drought frequency is expected to increase over the Amazon in a warming climate. The Cedrela chronology records historic Amazon droughts of the 20th century previously identified in the literature and extends the record of drought for this region to the year 1816. Our analysis shows that there has been an increase in the frequency of extreme drought (mean recurrence interval = 5-6 years) since the turn of the 20th century and both Atlantic and Pacific sea surface temperature (SST) forcing mechanisms are implicated.

  15. Visualizing Individual Tree Differences in Tree-Ring Studies

    Directory of Open Access Journals (Sweden)

    Mario Trouillier

    2018-04-01

    Full Text Available Averaging tree-ring measurements from multiple individuals is one of the most common procedures in dendrochronology. It serves to filter out noise from individual differences between trees, such as competition, height, and micro-site effects, which ideally results in a site chronology sensitive to regional scale factors such as climate. However, the climate sensitivity of individual trees can be modulated by factors like competition, height, and nitrogen deposition, calling attention to whether average chronologies adequately assess climatic growth-control. In this study, we demonstrate four simple but effective methods to visually assess differences between individual trees. Using individual tree climate-correlations we: (1 employed jitter plots with superimposed metadata to assess potential causes for these differences; (2 plotted the frequency distributions of climate correlations over time as heat maps; (3 mapped the spatial distribution of climate sensitivity over time to assess spatio-temporal dynamics; and (4 used t-distributed Stochastic Neighborhood Embedding (t-SNE to assess which trees were generally more similar in terms of their tree-ring pattern and their correlation with climate variables. This suite of exploratory methods can indicate if individuals in tree-ring datasets respond differently to climate variability, and therefore, should not solely be explored with climate correlations of the mean population chronology.

  16. Use of Tritium Accelerator Mass Spectrometry for Tree Ring Analysis

    Science.gov (United States)

    LOVE, ADAM H.; HUNT, JAMES R.; ROBERTS, MARK L.; SOUTHON, JOHN R.; CHIARAPPA - ZUCCA, MARINA L.; DINGLEY, KAREN H.

    2010-01-01

    Public concerns over the health effects associated with low-level and long-term exposure to tritium released from industrial point sources have generated the demand for better methods to evaluate historical tritium exposure levels for these communities. The cellulose of trees accurately reflects the tritium concentration in the source water and may contain the only historical record of tritium exposure. The tritium activity in the annual rings of a tree was measured using accelerator mass spectrometry to reconstruct historical annual averages of tritium exposure. Milligram-sized samples of the annual tree rings from a Tamarix located at the Nevada Test Site are used for validation of this methodology. The salt cedar was chosen since it had a single source of tritiated water that was well-characterized as it varied over time. The decay-corrected tritium activity of the water in which the salt cedar grew closely agrees with the organically bound tritium activity in its annual rings. This demonstrates that the milligram-sized samples used in tritium accelerator mass spectrometry are suited for reconstructing anthropogenic tritium levels in the environment. PMID:12144257

  17. Properties of tree rings in LSST sensors

    International Nuclear Information System (INIS)

    Park, H.Y.; Tsybychev, D.; Nomerotski, A.

    2017-01-01

    Images of uniformly illuminated sensors for the Large Synoptic Survey Telescope have circular periodic patterns with an appearance similar to tree rings. These patterns are caused by circularly symmetric variations of the dopant concentration in the monocrystal silicon boule induced by the manufacturing process. Non-uniform charge density results in the parasitic electric field inside the silicon sensor, which may distort shapes of astronomical sources. In this study we analyzed data from fifteen LSST sensors produced by ITL to determine the main parameters of the tree rings: amplitude and period, and also variability across the sensors tested at Brookhaven National Laboratory. Tree ring pattern has a weak dependence on the wavelength. However the ring amplitude gets smaller as wavelength gets longer, since longer wavelengths penetrate deeper into the silicon. Tree ring amplitude gets larger as it gets closer to the outer part of the wafer, from 0.1 to 1.0%, indicating that the resistivity variation is larger for larger radii.

  18. A tree-ring perspective on the terrestrial carbon cycle

    International Nuclear Information System (INIS)

    Babst, F.; Alexander, M.R.; Szejner, P.; Trouet, V.; Alexander, M.R.; Moore, D.J.P.; Bouriaud, O.; Klesse, S.; Frank, D.; Roden, J.; Ciais, P.; Poulter, B.

    2014-01-01

    Tree-ring records can provide valuable information to advance our understanding of contemporary terrestrial carbon cycling and to reconstruct key metrics in the decades preceding monitoring data. The growing use of tree rings in carbon-cycle research is being facilitated by increasing recognition of reciprocal benefits among research communities. Yet, basic questions persist regarding what tree rings represent at the ecosystem level, how to optimally integrate them with other data streams, and what related challenges need to be overcome. It is also apparent that considerable unexplored potential exists for tree rings to refine assessments of terrestrial carbon cycling across a range of temporal and spatial domains. Here, we summarize recent advances and highlight promising paths of investigation with respect to (1) growth phenology, (2) forest productivity trends and variability, (3) CO 2 fertilization and water-use efficiency, (4) forest disturbances, and (5) comparisons between observational and computational forest productivity estimates. We encourage the integration of tree-ring data: with eddy-covariance measurements to investigate carbon allocation patterns and water-use efficiency; with remotely sensed observations to distinguish the timing of cambial growth and leaf phenology; and with forest inventories to develop continuous, annually resolved and long-term carbon budgets. In addition, we note the potential of tree-ring records and derivatives thereof to help evaluate the performance of earth system models regarding the simulated magnitude and dynamics of forest carbon uptake, and inform these models about growth responses to (non-)climatic drivers. Such efforts are expected to improve our understanding of forest carbon cycling and place current developments into a long-term perspective. (authors)

  19. Olive tree-ring problematic dating: a comparative analysis on Santorini (Greece.

    Directory of Open Access Journals (Sweden)

    Paolo Cherubini

    Full Text Available Olive trees are a classic component of Mediterranean environments and some of them are known historically to be very old. In order to evaluate the possibility to use olive tree-rings for dendrochronology, we examined by various methods the reliability of olive tree-rings identification. Dendrochronological analyses of olive trees growing on the Aegean island Santorini (Greece show that the determination of the number of tree-rings is impossible because of intra-annual wood density fluctuations, variability in tree-ring boundary structure, and restriction of its cambial activity to shifting sectors of the circumference, causing the tree-ring sequences along radii of the same cross section to differ.

  20. Olive tree-ring problematic dating: a comparative analysis on Santorini (Greece).

    Science.gov (United States)

    Cherubini, Paolo; Humbel, Turi; Beeckman, Hans; Gärtner, Holger; Mannes, David; Pearson, Charlotte; Schoch, Werner; Tognetti, Roberto; Lev-Yadun, Simcha

    2013-01-01

    Olive trees are a classic component of Mediterranean environments and some of them are known historically to be very old. In order to evaluate the possibility to use olive tree-rings for dendrochronology, we examined by various methods the reliability of olive tree-rings identification. Dendrochronological analyses of olive trees growing on the Aegean island Santorini (Greece) show that the determination of the number of tree-rings is impossible because of intra-annual wood density fluctuations, variability in tree-ring boundary structure, and restriction of its cambial activity to shifting sectors of the circumference, causing the tree-ring sequences along radii of the same cross section to differ.

  1. Dating floodplain sediments using tree-ring response to burial

    Science.gov (United States)

    Friedman, J.M.; Vincent, K.R.; Shafroth, P.B.

    2005-01-01

    Floodplain sediments can be dated precisely based on the change in anatomy of tree rings upon burial. When a stem of tamarisk (Tamarix ramosissima) or sandbar willow (Salix exigua) is buried, subsequent annual rings in the buried section resemble the rings of roots: rings become narrower, vessels within the rings become larger, and transitions between rings become less distinct. We combined observations of these changes with tree-ring counts to determine the year of deposition of sedimentary beds exposed in a 150-m-long trench across the floodplain of the Rio Puerco, a rapidly filling arroyo in New Mexico. This method reliably dated most beds thicker than about 30 cm to within a year of deposition. Floodplain aggradation rates varied dramatically through time and space. Sediment deposition was mostly limited to brief overbank flows occurring every few years. The most rapid deposition occurred on channel-margin levees, which migrated laterally during channel narrowing. At the decadal timescale, the cross-section-average sediment deposition rate was steady, but there was a shift in the spatial pattern of deposition in the 1980s. From 1936 to 1986, sediment deposition occurred by channel narrowing, with little change in elevation of the thalweg. After 1986 sediment deposition occurred by vertical aggradation. From 1936 to 2000 about 27 per cent of the arroyo cross-section filled with sediment. The rate of filling from 1962 to 2000 was 0·8 vertical m/decade or 85 m2/decade.

  2. An intensive tree-ring experience

    NARCIS (Netherlands)

    Sánchez-Salguero, Raúl; Hevia, Andrea; Camarero, J.J.; Treydte, Kerstin; Frank, Dave; Crivellaro, Alan; Domínguez-Delmás, Marta; Hellman, Lena; Kaczka, Ryszard J.; Kaye, Margot; Akhmetzyanov, Linar; Ashiq, Muhammad Waseem; Bhuyan, Upasana; Bondarenko, Olesia; Camisón, Álvaro; Camps, Sien; García, Vicenta Constante; Vaz, Filipe Costa; Gavrila, Ionela G.; Gulbranson, Erik; Huhtamaa, Heli; Janecka, Karolina; Jeffers, Darren; Jochner, Matthias; Koutecký, Tomáš; Lamrani-Alaoui, Mostafa; Lebreton-Anberrée, Julie; Seijo, María Martín; Matulewski, Pawel; Metslaid, Sandra; Miron, Sergiu; Morrisey, Robert; Opdebeeck, Jorgen; Ovchinnikov, Svyatoslav; Peters, Richard; Petritan, Any M.; Popkova, Margarita; Rehorkova, Stepanka; Ariza, María O.R.; Sánchez-Miranda, Ángela; Linden, Van der Marjolein; Vannoppen, Astrid; Volařík, Daniel

    2017-01-01

    The European Dendroecologial Fieldweek (EDF) provides an intensive learning experience in tree-ring research that challenges any participant to explore new multidisciplinary dendro-sciences approaches within the context of field and laboratory settings. Here we present the 25th EDF, held in

  3. Cottonwood Tree Rings and Climate in Western North America

    Science.gov (United States)

    Friedman, J. M.; Edmondson, J.; Griffin, E. R.; Meko, D. M.; Merigliano, M. F.; Scott, J. A.; Scott, M. L.; Touchan, R.

    2012-12-01

    In dry landscapes of interior western USA, cottonwood (Populus spp.) seedling establishment often occurs only close to river channels after floods. Where winter is sufficiently cold, cottonwoods also have distinct annual rings and can live up to 370 years, allowing us to reconstruct the long-term history of river flows and channel locations. We have analyzed the annual rate of cottonwood establishment along streams in Montana, Wyoming, Colorado, North Dakota and Idaho. Because the trees germinate next to the river, establishment rates are strongly correlated with the rate of channel migration driven by floods. Along large rivers dominated by snowmelt from the mountains, interannual variation in peak flows and cottonwood establishment is small, and century-scale variation driven by climate change is apparent. The upper Snake, Yellowstone and Green rivers all show a strong decrease in cottonwood establishment beginning in the late 1800s and continuing to the present, indicating a decrease in peak flows prior to flow regulation by large dams. This is consistent with published tree-ring studies of montane conifers showing decreases in snowpack at the same time scale. In contrast, beginning in the late 1800s cottonwood ring widths along the Little Missouri River, North Dakota show an increase in annual growth that continues into the present. Because annual growth is strongly correlated with April-July flows (r=0.69) the ring-width data suggest an increase in April-July flows at the same time tree establishment dates suggest a decrease in peak flows. These results may be reconciled by the hypothesis that increases in low temperatures have decreased snowpack while lengthening the growing season.

  4. Interdecadal modulation of the relationship between ENSO, IPO and precipitation: insights from tree rings in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, Ingo [School of Resources, Environment and Society, Australian National University, Canberra, ACT (Australia); Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Climate Dynamics and Landscape Evolution, Potsdam (Germany); Weidner, Kathrin [Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Climate Dynamics and Landscape Evolution, Potsdam (Germany); Forschungszentrum Juelich GmbH, Institute for Chemistry and Dynamics of the Geosphere, Juelich (Germany); Helle, Gerhard [Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Climate Dynamics and Landscape Evolution, Potsdam (Germany); Vos, Heinz [Forschungszentrum Juelich GmbH, Institute for Chemistry and Dynamics of the Geosphere, Juelich (Germany); Lindesay, Janette; Banks, John C.G. [School of Resources, Environment and Society, Australian National University, Canberra, ACT (Australia)

    2009-07-15

    Australian climate-proxy reconstructions based on tree rings from tropical and subtropical forests have not been achieved so far due to the rarity of species producing anatomically distinct annual growth rings. Our study identifies the Australian Red Cedar (Toona ciliata) as one of the most promising tree species for tree-ring research in Australasia because this species exhibits distinct annual tree rings, a prerequisite for high quality tropical dendroclimatology. Based on these preliminary studies, we were able, for the first time in subtropical and tropical Australia, to develop a statistically robust, precisely dated and annually resolved chronology back to AD1854. We show that the variability in ring widths of T. ciliata is mainly dependent on annual precipitation. The developed proxy data series contains both high- and low-frequency climate signals which can be associated with the El Nino Southern Oscillation (ENSO) and the Interdecadal Pacific Oscillation (IPO). A comparison of different data sets (Brisbane precipitation, tree rings, coral luminescence record from the Great Barrier Reef, ENSO and IPO) revealed non-stationary correlation patterns throughout the twentieth century but little instability between the new tree-ring chronology and Brisbane precipitation. (orig.)

  5. Radiocarbon concentration in modern tree rings from Valladolid, Spain

    International Nuclear Information System (INIS)

    Rakowski, Andrzej Z.; Nakamura, Toshio; Pazdur, Anna; Charro, Elena; Villanueva, Jose Luis Gutierrez; Piotrowska, Natalia

    2010-01-01

    New results of radiocarbon concentration in tree rings from the City of Valladolid (Spain) covering a growth period of 22 year have been measured using an AMS. Samples were taken using a hollow drill from a living tree, and α-cellulose was extracted from each of annual rings (early and late wood separately). The set of data shows lower radiocarbon concentration than that reported for 'clean air' at the reference station, indicating a remarkable input of 'dead' CO 2 of fossil fuel origin. Using data of carbon dioxide and 14 C concentrations from Schauinsland, the corresponding summer and winter values of the fossil component (c f ) in carbon dioxide were calculated for the City of Valladolid. By fitting exponential and linear functions to the experimental data, the exchange time was calculated, and the expected future 14 C concentration in the atmosphere was estimated.

  6. Pollution and Climate Effects on Tree-Ring Nitrogen Isotopes

    Science.gov (United States)

    Savard, M. M.; Bégin, C.; Marion, J.; Smirnoff, A.

    2009-04-01

    Georgian Bay reflect deposition of NOx emissions from cars and coal-power plants, with higher proportions from coal burning in Georgian Bay (Savard et al., 2009b). This interpretation is conceivable because recent monitoring indicates that coal-power plant NOx emissions play an important role in the annual N budget in Ontario, but they are negligible on the Quebec side. CONCLUSION Interpretations of long tree-ring N isotopic series in terms of effects generated by airborne N-species have been previously advocated. Here we further propose that the contrasted isotopic trends obtained for wood samples from two regions reflect different regional anthropogenic N deposition combined with variations of climatic conditions. This research suggests that nitrogen tree-ring series may record both regional climatic conditions and anthropogenic perturbations of the N cycle. REFERENCES Savard, M.M., Bégin,C., Marion, J., Aznar, J.-C., Smirnoff, A., 2009a. Changes of Air Quality in an urban region as inferred from tree-ring width and stable isotopes. Chapter 9 in "Relating Atmospheric Source Apportionment to Vegetation Effects: Establishing Cause Effect Relationships" (A. Legge ed.). Elsevier, Amsterdam; doi: 10.1016/S1474-8177(08)00209x. Savard, M.M., Bégin, C., Smirnoff, A., Marion, J., Rioux-Paquette, E., 2009b. Tree-ring nitrogen isotopes reflect climatic effects and anthropogenic NOx emissions. Env. Sci. Tech (doi: 10.1021/es802437k).

  7. Retrospective evaluation of tritium fallout by tree-ring analysis

    International Nuclear Information System (INIS)

    Kozak, K.; Biro, T.; Golder, F.; Rank, D.; Rajner, V.; Staudner, F.

    1993-01-01

    Tritium analyses of tree-ring cellulose were made to test its suitability for retrospective evaluation of a local tritium fallout. Several spruce trees were taken from an Austrian alpine area where tritium contamination of May 1974 precipitation had been detected. Wood from the annual growth rings of 1973, 1974 and 1975 was separated and the cellulose extracted. After isotopic equilibration with dead water, cellulose was combusted to yield water, whose tritium concentration was measured by liquid scintillation counting. Rigorous statistical treatment proved the significance of the increased tritium concentration caused by the tritium anomaly, which occurred during the growing season. The long-term trends of local atmospheric tritium, including the 1974 peak, were also well reflected by analysis of a 24-year ring sequence from a single tree in the contaminated area. The tritium data gained by the given method can be used at present qualitatively and a better understanding of the possible sources of contamination is required in order that the quantitative criteria be satisfied. (Author)

  8. Tree rings and time: recent historical studies in England

    Directory of Open Access Journals (Sweden)

    Martin Bridge

    2000-11-01

    Full Text Available By studying the annual growth rings of long-lived trees, and those preserved in ancient timbers that have survived in waterlogged or very dry conditions, it is possible to date past events in calendar years and to investigate climatic and other environmental changes. Dendrochronology has many applications, including the dating of buildings and ships and the calibration of the radiocarbon timescale that is so widely used in archaeology. Here the technique is outlined and some recent applications of it in England are described.

  9. Biological basis of tree-ring formation: a crash course

    Directory of Open Access Journals (Sweden)

    Cyrille Barthélémy Karl Rathgeber

    2016-05-01

    Full Text Available Wood is of crucial importance for man and biosphere. In this mini review, we present the fundamental processes involved in tree-ring formation and intra-annual dynamics of cambial activity, along with the influences of the environmental factors. During wood formation, new xylem cells produced by the cambium are undergoing profound transformations, passing through successive differentiation stages, which enable them to perform their functions in trees. Xylem cell formation can be divided in five major phases: (1 the division of a cambial mother cell that creates a new cell; (2 the enlargement of this newly formed cell; (3 the deposition of its secondary wall; (4 the lignification of its cell wall; and finally, (5 its programmed cell death. In most regions of the world cambial activity follows a seasonal cycle. At the beginning of the growing season, when temperature increases, the cambium resumes activity, producing new xylem cells. These cells are disposed along radial files, and start their differentiation program according to their birth date, creating typical developmental strips in the forming xylem. The width of these strips smoothly changes along the growing season. Finally, when climatic conditions deteriorate (temperature or water availability in particular, cambial activity stops, soon followed by cell enlargement, and later on by secondary wall deposition. Without a clear understanding of the xylem formation process, it is not possible to comprehend how annual growth rings and typical wood structures are formed, recording seasonal variations of the environment as well as extreme climatic events.

  10. Application of annual ring analyses to the detection of smoke damage. I. A methodical contribution to the treatment of annual ring analyses

    Energy Technology Data Exchange (ETDEWEB)

    Vins, B

    1961-01-01

    Losses in growth of silvicultural stands caused by smoke can be measured by annual ring analysis. The method is advantageous mainly because the annual gains can be checked far into the past and thus compared with gains before the onset of the pollution. Experience gained in the Krusne Hory area of Czechoslovakia with the methodical processing of 2000 annual ring analyses is reviewed. The principal problem was that more than half the trees exposed to pollution failed to grow annual rings. At first no rings are added from the ground up to a certain height; then the defect spreads all the way into the crowns of the affected trees. This observation is of fundamental importance in the calculation of losses in growth gains due to industrial emissions because hitherto the last annual ring next to the bark was always identified with the test year, while in reality a number of annual rings might already have failed to grow due to the effects of pollution. Errors far exceeding permissible limits might have occurred in the analysis.

  11. Pooled versus separate measurements of tree-ring stable isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Dorado Linan, Isabel, E-mail: isabel@gfz-potsdam.de [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Gutierrez, Emilia, E-mail: emgutierrez@ub.edu [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); Helle, Gerhard, E-mail: ghelle@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Heinrich, Ingo, E-mail: heinrich@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Andreu-Hayles, Laia, E-mail: laiandreu@ub.edu [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); Tree-Ring Laboratory, Lamont-Doherty Earth Observatory of Columbia University, Palisades NY (United States); Planells, Octavi, E-mail: leocarpus@hotmail.com [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); Leuenberger, Markus, E-mail: leuenberger@climate.unibe.ch [Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern (Switzerland); Oeschger Centre of Climate Change Research, University of Bern, Zaehringerstrasse 25, 3012 Bern (Switzerland); Buerger, Carmen, E-mail: buerger@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Schleser, Gerhard, E-mail: schleser@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany)

    2011-05-01

    {delta}{sup 13}C and {delta}{sup 18}O of tree rings contain time integrated information about the environmental conditions weighted by seasonal growth dynamics and are well established as sources of palaeoclimatic and ecophysiological data. Annually resolved isotope chronologies are frequently produced by pooling dated growth rings from several trees prior to the isotopic analyses. This procedure has the advantage of saving time and resources, but precludes from defining the isotopic error or statistical uncertainty related to the inter-tree variability. Up to now only a few studies have compared isotope series from pooled tree rings with isotopic measurements from individual trees. We tested whether or not the {delta}{sup 13}C and the {delta}{sup 18}O chronologies derived from pooled and from individual tree rings display significant differences at two locations from the Iberian Peninsula to assess advantages and constraints of both methodologies. The comparisons along the period 1900-2003 reveal a good agreement between pooled chronologies and the two mean master series which were created by averaging raw individual values (Mean) or by generating a mass calibrated mean (MassC). In most of the cases, pooled chronologies show high synchronicity with averaged individual samples at interannual scale but some differences also show up especially when comparing {delta}{sup 18}O decadal to multi-decadal variations. Moreover, differences in the first order autocorrelation among individuals may be obscured by pooling strategies. The lack of replication of pooled chronologies prevents detection of a bias due to a higher mass contribution of one sample but uncertainties associated with the analytical process itself, as sample inhomogeneity, seems to account for the observed differences. - Research Highlights: {yields} Pooled {delta}{sup 13}C and {delta}{sup 18}O chronologies are expected to be similar to the mean. {yields} Empirical pooled chronologies {delta}{sup 13}C and

  12. Pooled versus separate measurements of tree-ring stable isotopes

    International Nuclear Information System (INIS)

    Dorado Linan, Isabel; Gutierrez, Emilia; Helle, Gerhard; Heinrich, Ingo; Andreu-Hayles, Laia; Planells, Octavi; Leuenberger, Markus; Buerger, Carmen; Schleser, Gerhard

    2011-01-01

    δ 13 C and δ 18 O of tree rings contain time integrated information about the environmental conditions weighted by seasonal growth dynamics and are well established as sources of palaeoclimatic and ecophysiological data. Annually resolved isotope chronologies are frequently produced by pooling dated growth rings from several trees prior to the isotopic analyses. This procedure has the advantage of saving time and resources, but precludes from defining the isotopic error or statistical uncertainty related to the inter-tree variability. Up to now only a few studies have compared isotope series from pooled tree rings with isotopic measurements from individual trees. We tested whether or not the δ 13 C and the δ 18 O chronologies derived from pooled and from individual tree rings display significant differences at two locations from the Iberian Peninsula to assess advantages and constraints of both methodologies. The comparisons along the period 1900-2003 reveal a good agreement between pooled chronologies and the two mean master series which were created by averaging raw individual values (Mean) or by generating a mass calibrated mean (MassC). In most of the cases, pooled chronologies show high synchronicity with averaged individual samples at interannual scale but some differences also show up especially when comparing δ 18 O decadal to multi-decadal variations. Moreover, differences in the first order autocorrelation among individuals may be obscured by pooling strategies. The lack of replication of pooled chronologies prevents detection of a bias due to a higher mass contribution of one sample but uncertainties associated with the analytical process itself, as sample inhomogeneity, seems to account for the observed differences. - Research Highlights: → Pooled δ 13 C and δ 18 O chronologies are expected to be similar to the mean. → Empirical pooled chronologies δ 13 C and δ 18 O and the mean show a high synchronicity. → Pooled chronologies differ

  13. Temporal variation of tritium concentration in tree-ring cellulose over the past 50 years

    International Nuclear Information System (INIS)

    Yamada, Y.; Yasuike, K.; Komura, K.

    2004-01-01

    Concentration of organically-bound tritium in the tree-ring cellulose of a pine tree grown in Shika-machi, Ishikawa prefecture, Japan (37.1degN, 136.5degE), was measured during the ring-years from 1949 to 1999. The results were compared with those of a pine tree grown in Tatsunokuchi-machi, Ishikawa prefecture, Japan (36.4degN, 136.5degE). The annual variation of tritium in tree rings demonstrated two differences between the Shika-machi tree and the Tatsunokuchi-machi tree. No secondary peak appeared in the period after the maximum peak of 1963 for the Shika-machi tree, while two peaks appeared in 1966 and 1970 for the Tatsunokuchi-machi tree. In addition, the height of the 1963 peak was 30% higher for the Shika-machi tree than for the Tatsunokuchi-machi tree. These differences are considered to be caused by the influence that the underground water in the root zone of the Tatsunokuchi-machi tree was strongly affected by water which was transported to the tree site from mountain regions as compared to the Shika-machi tree. (author)

  14. Using Tree-Ring Data to Develop Critical Scientific and Mathematical Thinking Skills in Undergraduate Students

    Science.gov (United States)

    Fiondella, F.; Davi, N. K.; Wattenberg, F.; Pringle, P. T.; Greidanus, I.; Oelkers, R.

    2015-12-01

    Tree-ring science provides an engaging, intuitive, and relevant entryway into understanding both climate change and environmental research. It also sheds light on the process of science--from inspiration, to fieldwork, to analysis, to publishing and communication. The basic premise of dendrochronology is that annual rings reflect year-to-year environmental conditions and that by studying long-lived trees we can learn about environmental and climatic conditions going back hundreds to thousands of years. Conceptually, this makes tree-ring studies accessible to students and faculty for a number of reasons. First, in order to collect their data, dendrochronologists often launch expeditions to stunningly picturesque and remote places in search of long-lived, climate sensitive trees. The exciting stories and images that scientists bring back from the field can help connect students to the studies, their motivation, and the data collected. Second, tree rings can be more easily explained as a proxy for climate than ice cores, speleothems and others. Most people have prior knowledge about trees and annual growth rings. It is even possible, for example, for non-expert audiences to see climate variability through time with the naked eye by looking at climate-sensitive tree cores. Third, tree rings are interdisciplinary and illustrate the interplay between the mathematical sciences, the biological sciences, and the geosciences—that is, they show that the biosphere is a fundamental component of the Earth system. Here, we present online, multi-media learning modules for undergraduates that introduce students to several foundational studies in tree-ring science. These include evaluating tree-ring cores from ancient hemlock trees growing on a talus slope in New Paltz, NY to learn about drought in the Northeastern US, evaluating long-term streamflow and drought of the Colorado River based on tree-ring records, and using tree-ring dating techniques to develop construction

  15. First Gridded Spatial Field Reconstructions of Snow from Tree Rings

    Science.gov (United States)

    Coulthard, B. L.; Anchukaitis, K. J.; Pederson, G. T.; Alder, J. R.; Hostetler, S. W.; Gray, S. T.

    2017-12-01

    Western North America's mountain snowpacks provide critical water resources for human populations and ecosystems. Warmer temperatures and changing precipitation patterns will increasingly alter the quantity, extent, and persistence of snow in coming decades. A comprehensive understanding of the causes and range of long-term variability in this system is required for forecasting future anomalies, but snowpack observations are limited and sparse. While individual tree ring-based annual snowpack reconstructions have been developed for specific regions and mountain ranges, we present here the first collection of spatially-explicit gridded field reconstructions of seasonal snowpack within the American Rocky Mountains. Capitalizing on a new western North American snow-sensitive network of over 700 tree-ring chronologies, as well as recent advances in PRISM-based snow modeling, our gridded reconstructions offer a full space-time characterization of snow and associated water resource fluctuations over several centuries. The quality of reconstructions is evaluated against existing observations, proxy-records, and an independently-developed first-order monthly snow model.

  16. Stable carbon isotopic composition of tree rings from a pine tree from Augustów Wilderness, Poland, as a temperature and local environment conditions indicator.

    Science.gov (United States)

    Pawelczyk, Slawomira; Pazdur, Anna; Halas, Stanislaw

    2004-06-01

    Tree rings can be used as archives of climatic and environmental data with annual resolution. Tree rings widths, maximum late wood density and other parameters as stable composition in tree rings can be used for the reconstruction of past climatic and environmental changes. Stable carbon isotope ratios in tree rings may provide valuable information on past climatic conditions. 13C/12C ratios of plant organic matter can reflect corresponding 13C/12C ratio of atmospheric CO2 during formation of the rings. Investigations of isotopic carbon composition in tree rings from in the ecologically clean the Augustów Wilderness region in the north-eastern part of Poland (22 degrees 58'E, 53 degrees 51'N) (nowadays a sanctuary) were undertaken. Series of delta13C in alpha-cellulose and in wholewood were acquired. Those measurements constituted a part of more complex investigations of carbon isotope composition in tree rings including the measurements of radiocarbon concentration and tree ring widths. This article presents preliminary results. It is argued that contrary to the tree ring widths and delta13C in wholewood that do not reveal significant correlation with temperature, the variation of delta13C in the latewood alpha-cellulose is correlated with combined July and August temperatures. Copyright 2004 Taylor and Francis Ltd.

  17. Southwestern (U.S.A. Archaeological Tree-Ring Dating: 1930-1942

    Directory of Open Access Journals (Sweden)

    Stephen E. Nash

    1997-11-01

    Full Text Available Dendrochronology, the science of assigning precise and accurate calendar dates to annual growth rings in trees (Stokes and Smiley 1968, was the first independent dating technique available to prehistorians. Ar­chaeological tree-ring dating came of age at a time when North American archaeologists concerned them­selves primarily with time/space systematics (Willey and Sabloff 1980 and yet had no absolute and inde­pendent dating techniques available to guide their analyses. Histories of archaeology typically have not considered the development of archaeological tree-ring dating in detail. Willey and Sabloff (1980:12 devote one paragraph to the development of Southwestern archaeological tree-ring dating, as does Steibing (1993:261. Trigger (1989:305 considers dendrochronology (in the sense of the Douglass method only in light of radiocarbon dating. Textbooks and regional histories of archaeology do a little better in their treat­ment of dendrochronology, though discussions typically focus on the interpretation of tree-ring dates and not on the developmental history of the technique itself (e.g. Cordell 1984:88-90; Fagan 1991:129-133; Lyon 1996:46; Michels 1973:116; Thomas 1979:190-194. Scott (1966:9 argues that 'the story of the discovery of archaeological tree-ring dating by A E. Douglass and others has been told and retold and is now familiar to scientists and laymen alike'. I beg to differ.

  18. When tree rings go global: challenges and opportunities for retro- and prospective insights

    Science.gov (United States)

    Babst, Flurin; Bouriaud, Olivier; Poulter, Benjamin; Zhang, Zhen; Trouet, Valerie; Evans, Margaret; Charney, Noah; Record, Sydne; Enquist, Brian; Seftigen, Kristina; Björklund, Jesper; Klesse, Stefan; Bodesheim, Paul; Mahecha, Miguel; Girardin, Martin; Friend, Andrew; Frank, David

    2017-04-01

    The demand for extensive empirical data on forest growth and its climate sensitivity is growing rapidly with continued anthropogenic warming of the Earth. In principal, tree-ring records are the only resource that can provide such information along large environmental gradients and over sub-annual to centennial time scales. Yet, global tree-ring archives have remained an underrepresented resource in Earth system science. Some of the major challenges that complicate the use of existing tree-ring archives in environmental change research include: i) their limited spatial representativity for global forests, ii) varying sampling schemes that often preclude absolute estimates of forest growth, iii) different spatial and temporal resolution compared to remotely sensed and in-situ Earth observations, and iv) uncertainties arising when past climate-growth relationships are extrapolated into the future. Here we provide a perspective on possible solutions to these issues that emerged from recent and ongoing work. Regarding existing tree-ring networks, we show how spatial interpolation, statistical upscaling, and mechanistic modelling may improve their spatiotemporal coverage. An option to account for non-climatic (e.g. CO2) effects in projections of changing climate-growth relationships is also presented. Regarding future research avenues, we advocate for intensified data collection in warm regions, improved coordination with Earth observation networks, and refined concepts to integrate tree-ring data with computational estimates of forest productivity. Such efforts are expected to elevate tree-ring data as an essential component in Earth system science.

  19. Selective Tree-ring Models: A Novel Method for Reconstructing Streamflow Using Tree Rings

    Science.gov (United States)

    Foard, M. B.; Nelson, A. S.; Harley, G. L.

    2017-12-01

    Surface water is among the most instrumental and vulnerable resources in the Northwest United States (NW). Recent observations show that overall water quantity is declining in streams across the region, while extreme flooding events occur more frequently. Historical streamflow models inform probabilities of extreme flow events (flood or drought) by describing frequency and duration of past events. There are numerous examples of tree-rings being utilized to reconstruct streamflow in the NW. These models confirm that tree-rings are highly accurate at predicting streamflow, however there are many nuances that limit their applicability through time and space. For example, most models predict streamflow from hydrologically altered rivers (e.g. dammed, channelized) which may hinder our ability to predict natural prehistoric flow. They also have a tendency to over/under-predict extreme flow events. Moreover, they often neglect to capture the changing relationships between tree-growth and streamflow over time and space. To address these limitations, we utilized national tree-ring and streamflow archives to investigate the relationships between the growth of multiple coniferous species and free-flowing streams across the NW using novel species-and site-specific streamflow models - a term we coined"selective tree-ring models." Correlation function analysis and regression modeling were used to evaluate the strengths and directions of the flow-growth relationships. Species with significant relationships in the same direction were identified as strong candidates for selective models. Temporal and spatial patterns of these relationships were examined using running correlations and inverse distance weighting interpolation, respectively. Our early results indicate that (1) species adapted to extreme climates (e.g. hot-dry, cold-wet) exhibit the most consistent relationships across space, (2) these relationships weaken in locations with mild climatic variability, and (3) some

  20. Kinetics of tracheid development explain conifer tree-ring structure.

    Science.gov (United States)

    Cuny, Henri E; Rathgeber, Cyrille B K; Frank, David; Fonti, Patrick; Fournier, Meriem

    2014-09-01

    Conifer tree rings are generally composed of large, thin-walled cells of light earlywood followed by narrow, thick-walled cells of dense latewood. Yet, how wood formation processes and the associated kinetics create this typical pattern remains poorly understood. We monitored tree-ring formation weekly over 3 yr in 45 trees of three conifer species in France. Data were used to model cell development kinetics, and to attribute the relative importance of the duration and rate of cell enlargement and cell wall deposition on tree-ring structure. Cell enlargement duration contributed to 75% of changes in cell diameter along the tree rings. Remarkably, the amount of wall material per cell was quite constant along the rings. Consequently, and in contrast with widespread belief, changes in cell wall thickness were not principally attributed to the duration and rate of wall deposition (33%), but rather to the changes in cell size (67%). Cell enlargement duration, as the main driver of cell size and wall thickness, contributed to 56% of wood density variation along the rings. This mechanistic framework now forms the basis for unraveling how environmental stresses trigger deviations (e.g. false rings) from the normal tree-ring structure. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  1. Correlations and fixation of some elements in tree rings

    International Nuclear Information System (INIS)

    Goldberg, E.L.; Zolotarev, K.B.; Maksimovskaya, V.V.; Kondratyev, V.I.; Ovchinnikov, D.V.; Naurzbaev, M.M.

    2007-01-01

    High-resolution scanning with Synchrotron Radiation X-ray Fluorescence Analysis (SRXFA) was applied to investigate element distributions in tree rings. Two cores of Siberia Larch have been investigated with resolution 100-200 mkm. Two groups of elements in tree rings with different trends have been found. The members of the first group are Br, Zn, Cl, whose trends correlate with each other. Moreover, trends of Br, Zn, Cl in tree rings are similar to the trend of atmosphere precipitation in the region investigated. Other group of elements are represented by K, Ca, Sr, Mn, Fe, but their trends differ sufficiently from trend of elements of the first group. Extended fixation of elements in tree rings is observed for elements of the first group over the whole interval investigated (150 years). In contrast, elements of the second group mainly accumulate in external part of tree stem

  2. Analysis of contaminating elements in tree rings in Santiago, Chile

    International Nuclear Information System (INIS)

    Romo-Kroeger, C.M.; Avila, M.J.; Eaton, L.C.; Lopez, L.A.

    1996-01-01

    Using the 22'' isochronous cyclotron at the University of Chile, we have performed PIXE analyses on a group of samples collected from trees of metropolitan parks in Santiago. Dendrochronology was performed on each sample, which was then sectioned for the PIXE and other analyses, neutron activation and electro-chemistry. Available samples are trunk sections or cores obtained by the use of a 4.0 mm stainless steel incremental corer. We took three cores from each tree with permission of the municipalities. For the PIXE we use infinitely thick targets, as wood slabs taken along the trunk radius, and thin targets obtained by acid digestion of wood pieces and deposition on Kapton foils. Self supporting thick targets were placed directly in the PIXE chamber in a position so as to allow the irradiation of a specific annual ring. Potassium and Calcium appear as the most abundant elements in wood. Other elements such as S, Cu, Zn, As, Br and Pb were detected in amounts above the natural background in wood, and can be attributed to environmental contamination. The K/Ca ratios appear to be different for each species of tree, and seem to be related to the physico-chemical properties of wood. Preliminary results show important amounts of As and Cu (supposedly from mining origin) with increasing presence in the recent years. Pb and Zn (supposedly from vehicle origin) are also higher in recent years. (author)

  3. Analysis of contaminating elements in tree rings in Santiago, Chile

    Energy Technology Data Exchange (ETDEWEB)

    Romo-Kroeger, C.M.; Avila, M.J.; Eaton, L.C.; Lopez, L.A. [Faculty of Sciences. Univ. of Chile, Santiago (Chile)

    1996-12-31

    Using the 22`` isochronous cyclotron at the University of Chile, we have performed PIXE analyses on a group of samples collected from trees of metropolitan parks in Santiago. Dendrochronology was performed on each sample, which was then sectioned for the PIXE and other analyses, neutron activation and electro-chemistry. Available samples are trunk sections or cores obtained by the use of a 4.0 mm stainless steel incremental corer. We took three cores from each tree with permission of the municipalities. For the PIXE we use infinitely thick targets, as wood slabs taken along the trunk radius, and thin targets obtained by acid digestion of wood pieces and deposition on Kapton foils. Self supporting thick targets were placed directly in the PIXE chamber in a position so as to allow the irradiation of a specific annual ring. Potassium and Calcium appear as the most abundant elements in wood. Other elements such as S, Cu, Zn, As, Br and Pb were detected in amounts above the natural background in wood, and can be attributed to environmental contamination. The K/Ca ratios appear to be different for each species of tree, and seem to be related to the physico-chemical properties of wood. Preliminary results show important amounts of As and Cu (supposedly from mining origin) with increasing presence in the recent years. Pb and Zn (supposedly from vehicle origin) are also higher in recent years. (author)

  4. Variability of the tree-rings structure of Gmelin’s larch at northern tree line (peninsula of Taymyr

    Directory of Open Access Journals (Sweden)

    V. V. Fakhrutdinova

    2017-04-01

    Full Text Available The study of tree-ring cell structure changes as the result of tree adaptation to varying environmental conditions becomes increasingly important to predict future vegetation shifts under projected climate changes. The estimate of intrapopulation annual variability of wood anatomy characteristics is particularly informative. It helps to divide the contribution of different ecological factors to total features dispersion. In this work, a comparative analysis of individual and climatic variability of tree ring structure characteristics of Gmelin’s larch Larix gmelinii (Rupr. growth within northernmost forest was carried out. The trees from forest-tundra boundary has greater radial growth intensity, forms the bigger conductive zone in rings with wider mean lumen area in comparison with trees from closed forest. This result can be explained by adaptive features and height ecological xylem plasticity of larch. The tree rings structure of larch from boundary with tundra is determined by largely current weather conditions. Is because these ones evince high adaptive plasticity on the level of xylem structure. The xylem reflects joint changes of climate factors and local ecological conditions. The trees from closed forest are characterized by larger individual variability. The local conditions in oldest forest (for example, bad hydrothermal soil conditions inhibit the radial growth and sensitivity to environmental factors. In this case, the trees on individual level are tended to save the normal functioning of water-transport system. The significant differences in ratio individual to climate variability of tree ring structure characteristics can be caused by the different in the level of ecological habitat heterogeneity or the different in the level genetic within-population heterogeneity.

  5. Inferring biome-scale net primary productivity from tree-ring isotopes

    Science.gov (United States)

    Pederson, N.; Levesque, M.; Williams, A. P.; Hobi, M. L.; Smith, W. K.; Andreu-Hayles, L.

    2017-12-01

    Satellite estimates of vegetation growth (net primary productivity; NPP), tree-ring records, and forest inventories indicate that ongoing climate change and rising atmospheric CO2 concentration are altering productivity and carbon storage of forests worldwide. The impact of global change on the trends of NPP, however, remain unknown because of the lack of long-term high-resolution NPP data. For the first time, we tested if annually resolved carbon (δ13C) and oxygen (δ18O) stable isotopes from the cellulose of tree rings from trees in temperate regions could be used as a tool for inferring NPP across spatiotemporal scales. We compared satellite NPP estimates from the moderate-resolution imaging spectroradiometer sensor (MODIS, product MOD17A) and a newly developed global NPP dataset derived from the Global Inventory Modeling and Mapping Studies (GIMMS) dataset to annually resolved tree-ring width and δ13C and δ18O records from four sites along a hydroclimatic gradient in Eastern and Central United States. We found strong correlations across large geographical regions between satellite-derived NPP and tree-ring isotopes that ranged from -0.40 to -0.91. Notably, tree-ring derived δ18O had the strongest relation to climate. The results were consistent among the studied tree species (Quercus rubra and Liriodendron tulipifera) and along the hydroclimatic conditions of our network. Our study indicates that tree-ring isotopes can potentially be used to reconstruct NPP in time and space. As such, our findings represent an important breakthrough for estimating long-term changes in vegetation productivity at the biome scale.

  6. A study of Solar-Enso correlation with southern Brazil tree ring index (1955- 1991)

    Science.gov (United States)

    Rigozo, N.; Nordemann, D.; Vieira, L.; Echer, E.

    The effects of solar activity and El Niño-Southern Oscillation on tree growth in Southern Brazil were studied by correlation analysis. Trees for this study were native Araucaria (Araucaria Angustifolia)from four locations in Rio Grande do Sul State, in Southern Brazil: Canela (29o18`S, 50o51`W, 790 m asl), Nova Petropolis (29o2`S, 51o10`W, 579 m asl), Sao Francisco de Paula (29o25`S, 50o24`W, 930 m asl) and Sao Martinho da Serra (29o30`S, 53o53`W, 484 m asl). From these four sites, an average tree ring Index for this region was derived, for the period 1955-1991. Linear correlations were made on annual and 10 year running averages of this tree ring Index, of sunspot number Rz and SOI. For annual averages, the correlation coefficients were low, and the multiple regression between tree ring and SOI and Rz indicates that 20% of the variance in tree rings was explained by solar activity and ENSO variability. However, when the 10 year running averages correlations were made, the coefficient correlations were much higher. A clear anticorrelation is observed between SOI and Index (r=-0.81) whereas Rz and Index show a positive correlation (r=0.67). The multiple regression of 10 year running averages indicates that 76% of the variance in tree ring INdex was explained by solar activity and ENSO. These results indicate that the effects of solar activity and ENSO on tree rings are better seen on long timescales.

  7. Tree-ring analysis of ancient baldcypress trees and subfossil wood

    Science.gov (United States)

    Stahle, David W.; Burnette, Dorian J.; Villanueva, Jose; Cerano, Julian; Fye, Falko K.; Griffin, R. Daniel; Cleaveland, Malcolm K.; Stahle, Daniel K.; Edmondson, Jesse R.; Wolff, Kathryn P.

    2012-02-01

    Ancient baldcypress trees found in wetland and riverine environments have been used to develop a network of exactly dated annual ring-width chronologies extending from the southeastern United States, across Mexico, and into western Guatemala. These chronologies are sensitive to growing season precipitation in spite of frequently flooded site conditions, and have been used to reconstruct moisture levels the southeastern United States and Mexico for over 1000 years. The El Nino/Southern Oscillation (ENSO) is a major influence on the climate reconstructions derived from these baldcypress chronologies, especially in Mexico where some of the most extreme reconstructed droughts occurred during El Nino events. In the Southeast, the ENSO influence on climate and tree growth changes sign from spring to summer, and this change in dynamical forcing is recorded by sub-seasonal chronologies of earlywood and latewood width. Most existing baldcypress chronologies have been extended with tree-ring data from "subfossil" wood recovered from surface and submerged deposits. Well-preserved subfossil logs have also been recovered in quantity from buried deposits of great age, and may permit development of long continuously dated Holocene chronologies and discontinuous "floating" Pleistocene chronologies. The extensive subfossil baldcypress swamp discovered 6 m below the streets of Washington D.C. was overrun by a transgression of the Potomac estuary, possibly during the previous super interglacial (marine OIS 5e), and provides direct evidence for one potential impact of unmitigated anthropogenic warming and sea level rise.

  8. Instrumental neutron activation analysis of tree rings for dendrochemical studies

    International Nuclear Information System (INIS)

    Schaumloffel, J.C.; Filby, R.H.

    1996-01-01

    Instrumental neutron activation analysis (INAA) was employed to determine zinc, cadmium and potassium concentrations in the growth rings of ponderosa pine (Pinus ponderosa Dougl.) trees growing along the shores of Lake Roosevelt in Washington State, U.S.A. where mineral processing activities have resulted in high burdens of zinc and cadmium in the lake sediments. The tree growing along the contaminated waterway display elevated concentrations of zinc in its growth rings relative to a tree growing along an uncontaminated tributary of Lake Roosevelt. Cadmium concentrations in the growth rings from both sites are similar from 1988 to 1993. Water quality data indicate an increased concentration of cadmium in the lake from 1984 to 1988. The increased concentrations of cadmium in the lake water were reflected in apparent increases in concentrations of cadmium in individual rings of the tree sampled at the contaminated site. This suggests that translocation of cadmium in the sapwood of heartwood-forming species does not occur in the short term, and thus may not be a limiting factor in using trees as environmental monitors for cadmium. In addition, five-year tree ring segments were analyzed and subsequently reanalyzed as individual single-year ring segments. The analytical data obtained for the pooled individual rings are essentially the same as for the five-year segments, demonstrating the utility of NAA for dendrochemical studies. (author). 24 refs., 5 figs., 2 tabs

  9. Occurrence of annual growth rings in Rhizophora mangle in a region with low climate seasonality

    Directory of Open Access Journals (Sweden)

    BRUNNA T. SOUZA

    2016-01-01

    Full Text Available ABSTRACT The formation of annual growth rings has been confirmed for several mangrove species in the last decade, among which is the Rhizophora mangle. However, the record of annual rings for this species was made in a region with high hydric seasonality, a widely recognized induction factor of annual rings in tropical species. In this sense, the present study aimed to verify the occurrence of annual growth rings in R. mangle in the mangroves of Guaratiba (Rio de Janeiro, Southeastern Brazil, a region with low hydric seasonality. For this purpose, the crossdating technique was applied in ten trees collected with known age (seven years. The growth rings are characterized by alternating layers of low vessel density (earlywood and high vessel density (latewood. Multiple regression analysis indicated that growth rings width variation is driven by precipitation, water surplus, water deficit and water storage. Crossdating analysis confirmed the existence of annual growth rings in the R. mangle in Guaratiba. This discovery in a region with low hydric seasonality increases the dendrocronological potential of this species and suggests the importance of biological factors (eg. phenological behavior as complementary inductors for the formation of growth rings in this species.

  10. Reconstructing Tritium Exposure Using Tree Rings at Lawrence Berkeley National Laboratory, California

    Science.gov (United States)

    LOVE, ADAM H.; HUNT, JAMES R.; KNEZOVICH, JOHN P.

    2010-01-01

    Annual tritium exposures were reconstructed using tree cores from Pinus jeffreyi and Eucalyptus globulus near a tritiated water vapor release stack. Both tritium (3H) and carbon-14 (14C) from the wood were measured from milligram samples using accelerator mass spectrometry. Because the annual nature of the eucalyptus tree rings was in doubt, 14C measurements provided growth rates used to estimate the age for 3H determinations. A 30-yr comparison of organically bound tritium (OBT) levels to reported 3H release data is achieved using OBT measurements from three trees near the stack. The annual average 3H, determined from atmospheric water vapor monitoring stations, is comparable to the OBT in proximal trees. For situations without adequate historical monitoring data, this measurement-based historical assessment provides the only independent means of assessing exposure as compared to fate and transport models that require prior knowledge of environmental conditions and 3H discharge patterns. PMID:14572081

  11. Tree rings record 100 years of hydrologic change within a wetland

    Science.gov (United States)

    Yanosky, Thomas M.; Kappel, William M.

    1997-01-01

    One of the primary responsibilities of the Water Resources Division of the United States Geological Survey is to monitor the amount and quality of waters in our rivers, lakes, and wetlands. Hydrologists can evaluate these important resources in the present day, but how can they determine what conditions were like in past decades or even centuries? Moreover, are conditions part of a natural cycle or caused primarily by human activities? It is sometimes possible to answer these questions by examining the annual growth rings of trees. Each ring can be assigned an exact year of formation, and yearly differences in ring widths can be used to compare past and present conditions on a flood plain, along a river, or within a wetland. Thus, tree rings provide information that otherwise might be difficult or even impossible to obtain.

  12. From process to proxy: Ecological challenges and opportunities of tree-ring based environmental reconstructions

    Science.gov (United States)

    Wilmking, Martin; Buras, Allan; Heinrich, Ingo; Scharnweber, Tobias; Simard, Sonia; Smiljanic, Marko; van der Maaten, Ernst; van der Maaten-Theunissen, Marieke

    2014-05-01

    Trees are sessile, long-living organisms and as such constantly need to adapt to changing environmental conditions. Accordingly, they often show high phenotypic plasticity (the ability to change phenotypic traits, such as allocation of resources) in response to environmental change. This high phenotypic plasticity is generally considered as one of the main ingredients for a sessile organism to survive and reach high ages. Precisely because of the ability of trees to reach old age and their in-ability to simply run away when conditions get worse, growth information recorded in tree rings has long been used as a major environmental proxy, covering time scales from decades to millennia. Past environmental conditions (e.g. climate) are recorded in i.e. annual tree-ring width, early- and latewood width, wood density, isotopic concentrations, cell anatomy or wood chemistry. One prerequisite for a reconstruction is that the relationship between the environmental variable influencing tree growth and the tree-growth variable itself is stable through time. This, however, might contrast the ecological theory of high plasticity and the trees ability to adapt to change. To untangle possible mechanisms leading to stable or unstable relationships between tree growth and environmental variables, it is helpful to have exact site information and several proxy variables of each tree-ring series available. Although we gain insight into the environmental history of a sampling site when sampling today, this is extremely difficult when using archeological wood. In this latter case, we face the additional challenge of unknown origin, provenance and (or) site conditions, making it even more important to use multiple proxy time-series from the same sample. Here, we review typical examples, where the relationship between tree growth and environmental variables seems 1) stable and 2) instable through time, and relate these two cases to ecological theory. Based on ecological theory, we then

  13. Application of annual ring analyses to the determination of smoke damage. II. Contribution to the evaluation of annual ring analyses

    Energy Technology Data Exchange (ETDEWEB)

    Vins, B

    1962-01-01

    The most emission-endangered forested areas of Czechoslovakia are Krusne Hory and of Decinsky Sneznik. The condition of the forest cover today is such that not only the productivity of the forests but also their hydrological and ecological functions are in jeopardy. Measurements by annual ring analysis were made on trees at 102 selected experimental sites to determine the growth gain decrease due to air pollution. The decrease in growth gains was first noted in 1952. Up to 1958 this decrease was differentiated according to the degree of damage caused in different areas. Thus, forests in the Chomutov area exhibited a 30% damage while forests in the Most and Teplice areas exhibited a 90% damage. In the Decinsky Sneznik area the growth gain drop was already noted in 1947 and from then on the annual growth impairment was about 15%. From 1953 on, this area suffered growth gain damage of the same magnitude as the Krusne Hory area. During 1954-1958, the growth gain decreases in four areas exposed to pollution of different severity were 23, 37, 40, and 70% respectively, compared to normal growth gains of trees grown in an unpolluted environment.

  14. Carbon and nitrogen isotope variations in tree-rings as records of perturbations in regional carbon and nitrogen cycles.

    Science.gov (United States)

    Bukata, Andrew R; Kyser, T Kurtis

    2007-02-15

    Increasing anthropogenic pollution from urban centers and fossil fuel combustion can impact the carbon and nitrogen cycles in forests. To assess the impact of twentieth century anthropogenic pollution on forested system carbon and nitrogen cycles, variations in the carbon and nitrogen isotopic compositions of tree-rings were measured. Individual annual growth rings in trees from six sites across Ontario and one in New Brunswick, Canada were used to develop site chronologies of tree-ring delta 15N and delta 13C values. Tree-ring 615N values were approximately 0.5% per hundred higher and correlated with contemporaneous foliar samples from the same tree, but not with delta 15N values of soil samples. Temporal trends in carbon and nitrogen isotopic compositions of these tree-rings are consistent with increasing anthropogenic influence on both the carbon and nitrogen cycles since 1945. Tree-ring delta 13C values and delta 15N values are correlated at both remote and urban-proximal sites, with delta 15N values decreasing since 1945 and converging on 1% per hundred at urban-proximal sites and decreasing but not converging on a single delta 15N value in remote sites. These results indicate that temporal trends in tree-ring nitrogen and carbon isotopic compositions record the regional extent of pollution.

  15. Water, gravity and trees: Relationship of tree-ring widths and total water storage dynamics

    Science.gov (United States)

    Creutzfeldt, B.; Heinrich, I.; Merz, B.; Blume, T.; Güntner, A.

    2012-04-01

    Water stored in the subsurface as groundwater or soil moisture is the main fresh water source not only for drinking water and food production but also for the natural vegetation. In a changing environment water availability becomes a critical issue in many different regions. Long-term observations of the past are needed to improve the understanding of the hydrological system and the prediction of future developments. Tree ring data have repeatedly proved to be valuable sources for reconstructing long-term climate dynamics, e.g. temperature, precipitation and different hydrological variables. In water-limited environments, tree growth is primarily influenced by total water stored in the subsurface and hence, tree-ring records usually contain information about subsurface water storage. The challenge is to retrieve the information on total water storage from tree rings, because a training dataset of water stored in the sub-surface is required for calibration against the tree-ring series. However, measuring water stored in the subsurface is notoriously difficult. We here present high-precision temporal gravimeter measurements which allow for the depth-integrated quantification of total water storage dynamics at the field scale. In this study, we evaluate the relationship of total water storage change and tree ring growth also in the context of the complex interactions of other meteorological forcing factors. A tree-ring chronology was derived from a Norway spruce stand in the Bavarian Forest, Germany. Total water storage dynamics were measured directly by the superconducting gravimeter of the Geodetic Observatory Wettzell for a 9-years period. Time series were extended to 63-years period by a hydrological model using gravity data as the only calibration constrain. Finally, water storage changes were reconstructed based on the relationship between the hydrological model and the tree-ring chronology. Measurement results indicate that tree-ring growth is primarily

  16. A field-to-desktop toolchain for X-ray CT densitometry enables tree ring analysis.

    Science.gov (United States)

    De Mil, Tom; Vannoppen, Astrid; Beeckman, Hans; Van Acker, Joris; Van den Bulcke, Jan

    2016-06-01

    Disentangling tree growth requires more than ring width data only. Densitometry is considered a valuable proxy, yet laborious wood sample preparation and lack of dedicated software limit the widespread use of density profiling for tree ring analysis. An X-ray computed tomography-based toolchain of tree increment cores is presented, which results in profile data sets suitable for visual exploration as well as density-based pattern matching. Two temperate (Quercus petraea, Fagus sylvatica) and one tropical species (Terminalia superba) were used for density profiling using an X-ray computed tomography facility with custom-made sample holders and dedicated processing software. Density-based pattern matching is developed and able to detect anomalies in ring series that can be corrected via interactive software. A digital workflow allows generation of structure-corrected profiles of large sets of cores in a short time span that provide sufficient intra-annual density information for tree ring analysis. Furthermore, visual exploration of such data sets is of high value. The dated profiles can be used for high-resolution chronologies and also offer opportunities for fast screening of lesser studied tropical tree species. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Neutron activation studies of trace elements in tree rings

    International Nuclear Information System (INIS)

    Tout, R.E.; Gilboy, W.B.; Spyrou, N.M.

    1977-01-01

    The levels of twelve elements most of which are either considered essential to plant growth or have been detected in air filter samples in an air pollution survey have been monitored in three transverse sections of trees, two elms (ring-porous trees) and one cedar (a conifer). An irradiation time of 10 minutes and a waiting time of 1 minute were selected followed by a 10-minute count. The activated samples were placed on a specially shaped perspex disc situated on a 45-cm 3 Ge(Li) detector. The gamma-ray spectra were subsequently analysed on a 6600 computer, using the library program 'SAMPO' to which subroutines have been added for peak identification and for calculating the mass of elements present. All irradiations were carried out using a thermal neutron flux of 1.5x10 12 ncm -2 sec -1 . Two dimensional distributions of the elements around the tree rings of the section and radially from ring to ring, have been obtained to see if tree rings can be analysed for use as a record of historical pollution. Definite movement of most of these elements between the two main parts of the xylem has occured in all three trees. This makes it seem unlikely that any pollution products taken up from the atmosphere would be retained in the same ring in which they were originally accumulated. Exceptions may occur in the sapwood rings, where a few elements, especially Cl, show directional peaks which do not persist in the heartwood. (T.G.)

  18. Precise Dating of Flood-Plain Stratigraphy Using Changes in Tree-Ring Anatomy Following Burial

    Science.gov (United States)

    Friedman, J. M.; Shafroth, P. B.; Vincent, K. R.; Scott, M. L.; Auble, G. T.

    2001-12-01

    Determination of sediment deposition rates from stratigraphy is typically limited by a scarcity of chronological information. We present a method for precise dating of sedimentary beds based on the change in anatomy of tree rings upon burial. When stems of tamarisk (Tamarix ramosissima)and sandbar willow (Salix exigua) are buried, subsequent annual rings in the buried portions become narrower and vessels within the rings become larger. Observation of these changes can be combined with tree ring counts to determine the year of deposition of sedimentary beds that are at least 10 cm thick. Using a backhoe we dug trenches across the flood plain at three locations along the arroyo of the Rio Puerco, New Mexico. At each cross section we prepared a detailed stratigraphic description and excavated several tamarisks to depths as great as 5 meters. From each excavated tree we cut and sanded 10-50 slabs for tree-ring analysis. We cross-dated slabs within and between plants and used the burial signature in the tree rings to date all sedimentary beds in the stratigraphic profile near each plant. We then used the trench stratigraphy to convert depths of sediment deposition around individual trees to areas of deposition in the cross section. In the lower Rio Puerco introduction of tamarisk in 1926 occurred just prior to the beginning of channel narrowing and arroyo filling. Thus the tamarisks record a process of channel change to which they may have contributed. Aggradation has not been synchronous along the lower arroyo. For example, near Highway 6 and Belen, the flood plain has aggraded more than 2 m since 1970, while there has been little aggradation downstream at Bernardo. Much of the sediment deposition in levies at Highway 6 occurred during a flood in 1988. Future work will document longitudinal variation in the arroyo so that we can convert areas of sediment deposition in cross sections to volumes in the arroyo.

  19. Carbon-14 dating of tree rings for tritium measurement

    International Nuclear Information System (INIS)

    Yamada, Y.; Yasuike, K.; Kiriyama, N.; Komura, K.; Ueno, K.

    1998-01-01

    The carbon-14 concentration in tree-ring cellulose of an 80-year-old pine tree which has been used for tritium measurement was measured during the 1941-1987 period. This was done to determine the formation year of each tree ring in order to study the pathway of tritium uptake into the tree rings. In the 1941 to 1953 period, the δ 14 C value remained slightly lower than 0 per mille. It began to increase from 1954 to a small broad peak of 250 per mille between 1959 and 1961, followed by rapid increase to the highest value of approximately 800 per mille in 1964. Since 1964, it had been diminishing year by year to reach a level of 190 per mille in 1987. The two peak years coincided with those in the known carbon-14 patterns in tree rings. However, there existed a difference in the amplitude of the δ 14 C values during the period of 1963-1967. (author)

  20. How to make a tree ring: Coupling stem water flow and cambial activity in mature Alpine conifers

    Science.gov (United States)

    Peters, Richard L.; Frank, David C.; Treydte, Kerstin; Steppe, Kathy; Kahmen, Ansgar; Fonti, Patrick

    2017-04-01

    Inter-annual tree-ring measurements are used to understand tree-growth responses to climatic variability and reconstruct past climate conditions. In parallel, mechanistic models use experimentally defined plant-atmosphere interactions to explain past growth responses and predict future environmental impact on forest productivity. Yet, substantial inconsistencies within mechanistic model ensembles and mismatches with empirical data indicate that significant progress is still needed to understand the processes occurring at an intra-annual resolution that drive annual growth. However, challenges arise due to i) few datasets describing climatic responses of high-resolution physiological processes over longer time-scales, ii) uncertainties on the main mechanistic process limiting radial stem growth and iii) complex interactions between multiple environmental factors which obscure detection of the main stem growth driver, generating a gap between our understanding of intra- and inter-annual growth mechanisms. We attempt to bridge the gap between inter-annual tree-ring width and sub-daily radial stem-growth and provide a mechanistic perspective on how environmental conditions affect physiological processes that shape tree rings in conifers. We combine sub-hourly sap flow and point dendrometer measurements performed on mature Alpine conifers (Larix decidua) into an individual-based mechanistic tree-growth model to simulate sub-hourly cambial activity. The monitored trees are located along a high elevational transect in the Swiss Alps (Lötschental) to analyse the effect of increasing temperature. The model quantifies internal tree hydraulic pathways that regulate the turgidity within the cambial zone and induce cell enlargement for radial growth. The simulations are validated against intra-annual growth patterns derived from xylogenesis data and anatomical analyses. Our efforts advance the process-based understanding of how climate shapes the annual tree-ring structures

  1. Neutron activation analysis of absolutely-dated tree rings

    International Nuclear Information System (INIS)

    Uenlue, K.; Hauck, D.K.; Kuniholm, P.I.; Chiment, J.J.

    2005-01-01

    Gold concentration was determined for dendrochronologically-dated wood samples using neutron activation analysis (NAA) and correlation sought with known environmental changes, e.g., volcanic activities, during historic periods. Uptake of gold is sensitive to soil pH for many plants. Data presented are from a single, cross-dated tree that grew in Greece. Using NAA, gold was measured with parts-per-billion sensitivity in individual tree rings from 1411 to 1988 AD. (author)

  2. Imprint of the Atlantic multidecadal oscillation on tree-ring widths in northeastern Asia since 1568.

    Directory of Open Access Journals (Sweden)

    Xiaochun Wang

    Full Text Available We present a new tree-ring reconstruction of the Atlantic Multidecadal Oscillation (AMO spanning 1568-2007 CE from northeast Asia. Comparison of the instrumental AMO index, an existing tree-ring based AMO reconstruction, and this new record show strongly similar annual to multidecadal patterns of variation over the last 440 years. Warm phases of the AMO are related to increases in growth of Scots pine trees and moisture availability in northeast China and central eastern Siberia. Multi-tape method (MTM and cross-wavelet analyses indicate that robust multidecadal (∼64-128 years variability is present throughout the new proxy record. Our results have important implications concerning the influence of North Atlantic sea surface temperatures on East Asian climate, and provide support for the possibility of an AMO signature on global multidecadal climate variability.

  3. Sensitivity of ring growth and carbon allocation to climatic variation vary within ponderosa pine trees.

    Science.gov (United States)

    Kerhoulas, Lucy P; Kane, Jeffrey M

    2012-01-01

    Most dendrochronological studies focus on cores sampled from standard positions (main stem, breast height), yet vertical gradients in hydraulic constraints and priorities for carbon allocation may contribute to different growth sensitivities with position. Using cores taken from five positions (coarse roots, breast height, base of live crown, mid-crown branch and treetop), we investigated how radial growth sensitivity to climate over the period of 1895-2008 varies by position within 36 large ponderosa pines (Pinus ponderosa Dougl.) in northern Arizona. The climate parameters investigated were Palmer Drought Severity Index, water year and monsoon precipitation, maximum annual temperature, minimum annual temperature and average annual temperature. For each study tree, we generated Pearson correlation coefficients between ring width indices from each position and six climate parameters. We also investigated whether the number of missing rings differed among positions and bole heights. We found that tree density did not significantly influence climatic sensitivity to any of the climate parameters investigated at any of the sample positions. Results from three types of analyses suggest that climatic sensitivity of tree growth varied with position height: (i) correlations of radial growth and climate variables consistently increased with height; (ii) model strength based on Akaike's information criterion increased with height, where treetop growth consistently had the highest sensitivity and coarse roots the lowest sensitivity to each climatic parameter; and (iii) the correlation between bole ring width indices decreased with distance between positions. We speculate that increased sensitivity to climate at higher positions is related to hydraulic limitation because higher positions experience greater xylem tensions due to gravitational effects that render these positions more sensitive to climatic stresses. The low sensitivity of root growth to all climatic variables

  4. Modified climate with long term memory in tree ring proxies

    Czech Academy of Sciences Publication Activity Database

    Zhang, H.; Yuan, N.; Esper, J.; Werner, J. P.; Xoplaki, E.; Büntgen, Ulf; Treydte, K.; Luterbacher, J.

    2015-01-01

    Roč. 10, č. 8 (2015), č. článku 084020. ISSN 1748-9326 Institutional support: RVO:67179843 Keywords : surface-temperature * northern-hemisphere * china * variability * persistence * precipitation * fluctuations * millennium * rainfall * model * climate reconstructions * tree-ring width * maximum latewood density * frequency domains Subject RIV: EH - Ecology, Behaviour Impact factor: 4.134, year: 2015

  5. Radiocarbon measurements of tree-ring samples from Japanese woods

    International Nuclear Information System (INIS)

    Ozaki, Hiromasa; Sakamoto, Minoru; Imamura, Mineo; Mitsutani, Takumi

    2008-01-01

    Since radiocarbon age is a model age based on constancy of atmospheric radiocarbon concentration and a provisional value of 5568 years for the 14 C half-life, calibration to calendar age is required for practical dating. The dataset, called IntCal, used for the calibration has been constructed by international consortium. Most parts of the IntCal have been based on the measurement of radiocarbon in dendrochronologically dated tree-ring samples from woods in Europe and North America. Regional offsets, which are designed as differences of local atmospheric radiocarbon from IntCal, have been pointed out based on recent radiocarbon measurements for tree-ring samples from a few regions. We have also measured radiocarbon of tree-ring samples from Japanese woods in order to investigate regional offsets in Japan. In this study, radiocarbon measurements for tree-ring samples from three different Japanese woods at around AD500 were carried out. Consequently, differences from IntCal04 at around AD500 were confirmed, although no systematic offset are found. However, the results obtained in this study agree with the raw data used for construction of IntCal04. This could pose a question to calculation method of IntCal04. (author)

  6. Use of tree-ring chemistry to document historical ground-water contamination events

    Science.gov (United States)

    Vroblesky, Don A.; Yanosky, Thomas M.

    1990-01-01

    The annual growth rings of tulip trees (Liriodendron tulipifera L.) appear to preserve a chemical record of ground-water contamination at a landfill in Maryland. Zones of elevated iron and chlorine concentrations in growth rings from trees immediately downgradient from the landfill are closely correlated temporally with activities in the landfill expected to generate iron and chloride contamination in the ground water. Successively later iron peaks in trees increasingly distant from the landfill along the general direction of ground-water flow imply movement of iron-contaminated ground water away from the landfill. The historical velocity of iron movement (2 to 9 m/yr) and chloride movement (at least 40 m/yr) in ground water at the site was estimated from element-concentration trends of trees at successive distances from the landfill. The tree-ring-derived chloride-transport velocity approximates the known ground-water velocity (30 to 80 m/yr). A minimum horizontal hydraulic conductivity (0.01 to .02 cm/s) calculated from chloride velocity agrees well with values derived from aquifer tests (about 0.07 cm/s) and from ground-water modeling results (0.009 to 0.04 cm/s).

  7. Tree ring imprints of long-term changes in climate in western ...

    Indian Academy of Sciences (India)

    Prakash

    2009-10-26

    Oct 26, 2009 ... tree-ring sampling sites poses difficulty in calibrating tree-ring data against climate data especially precipitation for its strong spatial .... drained soils are its primary ecological requirement. The .... rapid radiation loss at night.

  8. Climatic Change over the 'Third Pole' from Long Tree-Ring Records

    Science.gov (United States)

    Cook, E.

    2011-12-01

    Climatic change over the Greater Himalayas and Tibetan Plateau, the 'Third Pole' of the world, is of great concern now as the Earth continues to warm at an alarming rate. While future climatic change over this region and its resulting impacts on humanity and the environment are difficult to predict with much certainty, knowing how climate has varied in the past can provide both an improved understanding of the range of variability and change that could occur in the future and the necessary context for assessing recent observed climatic change there. For this purpose, one of the best natural archives of past climate information available for study of the Third Pole environment is the changing pattern of annual ring widths found in long tree-ring chronologies. The forests of the Third Pole support many long-lived tree species, with some having life spans in excess of 1,000 years. This natural resource is steadily dwindling now due to continuing deforestation caused by human activity, but there is still enough remaining forest cover to produce a detailed network of long tree-ring chronologies for study of climate variability and change covering the past several centuries. The tree-ring records provide a mix of climate information, including that related to both temperature and precipitation. Examples of long drought-sensitive tree-ring records from the more arid parts of the Karakoram and Tibetan Plateau will be presented, along with records that primarily reflect changing temperatures in moister environments such as in Bhutan. Together they provide a glimpse of how climate of the Third Pole has changed over the past several centuries, the range of natural variability that could occur in the future independent of changes caused by greenhouse warming, and how changes during the latter part of the 20th century period of rapid global warming compare to the past.

  9. Climatically sensitive tree-ring chronologies from Crimea, Ukraine

    Science.gov (United States)

    Solomina, O.; Davi, N.; D Arrigo, R.

    2003-04-01

    Several tree species in Crimea can reach ages of 1000 years or more (Crimea..., 1999), including Taxus baccata L., Arbutus andrachne L., Quercus pubescens Willd, Quercus petraea (Mattuschka) Liebl., Quercus robur L., Juniperus excelsa M.B., and Pistacia mutica Fisch.et Mey. In September 2002, we collected samples from several long-lived tree sites described in the literature (Vulf, 1948, Ivanenko, 1951, Ena, 1983, Podgorniy, 1990), located in the mountains of Central Crimea (Sokolinoye, Chufut-Kale, Chelter) and on the coast of the Black Sea (Ai-Todor, Kharaks, Ai-Petri). The trees sampled generally had 300-350 rings. At Ai-Todor, most oaks, junipers, and pistachio showed decay. However, enough samples of oak, juniper and pine were collected to build three chronologies with good replication over the last 350 years. Long meteorological records (for Sevastopol since 1821, Ai-Petri and Yalta since the 1880's) as well as detailed historical data on extreme climatic events since 1687 (summarized by Borisov 1956) are available for this area and can be used to calibrate and verify the tree growth/climate models. Resulting dendroclimatic reconstructions will be the first from this region. The tree-ring time-series may also be used for archaeological dating of historical wood from several medieval fortresses, towns and palaces. In turn, the archaeological wood could be used to extend the tree-ring time series. Stalactites and stalagmites (Dubliansky, 1977) found in numerous caves, as well as 4000-years old laminated lake sediments (Shostakovich, 1934) are also potentially important sources of paleoclimatic information in the area.

  10. Tree rings provide early warning signals of jack pine mortality across a moisture gradient in the southern boreal forest

    Science.gov (United States)

    Mamet, S. D.; Chun, K. P.; Metsaranta, J. M.; Barr, A. G.; Johnstone, J. F.

    2015-08-01

    Recent declines in productivity and tree survival have been widely observed in boreal forests. We used early warning signals (EWS) in tree ring data to anticipate premature mortality in jack pine (Pinus banksiana)—an extensive and dominant species occurring across the moisture-limited southern boreal forest in North America. We sampled tree rings from 113 living and 84 dead trees in three soil moisture regimes (subxeric, submesic, subhygric) in central Saskatchewan, Canada. We reconstructed annual increments of tree basal area to investigate (1) whether we could detect EWS related to mortality of individual trees, and (2) how water availability and tree growth history may explain the mortality warning signs. EWS were evident as punctuated changes in growth patterns prior to transition to an alternative state of reduced growth before dying. This transition was likely triggered by a combination of severe drought and insect outbreak. Higher moisture availability associated with a soil moisture gradient did not appear to reduce tree sensitivity to stress-induced mortality. Our results suggest tree rings offer considerable potential for detecting critical transitions in tree growth, which are linked to premature mortality.

  11. Reconstructing Northeastern United States temperatures using Atlantic white cedar tree rings

    Science.gov (United States)

    Pearl, Jessie K.; Anchukaitis, Kevin J.; Pederson, Neil; Donnelly, Jeffrey P.

    2017-11-01

    Our knowledge of climate variability in the densely populated Northeastern United States is limited to instrumental data of the last century. Most regional paleoclimate proxies reflect a mix of climate responses, which makes reconstructing historical climate a challenge. Here we analyze tree-ring chronologies from Atlantic white cedar (Chamaecyparis thyoides) as a potential regional paleotemperature proxy. We evaluate our tree-ring network for spatiotemporal climate signal strength and reconstruction skill across New England. Atlantic white cedar sites in the northern section of the species’ range exhibit positive significant annual growth relationships with local and regional temperatures. Chronologies constructed from northern sites yield skillful reconstructions of temperature that reproduce centennial, multidecadal, and interannual variability in the instrumental record, providing a novel paleotemperature record for New England.

  12. Sulfur in the tree rings in Central Europe: A negative d34S shift relative to regional pollution sources

    Czech Academy of Sciences Publication Activity Database

    Novák, M.; Peiffer, S.; Žák, Karel; Jačková, I.; Buzek, F.; Erbanová, L.; Přechová, E.

    2007-01-01

    Roč. 71, 15 S1 (2007), A725-A725 ISSN 0046-564X. [Annual V. M. Goldschmidt Conference /17./. 19.08.2007-24.08.2007, Cologne] Institutional research plan: CEZ:AV0Z30130516 Keywords : sulfur isotopes * tree rings * Central Europe Subject RIV: DB - Geology ; Mineralogy

  13. An Updated Review of Dendrochronological Investigations in Mexico, a Megadiverse Country with a High Potential for Tree-Ring Sciences

    Directory of Open Access Journals (Sweden)

    Andrea C. Acosta-Hernández

    2017-05-01

    Full Text Available Dendrochronology is a very useful science to reconstruct the long-term responses of trees and other woody plants forming annual rings in response to their environment. The present review considered Mexico, a megadiverse country with a high potential for tree-ring sciences given its high climatic and environmental variability. We reviewed papers considering Mexican tree species that were published from 2001 to 2016. Most of these studies examined tree species from temperate forests, mainly in the pine and fir species. The review included 31 tree species. The most intensively sampled family and species were the Pinaceae and Douglas fir (Pseudotsuga menziessi (Mirb. Franco, respectively. Some threatened tree species were also studied. Dendrochronological investigations were mainly conducted in northern and central Mexico, with Durango being the most sampled state. The reviewed studies were mostly developed for hydroclimatic reconstructions, which were mainly based on the tree-ring width as a proxy for the climate. Tree-ring studies were carried out in both national and foreign institutions. Our review identified relevant research gaps for dendrochronologists such as: (i biomes which are still scarcely studied (e.g., tropical dry forests and (ii approaches still rarely applied to Mexican forests as dendroecology.

  14. Papers presented at the intensive seminar on 'tree rings'

    International Nuclear Information System (INIS)

    Noda, Masato

    1991-06-01

    The fourth study meeting 'Tree growth rings' was held in Tomakomai Experimental Plantation attached to the Department of Agriculture, Hokkaido University, different from what it used to be. Though the attendance and the papers presented were not many because of the distance and the improper timing, it was very delightful that the meeting became an earnest gathering. In this report, seven papers presented at the meeting are collected. (K.I.)

  15. High-latitude tree-ring data: Records of climatic change and ecological response

    International Nuclear Information System (INIS)

    Graumlich, L.J.

    1991-01-01

    Tree-ring data provide critical information regarding two fundamental questions as to the role of the polar regions in global change: (1) what is the nature of climatic variability? and (2) what is the response of vegetation to climatic variability? Tree-ring-based climatic reconstructions document the variability of the climate system on time scales of years to centuries. Dendroclimatic reconstructions indicate that the climatic episodes defined on the basis of documentary evidence in western Europe (i.e., Medieval Warm Episode, ca. A.D. 1000-1300; Little Ice Age, ca. A.D. 1550-1850) can be observed at some high-latitude sites (ex., Polar Urals). Spatial variation in long-term temperature trends (ex., northern Fennoscandia vs. Polar Urals) demonstrates the importance of regional-scale climatic controls. When collated into global networks, proxy-based climatic reconstructions can be used to test hypotheses as to the relative importance of external forcing vs. internal variation in governing climatic variation. Specifically, such a global network would allow the quantification of the climatic response to various permutations of factors thought to be important in governing decadal- to centennial-scale climatic variation. Tree populations respond to annual- to centennial-scale climatic variation through changes in rates of growth, establishment, and mortality. Tree-ring studies that document multiple aspects of high-latitude treeline dynamics (i.e., the timing of tree establishment, mortality, and changes from krummholz to upright growth) indicate a complex interaction between growth form, population processes, and environmental variability. Such interactions result in varying sensitivities of high-latitude trees to climatic change

  16. Climatic Signals in Tree Rings of Heritiera fomes Buch.-Ham. in the Sundarbans, Bangladesh.

    Science.gov (United States)

    Chowdhury, Md Qumruzzaman; De Ridder, Maaike; Beeckman, Hans

    2016-01-01

    Mangroves occur along the coastlines throughout the tropics and sub-tropics, supporting a wide variety of resources and services. In order to understand the responses of future climate change on this ecosystem, we need to know how mangrove species have responded to climate changes in the recent past. This study aims at exploring the climatic influences on the radial growth of Heritiera fomes from a local to global scale. A total of 40 stem discs were collected at breast height position from two different zones with contrasting salinity in the Sundarbans, Bangladesh. All specimens showed distinct tree rings and most of the trees (70%) could be visually and statistically crossdated. Successful crossdating enabled the development of two zone-specific chronologies. The mean radial increment was significantly higher at low salinity (eastern) zone compared to higher salinity (western) zone. The two zone-specific chronologies synchronized significantly, allowing for the construction of a regional chronology. The annual and monsoon precipitation mainly influence the tree growth of H. fomes. The growth response to local precipitation is similar in both zones except June and November in the western zone, while the significant influence is lacking. The large-scale climatic drivers such as sea surface temperature (SST) of equatorial Pacific and Indian Ocean as well as the El Niño-Southern Oscillation (ENSO) revealed no teleconnection with tree growth. The tree rings of this species are thus an indicator for monsoon precipitation variations in Bangladesh. The wider distribution of this species from the South to South East Asian coast presents an outstanding opportunity for developing a large-scale tree-ring network of mangroves.

  17. Climatic Signals in Tree Rings of Heritiera fomes Buch.-Ham. in the Sundarbans, Bangladesh.

    Directory of Open Access Journals (Sweden)

    Md Qumruzzaman Chowdhury

    Full Text Available Mangroves occur along the coastlines throughout the tropics and sub-tropics, supporting a wide variety of resources and services. In order to understand the responses of future climate change on this ecosystem, we need to know how mangrove species have responded to climate changes in the recent past. This study aims at exploring the climatic influences on the radial growth of Heritiera fomes from a local to global scale. A total of 40 stem discs were collected at breast height position from two different zones with contrasting salinity in the Sundarbans, Bangladesh. All specimens showed distinct tree rings and most of the trees (70% could be visually and statistically crossdated. Successful crossdating enabled the development of two zone-specific chronologies. The mean radial increment was significantly higher at low salinity (eastern zone compared to higher salinity (western zone. The two zone-specific chronologies synchronized significantly, allowing for the construction of a regional chronology. The annual and monsoon precipitation mainly influence the tree growth of H. fomes. The growth response to local precipitation is similar in both zones except June and November in the western zone, while the significant influence is lacking. The large-scale climatic drivers such as sea surface temperature (SST of equatorial Pacific and Indian Ocean as well as the El Niño-Southern Oscillation (ENSO revealed no teleconnection with tree growth. The tree rings of this species are thus an indicator for monsoon precipitation variations in Bangladesh. The wider distribution of this species from the South to South East Asian coast presents an outstanding opportunity for developing a large-scale tree-ring network of mangroves.

  18. Wood density variation and tree ring distinctness in Gmelina arborea trees by x-ray densitometry

    Directory of Open Access Journals (Sweden)

    Roger Moya

    2009-03-01

    Full Text Available Due to its relationship with other properties, wood density is the main wood quality parameter. Modern, accuratemethods such as X-ray densitometry - are applied to determine the spatial distribution of density in wood sections and to evaluatewood quality. The objectives of this study were to determinate the influence of growing conditions on wood density variation andtree ring demarcation of gmelina trees from fast growing plantations in Costa Rica. The wood density was determined by X-raydensitometry method. Wood samples were cut from gmelina trees and were exposed to low X-rays. The radiographic films weredeveloped and scanned using a 256 gray scale with 1000 dpi resolution and the wood density was determined by CRAD and CERDsoftware. The results showed tree-ring boundaries were distinctly delimited in trees growing in site with rainfall lower than 2510 mm/year. It was demonstrated that tree age, climatic conditions and management of plantation affects wood density and its variability. Thespecific effect of variables on wood density was quantified by for multiple regression method. It was determined that tree yearexplained 25.8% of the total variation of density and 19.9% were caused by climatic condition where the tree growing. Wood densitywas less affected by the intensity of forest management with 5.9% of total variation.

  19. Gridded Snow Water Equivalent Reconstruction for Utah Using Forest Inventory and Analysis Tree-Ring Data

    Directory of Open Access Journals (Sweden)

    Daniel Barandiaran

    2017-06-01

    Full Text Available Snowpack observations in the Intermountain West are sparse and short, making them difficult for use in depicting past variability and extremes. This study presents a reconstruction of April 1 snow water equivalent (SWE for the period of 1850–1989 using increment cores collected by the U.S. Forest Service, Interior West Forest Inventory and Analysis program (FIA. In the state of Utah, SWE was reconstructed for 38 snow course locations using a combination of standardized tree-ring indices derived from both FIA increment cores and publicly available tree-ring chronologies. These individual reconstructions were then interpolated to a 4-km grid using an objective analysis with elevation correction to create an SWE product. The results showed a significant correlation with observed SWE as well as good correspondence to regional tree-ring-based drought reconstructions. Diagnostic analysis showed statewide coherent climate variability on inter-annual and inter-decadal time-scales, with added geographical details that would not be possible using courser pre-instrumental proxy datasets. This SWE reconstruction provides water resource managers and forecasters with better spatial resolution to examine past variability in snowpack, which will be important as future hydroclimatic variability is amplified by climate change.

  20. Increase of radiocarbon concentration in tree rings from Kujawy (SE Poland) around AD 774-775

    Science.gov (United States)

    Rakowski, Andrzej Z.; Krąpiec, Marek; Huels, Mathias; Pawlyta, Jacek; Dreves, Alexander; Meadows, John

    2015-10-01

    Evidence of a rapid increase in atmospheric radiocarbon (14C) content in AD 774-775 was presented by Miyake et al. (2012), who observed an increase of about 12‰ in the 14C content in annual tree rings from Japanese cedar. Usoskin et al. (2013) report a similar 14C spike in German oak, and attribute it to exceptional solar activity. If this phenomenon is global in character, such rapid changes in 14C concentration may affect the accuracy of calibrated dates, as the existing calibration curve is composed mainly of decadal samples. Single-year samples of dendro-chronologically dated tree rings of deciduous oak (Quercus robur) from Kujawy, a village near Krakow (SE Poland), spanning the years AD 765-796, were collected and their 14C content was measured using the AMS system in the Leibniz Laboratory. The results clearly show a rapid increase of 9.2 ± 2.1‰ in the 14C concentration in tree rings between AD 774 and AD 775, with maximum Δ14C = 4.1 ± 2.3‰ noted in AD 776.

  1. Increase of radiocarbon concentration in tree rings from Kujawy (SE Poland) around AD 774–775

    International Nuclear Information System (INIS)

    Rakowski, Andrzej Z.; Krąpiec, Marek; Huels, Mathias; Pawlyta, Jacek; Dreves, Alexander; Meadows, John

    2015-01-01

    Evidence of a rapid increase in atmospheric radiocarbon ( 14 C) content in AD 774–775 was presented by Miyake et al. (2012), who observed an increase of about 12‰ in the 14 C content in annual tree rings from Japanese cedar. Usoskin et al. (2013) report a similar 14 C spike in German oak, and attribute it to exceptional solar activity. If this phenomenon is global in character, such rapid changes in 14 C concentration may affect the accuracy of calibrated dates, as the existing calibration curve is composed mainly of decadal samples. Single-year samples of dendro-chronologically dated tree rings of deciduous oak (Quercus robur) from Kujawy, a village near Krakow (SE Poland), spanning the years AD 765–796, were collected and their 14 C content was measured using the AMS system in the Leibniz Laboratory. The results clearly show a rapid increase of 9.2 ± 2.1‰ in the 14 C concentration in tree rings between AD 774 and AD 775, with maximum Δ 14 C = 4.1 ± 2.3‰ noted in AD 776.

  2. Increase of radiocarbon concentration in tree rings from Kujawy (SE Poland) around AD 774–775

    Energy Technology Data Exchange (ETDEWEB)

    Rakowski, Andrzej Z., E-mail: arakowski@polsl.pl [Leibniz-Laboratory for Radiometric Dating and Isotope Research, University Kiel, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Institute of Physics – Center for Science and Education, Silesian University of Technology, Konarskiego Str. 22B, 44-100 Gliwice (Poland); Krąpiec, Marek [AGH University of Science and Technology, Mickiewicza Av. 30, 30-059 Krakow (Poland); Huels, Mathias [Leibniz-Laboratory for Radiometric Dating and Isotope Research, University Kiel, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Pawlyta, Jacek [Institute of Physics – Center for Science and Education, Silesian University of Technology, Konarskiego Str. 22B, 44-100 Gliwice (Poland); Dreves, Alexander [Leibniz-Laboratory for Radiometric Dating and Isotope Research, University Kiel, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Meadows, John [Leibniz-Laboratory for Radiometric Dating and Isotope Research, University Kiel, Max-Eyth-Str. 11-13, 24118 Kiel (Germany); Centre for Baltic and Scandinavian Archaeology, Schleswig-Holstein State Museums Foundation, Schloss Gottorf, Schloßinsel, 24837 Schleswig (Germany)

    2015-10-15

    Evidence of a rapid increase in atmospheric radiocarbon ({sup 14}C) content in AD 774–775 was presented by Miyake et al. (2012), who observed an increase of about 12‰ in the {sup 14}C content in annual tree rings from Japanese cedar. Usoskin et al. (2013) report a similar {sup 14}C spike in German oak, and attribute it to exceptional solar activity. If this phenomenon is global in character, such rapid changes in {sup 14}C concentration may affect the accuracy of calibrated dates, as the existing calibration curve is composed mainly of decadal samples. Single-year samples of dendro-chronologically dated tree rings of deciduous oak (Quercus robur) from Kujawy, a village near Krakow (SE Poland), spanning the years AD 765–796, were collected and their {sup 14}C content was measured using the AMS system in the Leibniz Laboratory. The results clearly show a rapid increase of 9.2 ± 2.1‰ in the {sup 14}C concentration in tree rings between AD 774 and AD 775, with maximum Δ{sup 14}C = 4.1 ± 2.3‰ noted in AD 776.

  3. Evaluation of Whole Tree Growth Increment Derived from Tree-Ring Series for Use in Assessments of Changes in Forest Productivity across Various Spatial Scales

    Directory of Open Access Journals (Sweden)

    Juha M. Metsaranta

    2016-12-01

    Full Text Available The inherent predictability of inter-annual variation in forest productivity remains unknown. Available field-based data sources for understanding this variability differ in their spatial resolution, temporal resolution, and typical units of measure. Nearly all other tree and forest characteristics are in practice derived from measurements of diameter at breast height (DBH. Therefore, diameter increment reconstructed annually from tree-ring data can be used to estimate annual growth increments of wood volume, but the accuracy and precision of these estimates requires assessment. Annual growth estimates for n = 170 trees sampled for whole stem analysis from five tree species (jack pine, lodgepole pine, black spruce, white spruce, and trembling aspen in Western Canada were compared against increments derived from breast height measurements only. Inter-annual variability of breast height and whole tree growth increments was highly correlated for most trees. Relative errors varied by species, diameter class, and the equation used to estimate volume (regional vs. national. A simple example of the possible effect of this error when propagated to the stand level is provided.

  4. Stable carbon isotopes and drought signal in the tree-rings of northern white-cedar trees from boreal central Canada. (Invited)

    Science.gov (United States)

    Tardif, J. C.; Au, R.

    2010-12-01

    Despite the demonstrated value of tree-ring δ13C analysis, there have been a limited number of dendroisotopic δ13C studies conducted throughout the North American boreal forest. Dendroisotopic series are generally short and few tree species/habitats have been investigated. We present recent work conducted in the boreal forest of Manitoba, central Canada. Old northern white-cedar (Thuja occidentalis L.) trees were sampled at their northwestern limit of distribution. The objectives of the study were 1) to determine the major climatic factors associated with each of the ring-width and δ13C chronology and 2) to provide a multi-century inference of drought events based on tree-ring δ13C and ring width analyses. We also compared the δ13C chronology developed from Thuja occidentalis trees to that of white spruce (Picea glauca Moench) and jack pine (Pinus banksiana Lamb.) trees developed in northern Manitoba. Fifteen T. occidentalis trees were selected for δ13C analysis and holocellulose was isolated from each tree-ring through standard chemical extraction techniques. The annually resolved δ13C chronology spanned from 1650 to 2006 A.D. and incorporated dead and living T. occidentalis trees selected from two sites. Hydric organic conditions on horizontal topography punctuated by scattered wet depressions prevailed at both sites. A ring-width chronology was also developed from both dead and living T. occidentalis trees from the region. All chronology development followed standardization of each of the δ13C series using a 60-year cubic spline function with a 50% frequency response. Results indicated that ring width was more often associated with climate conditions prevailing in the year prior to ring formation compared to the δ13C values. During the year of ring-formation, ring width was associated with spring and early summer conditions whereas, δ13C was more indicative of overall summer conditions. Conditions conducive to moisture stress were however important for

  5. Bivariate Drought Analysis Using Streamflow Reconstruction with Tree Ring Indices in the Sacramento Basin, California, USA

    Directory of Open Access Journals (Sweden)

    Jaewon Kwak

    2016-03-01

    Full Text Available Long-term streamflow data are vital for analysis of hydrological droughts. Using an artificial neural network (ANN model and nine tree-ring indices, this study reconstructed the annual streamflow of the Sacramento River for the period from 1560 to 1871. Using the reconstructed streamflow data, the copula method was used for bivariate drought analysis, deriving a hydrological drought return period plot for the Sacramento River basin. Results showed strong correlation among drought characteristics, and the drought with a 20-year return period (17.2 million acre-feet (MAF per year in the Sacramento River basin could be considered a critical level of drought for water shortages.

  6. Studying global change through investigation of the plastic responses of xylem anatomy in tree rings.

    Science.gov (United States)

    Fonti, Patrick; von Arx, Georg; García-González, Ignacio; Eilmann, Britta; Sass-Klaassen, Ute; Gärtner, Holger; Eckstein, Dieter

    2010-01-01

    Variability in xylem anatomy is of interest to plant scientists because of the role water transport plays in plant performance and survival. Insights into plant adjustments to changing environmental conditions have mainly been obtained through structural and functional comparative studies between taxa or within taxa on contrasting sites or along environmental gradients. Yet, a gap exists regarding the study of hydraulic adjustments in response to environmental changes over the lifetimes of plants. In trees, dated tree-ring series are often exploited to reconstruct dynamics in ecological conditions, and recent work in which wood-anatomical variables have been used in dendrochronology has produced promising results. Environmental signals identified in water-conducting cells carry novel information reflecting changes in regional conditions and are mostly related to short, sub-annual intervals. Although the idea of investigating environmental signals through wood anatomical time series goes back to the 1960s, it is only recently that low-cost computerized image-analysis systems have enabled increased scientific output in this field. We believe that the study of tree-ring anatomy is emerging as a promising approach in tree biology and climate change research, particularly if complemented by physiological and ecological studies. This contribution presents the rationale, the potential, and the methodological challenges of this innovative approach.

  7. Sponge 'tree rings' : new indicators of ocean variability?

    International Nuclear Information System (INIS)

    Ellwood, M.; Kelly, M.

    2003-01-01

    Certain marine sponges offer a unique approach to the problem of recording environmental change. These sponges and their spicules grow by putting on concentric layers of silica material on a seasonal basis, rather like tree rings. The concentrations of certain chemicals in the surrounding water, and the growth rate of the sponge itself, are archived in the silica deposited. The information in each layer of silica can be used to deduce environmental conditions on a range of scales; years, decades and centuries. (author). 7 figs

  8. Radiocarbon concentration in modern tree rings from Fukushima, Japan

    DEFF Research Database (Denmark)

    Xu, Sheng; Cook, Gordon T.; Cresswell, Alan J.

    2015-01-01

    A 30-year-old Japanese cedar (Cryptomeria japonica), collected from Iwaki, Fukushima in 2014, was analyzed for the long-lived radionuclide 14C. Values of δ14C varied from 211.7‰ in 1984 to 16.9‰ in 2013. The temporal δ14C variation can be described as an exponential decline, indistinguishable from.......e. fossil carbon) source. This change coincides with local traffic increases since two nearby expressways were opened in the 1990's. In addition, the small but visible 14C pulse observed in the 2011 tree-ring might be caused by release from the damaged reactors during the Fukushima nuclear accident....

  9. Radiocarbon concentration in modern tree rings from Fukushima, Japan

    International Nuclear Information System (INIS)

    Xu, Sheng; Cook, Gordon T.; Cresswell, Alan J.; Dunbar, Elaine; Freeman, Stewart P.H.T.; Hastie, Helen; Hou, Xiaolin; Jacobsson, Piotr; Naysmith, Philip; Sanderson, David C.W.

    2015-01-01

    A 30-year-old Japanese cedar (Cryptomeria japonica), collected from Iwaki, Fukushima in 2014, was analyzed for the long-lived radionuclide 14 C. Values of Δ 14 C varied from 211.7‰ in 1984 to 16.9‰ in 2013. The temporal Δ 14 C variation can be described as an exponential decline, indistinguishable from the general Northern Hemisphere Zone 2 (NH Zone 2) values in the atmosphere, until at least 1994. Values of Δ 14 C for 1999 and 2004 are slightly depleted compared with NH Zone 2 values, while from 1999 to 2013 the data suggest a clear depletion with a 2–8 ppmV additional CO 2 contribution from a 14 C-free (i.e. fossil carbon) source. This change coincides with local traffic increases since two nearby expressways were opened in the 1990's. In addition, the small but visible 14 C pulse observed in the 2011 tree-ring might be caused by release from the damaged reactors during the Fukushima nuclear accident. - Highlights: • We measured 14 C activity in modern tree rings in a 30-year-old Japanese cedar from Fukushima. • The temporal Δ 14 C variation is ascribed as an exponential decline. • The local traffic increases caused a clear 14 C deletion since 1990's. • Small 14 C might be released during the Fukushima nuclear accident

  10. Tree rings and rainfall in the equatorial Amazon

    Science.gov (United States)

    Granato-Souza, Daniela; Stahle, David W.; Barbosa, Ana Carolina; Feng, Song; Torbenson, Max C. A.; de Assis Pereira, Gabriel; Schöngart, Jochen; Barbosa, Joao Paulo; Griffin, Daniel

    2018-05-01

    The Amazon basin is a global center of hydroclimatic variability and biodiversity, but there are only eight instrumental rainfall stations with continuous records longer than 80 years in the entire basin, an area nearly the size of the coterminous US. The first long moisture-sensitive tree-ring chronology has been developed in the eastern equatorial Amazon of Brazil based on dendrochronological analysis of Cedrela cross sections cut during sustainable logging operations near the Rio Paru. The Rio Paru chronology dates from 1786 to 2016 and is significantly correlated with instrumental precipitation observations from 1939 to 2016. The strength and spatial scale of the precipitation signal vary during the instrumental period, but the Rio Paru chronology has been used to develop a preliminary reconstruction of February to November rainfall totals from 1786 to 2016. The reconstruction is related to SSTs in the Atlantic and especially the tropical Pacific, similar to the stronger pattern of association computed for the instrumental rainfall data from the eastern Amazon. The tree-ring data estimate extended drought and wet episodes in the mid- to late-nineteenth century, providing a valuable, long-term perspective on the moisture changes expected to emerge over the Amazon in the coming century due to deforestation and anthropogenic climate change.

  11. δ13C of Tree-Ring Lignin as an Indirect Measure of Climate Change

    International Nuclear Information System (INIS)

    Robertson, I.; Loader, N. J.; McCarroll, D.; Carter, A. H. C.; Cheng, L.; Leavitt, S. W.

    2004-01-01

    High-resolution paleoclimatic data are an essential requirement for testing numerical models of climate change and the global carbon cycle. If the long tree-ring chronologies, originally established for the purpose of dendrochronology, are to be fully exploited as an indirect measure of past climatic variability, additional techniques are required to obtain this information. The determination of the δ 13 C value of tree-ring cellulose has been used successfully to reconstruct past climates. However, under both aerobic and anaerobic conditions, the polysaccharide components of vascular plants (mainly cellulose and hemicelluloses) are more prone to rapid degradation than lignin. This has serious implications for the use of carbon isotope values of tree-ring cellulose as an indirect measure of past climates. An absolutely dated ring-width chronology was established for oaks (Quercus robur L.) growing at Sandringham Park in eastern England. Carbon isotope values were determined on α-cellulose and 'Klason' lignin isolated from annual latewood samples over the period AD 1895-1999. The carbon isotope values of earlywood lignin are correlated with the latewood carbon isotope values of the previous year, supporting the theory that some of the carbon utilised in earlywood synthesis is assimilated in the previous year. The high-frequency variance in the carbon isotope indices of latewood lignin and cellulose is highly correlated with combined July and August environmental variables, indicating that they were formed at similar times. There was no evidence of secondary lignification. These results demonstrate that the determination of carbon isotope values of latewood lignin offers the potential to obtain unambiguous proxy climatic data covering several millennia

  12. Six centuries of May-July precipitation in Cyprus from tree rings

    Science.gov (United States)

    Touchan, Ramzi; Christou, Andreas K.; Meko, David M.

    2014-12-01

    A May-July precipitation nested reconstruction for the period AD 1415-2010 was developed from multi-century tree-ring records of Pinus nigra, Pinus brutia, and Cedrus brevifolia for Cyprus. Calibration and verification statistics for the period 1917-2010 show a good level of skill, and split-sample validation over 1917-2010 supports temporal stability of the tree-ring signal for precipitation. Smoothed annual time series of reconstructed precipitation and a tally of drought events in a moving time window indicate that the calibration period is not representative of the full range of drought variability. While convective precipitation in the warm season may be driven strongly by local factors, composite maps of geopotential height anomaly for dry years and wet years support large-scale atmospheric-flow influence related to height anomalies over the broader region of northeast Africa and the eastern Mediterranean. Emerging positive trend in reconstruction residuals may be an early sign of exacerbation of drought stress on trees by recent warming in May-July. Future warming expected from increases in greenhouse gases poses a threat to forest resources in Cyprus and elsewhere in the Mediterranean.

  13. Summer precipitation influences the stable oxygen and carbon isotopic composition of tree-ring cellulose in Pinus ponderosa.

    Science.gov (United States)

    Roden, John S; Ehleringer, James R

    2007-04-01

    The carbon and oxygen isotopic composition of tree-ring cellulose was examined in ponderosa pine (Pinus ponderosa Dougl.) trees in the western USA to study seasonal patterns of precipitation inputs. Two sites (California and Oregon) had minimal summer rainfall inputs, whereas a third site (Arizona) received as much as 70% of its annual precipitation during the summer months (North American monsoon). For the Arizona site, both the delta(18)O and delta(13)C values of latewood cellulose increased as the fraction of annual precipitation occurring in the summer (July through September) increased. There were no trends in latewood cellulose delta(18)O with the absolute amount of summer rain at any site. The delta(13)C composition of latewood cellulose declined with increasing total water year precipitation for all sites. Years with below-average total precipitation tended to have a higher proportion of their annual water inputs during the summer months. Relative humidity was negatively correlated with latewood cellulose delta(13)C at all sites. Trees at the Arizona site produced latewood cellulose that was significantly more enriched in (18)O compared with trees at the Oregon or California site, implying a greater reliance on an (18)O-enriched water source. Thus, tree-ring records of cellulose delta(18)O and delta(13)C may provide useful proxy information about seasonal precipitation inputs and the variability and intensity of the North American monsoon.

  14. Relating ring width of Mediterranean evergreen species to seasonal and annual variations of precipitation and temperature

    Directory of Open Access Journals (Sweden)

    W. Nijland

    2011-05-01

    Full Text Available Plant growth in Mediterranean landscapes is limited by the typical summer-dry climate. Forests in these areas are only marginally productive and may be quite susceptible to modern climate change. To improve our understanding of forest sensitivity to annual and seasonal climatic variability, we use tree-ring measurements of two Mediterranean evergreen tree species: Quercus ilex L. and Arbutus unedo L. We sampled 34 stems of these species on three different types of substrates in the Peyne study area in southern France. The resulting chronologies were analysed in combination with 38 yr of monthly precipitation and temperature data to reconstruct the response of stem growth to climatic variability. Results indicate a strong positive response to May and June precipitation, as well as a significant positive influence of early-spring temperatures and a negative growth response to summer heat. Comparison of the data with more detailed productivity measurements in two contrasting years confirms these observations and shows a strong productivity limiting effect of low early-summer precipitation. The results show that tree-ring data from Q.ilex and A.unedo can provide valuable information about the response of these tree species to climate variability, improving our ability to predict the effects of climate change in Mediterranean ecosystems.

  15. Relating ring width of Mediterranean evergreen species to seasonal and annual variations of precipitation and temperature

    Science.gov (United States)

    Nijland, W.; Jansma, E.; Addink, E. A.; Domínguez Delmás, M.; de Jong, S. M.

    2011-05-01

    Plant growth in Mediterranean landscapes is limited by the typical summer-dry climate. Forests in these areas are only marginally productive and may be quite susceptible to modern climate change. To improve our understanding of forest sensitivity to annual and seasonal climatic variability, we use tree-ring measurements of two Mediterranean evergreen tree species: Quercus ilex L. and Arbutus unedo L. We sampled 34 stems of these species on three different types of substrates in the Peyne study area in southern France. The resulting chronologies were analysed in combination with 38 yr of monthly precipitation and temperature data to reconstruct the response of stem growth to climatic variability. Results indicate a strong positive response to May and June precipitation, as well as a significant positive influence of early-spring temperatures and a negative growth response to summer heat. Comparison of the data with more detailed productivity measurements in two contrasting years confirms these observations and shows a strong productivity limiting effect of low early-summer precipitation. The results show that tree-ring data from Q.ilex and A.unedo can provide valuable information about the response of these tree species to climate variability, improving our ability to predict the effects of climate change in Mediterranean ecosystems.

  16. Hydroclimate variability in southwestern Japan over the last 1500 years reconstructed from oxygen isotope ratios in tree rings

    Science.gov (United States)

    Sano, Masaki; Yasue, Koh; Kimura, Katsuhiko; Nakatsuka, Takeshi

    2015-04-01

    Recent progress in isotope dendroclimatology indicates that tree-ring δ18O is a promising proxy to precisely reconstruct hydroclimate variability in monsoon Asia. Here we present a 1500-year-long tree-ring δ18O chronology constructed using living and fallen dead trees (Cryptomeria japonia) that were collected in Yakushima Island, southwestern Japan. Core or disc samples were cross-dated by visually matching ring-width patterns. Then, a total of 14 trees were selected for isotopic analysis. We employed the 'plate method' to extract cellulose directly from a 1.0-mm thick wood plate, in order to facilitate the processing of hundreds of rings simultaneously. Each annual ring of cellulose was separated using a razor blade, and its δ18O value was determined using a continuous flow isotope ratio mass spectrometer coupled to an elemental analyzer. The resultant δ18O time series were highly correlated with one another (Rbar: 0.66), indicating that common signals related to regional climate are preserved in all the sampled trees. Since the δ18O series did not show prominent age-related trends, all the series were simply normalized to have the same mean for the overlapping segments. The resulting series were then averaged to build the final chronology. Response analysis with ambient meteorological records for the last 50 years indicates that tree-ring δ18O is mainly controlled by summer (May-September) relative humidity. We therefore interpret our record as a proxy of hydroclimate related to East Asian summer monsoon. Overall low-frequency variations in our chronology are similar to those of a Northern Hemisphere temperature reconstruction. Specifically our record shows a relatively dry (wet) condition during the Medieval Warm Period (the Little Ice Age). Centennial-scale fluctuations of sea surface temperatures in the equatorial Pacific may play a role in modulating long-term hydroclimate changes in southwestern Japan.

  17. Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO(2) assimilation and growth in Douglas-fir.

    Science.gov (United States)

    Saffell, Brandy J; Meinzer, Frederick C; Voelker, Steven L; Shaw, David C; Brooks, J Renée; Lachenbruch, Barbara; McKay, Jennifer

    2014-07-01

    Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible reference species (western hemlock, Tsuga heterophylla) to evaluate their use as proxies for variation in past SNC infection, particularly in relation to potential explanatory climate factors. We sampled trees from an Oregon site where a fungicide trial took place from 1996 to 2000, which enabled the comparison of stable isotope values between trees with and without disease. Carbon stable isotope discrimination (Δ(13)C) of treated Douglas-fir tree-rings was greater than that of untreated Douglas-fir tree-rings during the fungicide treatment period. Both annual growth and tree-ring Δ(13)C increased with treatment such that treated Douglas-fir had values similar to co-occurring western hemlock during the treatment period. There was no difference in the tree-ring oxygen stable isotope ratio between treated and untreated Douglas-fir. Tree-ring Δ(13)C of diseased Douglas-fir was negatively correlated with relative humidity during the two previous summers, consistent with increased leaf colonization by SNC under high humidity conditions that leads to greater disease severity in following years. © 2013 John Wiley & Sons Ltd.

  18. The nuclear bomb carbon curve recorded in tree-rings and lake sediments near Taal Volcano, Central Philippines

    Science.gov (United States)

    Liou, M. S.; Li, H. C.; Huang, S. K.; Guan, B. T.

    2017-12-01

    Dendrochronologies built from precisely dated annual rings have shown to record the regional bomb pulse and the C-14 concentration variations caused by local events. In this study, we collected teak trees Tectona grandis near the Lake Taal, Central Philippines in 2011 for dendrochronological analysis and radiocarbon dating. The tree-ring sample contains 90 rings dated from 1922 to 2011. Currently, 28 selected subsamples have been measured by AMS 14C on bulk carbon with a few samples on holocellulose. The 14C results of the samples indicate that: 1) the results of AMS 14C dating between holocellulose and whole wood from the same ring are similar, so we select whole wood for AMS 14C dating. 2) The nuclear bomb 14C pulse was clearly recorded in the Tectona grandis growth rings. The Δ14C values rose dramatically in 1960 and reached a maximum of 692‰ in 1966. The magnitude and the peak year of the bomb curve in the Tectona grandis tree-ring record are comparable to other published tree-ring records in the tropical regions. 3) The Δ14C values suddenly dropped in 1950, 1964 and 1968, probably affected by CO2 gas releasing due to the Taal volcanic activities. Further study on the tree-ring 14C dating will allow us to evaluate the bomb pulse trends more precisely, and the volcanic activities of Pinatubo and Taal Volcanoes. The tree-ring Δ14C record not only confirms existence of the bomb curve in Taal Lake area, but also allows us compare to the Δ14C record in the lake sediment for chronological construction. A 120-cm gravity core, TLS-2, collected from Lake Taal in 2008, shows the nuclear bomb carbon curve in the TOC of the core. However, the magnitude of the nuclear bomb 14C pulse in the TOC of TLS-2 is much lower than that in the tree-ring records, due to mixing effect of different organic carbon sources, smoothing effect of 14CO2 in multiple years plant growths, local old CO2 emission from volcanic activity, degassing from the lake bottom, and industrial and city

  19. Deconvolution of the tree ring based delta13C record

    International Nuclear Information System (INIS)

    Peng, T.; Broecker, W.S.; Freyer, H.D.; Trumbore, S.

    1983-01-01

    We assumed that the tree-ring based 13 C/ 12 C record constructed by Freyer and Belacy (1983) to be representative of the fossil fuel and forest-soil induced 13 C/ 12 C change for atmospheric CO 2 . Through the use of a modification of the Oeschger et al. ocean model, we have computed the contribution of the combustion of coal, oil, and natural gas to this observed 13 C/ 12 C change. A large residual remains when the tree-ring-based record is corrected for the contribution of fossil fuel CO 2 . A deconvolution was performed on this residual to determine the time history and magnitude of the forest-soil reservoir changes over the past 150 years. Several important conclusions were reached. (1) The magnitude of the integrated CO 2 input from these sources was about 1.6 times that from fossil fuels. (2) The forest-soil contribution reached a broad maximum centered at about 1900. (3) Over the 2 decade period covered by the Mauna Loa atmospheric CO 2 content record, the input from forests and soils was about 30% that from fossil fuels. (4) The 13 C/ 12 C trend over the last 20 years was dominated by the input of fossil fuel CO 2 . (5) The forest-soil release did not contribute significantly to the secular increase in atmospheric CO 2 observed over the last 20 years. (6) The pre-1850 atmospheric p2 values must have been in the range 245 to 270 x 10 -6 atmospheres

  20. The impact of tree age on biomass growth and carbon accumulation capacity: A retrospective analysis using tree ring data of three tropical tree species grown in natural forests of Suriname.

    Science.gov (United States)

    Köhl, Michael; Neupane, Prem R; Lotfiomran, Neda

    2017-01-01

    The world's forests play a pivotal role in the mitigation of global climate change. By photosynthesis they remove CO2 from the atmosphere and store carbon in their biomass. While old trees are generally acknowledged for a long carbon residence time, there is no consensus on their contribution to carbon accumulation due to a lack of long-term individual tree data. Tree ring analyses, which use anatomical differences in the annual formation of wood for dating growth zones, are a retrospective approach that provides growth patterns of individual trees over their entire lifetime. We developed time series of diameter growth and related annual carbon accumulation for 61 trees of the species Cedrela odorata L. (Meliacea), Hymenaea courbaril L. (Fabacea) and Goupia glabra Aubl. (Goupiacea). The trees grew in unmanaged tropical wet-forests of Suriname and reached ages from 84 to 255 years. Most of the trees show positive trends of diameter growth and carbon accumulation over time. For some trees we observed fluctuating growth-periods of lower growth alternate with periods of increased growth. In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata) and 50 percent (G. glabra) of their final carbon stock. This suggests that old-growth trees in tropical forests do not only contribute to carbon stocks by long carbon resistance times, but maintain high rates of carbon accumulation at later stages of their life time.

  1. Temporal changes in tree-ring nitrogen of Pinus thunbergii trees exposed to Black-tailed Gull (Larus crassirostris) breeding colonies

    Energy Technology Data Exchange (ETDEWEB)

    Larry, Lopez C.M., E-mail: larry@iwate-u.ac.jp [United Graduate School of Agricultural Sciences, Iwate University, Morioka 020-8550 (Japan); Chitoshi, Mizota [Faculty of Agriculture, Iwate University, Morioka 020-8550 (Japan); Toshiro, Yamanaka [Division of Earth Science, Graduate School of Natural Science and Technology, Okayama University, 1-1, Naka 3-Chome, Tsushima, Okayama 700-8530 (Japan); Yoshihiro, Nobori [Faculty of Agriculture, Yamagata University, 1-23 Wakabamachi, Tsuruoka, Yamagata 997-8555 (Japan)

    2010-11-15

    Research highlights: {yields} N concentration and isotope ratio on tree-rings can be an important tool to infer past N soil conditions where trees grow. {yields} Changes in avian population on established or new breeding grounds caused by natural or anthropogenic mechanism could be inferred from the analysis shown in this paper. {yields} The property of trees to retain N concentration and N isotope characteristics is found in Pinus thunbergii. The use of other trees for similar analysis have to be determined because other species (Pinus densiflora, for example) do not have this property. - Abstract: Natural abundances of {sup 15}N/{sup 14}N ratios (commonly designated by {delta}{sup 15}N notation) of annual rings from Pinus thunbergii trees were determined after transplantation from a nursery to breeding colonies of Black-tailed Gull (Larus crassirostris) in Miyagi and Aomori and a control site in Yamagata, in northeastern Japan. Tree-rings were collected in July/August/September, 2009. Transplanting was conducted in the year 2000 in the Miyagi site, whereas there is no information about transplanting data in the Aomori and Yamagata sites. Soils associated with piscivorous (fish eating) avian colonies receive large seasonal input of organic N in the form of feces. The organic N is microbiologically transformed into inorganic N in soils, from which P. thunbergii derives its N. The resulting NH{sub 4}{sup -} and NO{sub 3}{sup -}N are characterized by distinctly heavy {delta}{sup 15}N ratios, due to coupled processes of mineralization, volatilization, nitrification and denitrification of feces. In general, total N concentration along with {delta}{sup 15}N values stored in the annual rings of P. thunbergii increased steadily after transplanting from the nursery to locations under continued avian N input. Tree-ring N content and isotopic ratios provided a reliable record of past annual available soil N caused by changes in the Black-tailed Gull population, and thus can

  2. Seasonal changes in stable carbon isotope ratios within annual growth rings of Pinus radiata

    International Nuclear Information System (INIS)

    Walcroft, A.; Silvester, W.; Whitehead, D.; Kelliher, F.

    1997-01-01

    The stable isotope composition of photosynthetically assimilated carbon (δ 13 C) is determined by the ratio of the leaf internal CO 2 concentration (c i ) to that of the ambient air (c a ), and so reflects the contribution of both stomatal conductance (g s ) and the rate of photosynthesis (A). Assimilated carbon which is subsequently laid down as wood in annual growth rings may therefore represent a time integrated record of physiological responses by the whole tree to seasonal changes in the environmental variables regulating growth. We analysed the stable carbon isotope composition of Pinus radiata wood collected from two plantation forest sites in New Zealand which differ markedly in temperature, rainfall and soil characteristics. For both sites, discs were cut from the stem of several trees near ground level and whole wood samples were taken from within individual annual growth rings over a number of years. At one site, diameter bands were installed over the 1994 - 1996 growing seasons in order to date precisely the formation of wood during that time. Trees at each site consistently showed a seasonal pattern in the stable isotope composition of wood within individual growth rings. The amplitude of seasonal δ 13 C variation at the wet and dry sites were 1-2 per thousand and 4 per thousand respectively. Mean δ 13 C values from the wet site were 3 per thousand more 13 C depleted than those from the dry site implying lower water-use efficiency (carbon assimilation per unit transpiration). A process-based, model of stomatal conductance and CO 2 assimilation was combined with a soil-water balance model to estimate the average daily leaf-level intercellular CO 2 concentration (c i ). Over two growing seasons at each site there was generally good agreement between mean canopy-level c i derived from the tree-ring δ 13 C data and modelled leaf-level c i levels. Further, the ratio of annual CO 2 assimilation to transpiration estimated by the model for each site

  3. Effect of origin conditions on the anatomical structure of the annual ring of Pinus sylvestris L. in the taiga zone

    Directory of Open Access Journals (Sweden)

    Kiсhshenko Ivan Tarasovich

    2014-11-01

    Full Text Available The studies were conducted in South Karelia (middle taiga subzone in 2006. Objects of study were the following kinds of pine forest: bilberry, cowberry and wild rosemary-bog moss ones. The investigation has shown that with the advancement of the tree in the forest canopy the annual growth ring of the trunk increases significantly. Thus, in the bilberry pine forest in the trees of the growth class I this index is higher than in the trees of the growth classes II-III and IV-V by 4 and 97 %, respectively. In the bilberry pine forest the percentage of the participation of late wood in the formation of growth ring in the dominant trees is by 6-9% less than that of the rest of the stand. The width of the early tracheid shells in the trees of the growth class I-III is by 22% more than in the overtopped ones in the bilberry pine forest. Annual ring width and latewood percentage in the pine forest of Hylocomium group is higher than in the wild rosemary – bog moss one by 41-50 and 7-35%, respectively. The maximal thickness of the late tracheid shells was observed in the cowberry pine forest (6.8-7.4 microns.

  4. Forward modeling of tree-ring data: a case study with a global network

    Science.gov (United States)

    Breitenmoser, P. D.; Frank, D.; Brönnimann, S.

    2012-04-01

    Information derived from tree-rings is one of the most powerful tools presently available for studying past climatic variability as well as identifying fundamental relationships between tree-growth and climate. Climate reconstructions are typically performed by extending linear relationships, established during the overlapping period of instrumental and climate proxy archives into the past. Such analyses, however, are limited by methodological assumptions, including stationarity and linearity of the climate-proxy relationship. We investigate climate and tree-ring data using the Vaganov-Shashkin-Lite (VS-Lite) forward model of tree-ring width formation to examine the relations among actual tree growth and climate (as inferred from the simulated chronologies) to reconstruct past climate variability. The VS-lite model has been shown to produce skill comparable to that achieved using classical dendrochronological statistical modeling techniques when applied on simulations of a network of North American tree-ring chronologies. Although the detailed mechanistic processes such as photosynthesis, storage, or cell processes are not modeled directly, the net effect of the dominating nonlinear climatic controls on tree-growth are implemented into the model by the principle of limiting factors and threshold growth response functions. The VS-lite model requires as inputs only latitude, monthly mean temperature and monthly accumulated precipitation. Hence, this simple, process-based model enables ring-width simulation at any location where monthly climate records exist. In this study, we analyse the growth response of simulated tree-rings to monthly climate conditions obtained from the 20th century reanalysis project back to 1871. These simulated tree-ring chronologies are compared to the climate-driven variability in worldwide observed tree-ring chronologies from the International Tree Ring Database. Results point toward the suitability of the relationship among actual tree

  5. Seasonal Climate Signals in Multiple Tree-Ring Parameters: A Pilot Study of Pinus ponderosa in the Columbia River Basin

    Science.gov (United States)

    Dannenberg, M.; Wise, E. K.; Keung, J. H.

    2014-12-01

    Proxy-based reconstructions of past climate have played an integral role in assessments of historical climate change, and tree-ring widths (TRW) have a long history of use in this paleoclimate research due to their annual resolution, widespread availability, and sensitivity of growth processes to variation in temperature and water availability. Increasingly, studies have shown that additional tree-ring metrics—including earlywood and latewood widths (EW and LW, respectively), maximum latewood density, and the intensity of reflected blue light from latewood (BI)—can provide additional information on seasonal climatic variability that is not present in TRW alone due to different processes that affect growth in different parts of the growing season. Studies of these additional tree-ring metrics highlight their utility in climate reconstructions, but to date they have mostly been limited to a few tree species and regions. Here, we extend the range of previous studies on alternative tree-ring metrics by evaluating the seasonal climate signals in TRW, EW, LW, and BI of Pinus ponderosa at six semiarid sites surrounding the Columbia River basin in the U.S. Pacific Northwest (PNW). Cores from each site were cross-dated and EW, LW, and TRW were measured using standard dendrochronological procedures. BI was obtained using a high-resolution flatbed scanner and CooRecorder software. To evaluate the unique climate processes and seasonalities contributing to different dendrochronological metrics, monthly temperature and precipitation from each site were obtained from the PRISM climate model and were correlated with each of the tree-ring metrics using the MATLAB program SEASCORR. We also evaluate the potential of using multiple tree-ring metrics (rather than a single proxy) in reconstructions of precipitation in the PNW. Initial results suggest that 1) tree growth at each site is water-limited but with substantial differences among the sites in the strength and seasonality of

  6. Climatic and physiological effects on leaf and tree-ring stable isotopes in California redwoods

    Science.gov (United States)

    Ambrose, A. R.; Baxter, W.; Wong, C.; Dawson, T. E.; Carroll, A.; Voelker, S.

    2016-12-01

    Variation in the stable isotope composition of organic matter can provide important information about environmental change and biological responses to it. We analyzed the stable carbon (d13C) and oxygen (d18O) isotope ratios of leaves and of the cellulose from individual tree-rings of California's two redwood species to examine how these trees have responded to environmental variation and change in both time and space. Analyses of leaf d13C for both coast redwood (Sequoia sempervirens) and giant sequoia (Sequoiadendron giganteum) from throughout their geographical ranges show a marked gradient with tree height for trees of all sizes and ages but no clear difference among species or populations. The gradient is best explained by tree response to changes in both microenvironment and physiology that are known to change with height. In contrast, leaf d18O for both species showed no clear relationship with height but very clear differences between species and populations with giant sequoia displaying a much stronger inferred leaf-level response to the higher evaporative conditions present in the Sierra Nevada mountains as compared to the coast. Both species showed population-level differences with the driest and warmest sites most distinct from all of the others. Intra-annual analyses of d13C and d18O in tree-rings over a 21-year period (1974-1994) were also used to explore how climate and tree response to climate was recorded for both species. These analyses revealed unique (local) climatic effects and response to the climate for each species and population of both redwood species. Most pronounced was a significant increase in intrinsic Water Use Efficiency (iWUE) derived from d13C data over the study period in both species, and a distinct d18O response in relation to drought (e.g. 1976/1977) and to warmer days and nights and above-average precipitation (e.g., 1982-1985). Patterns of co-variation in d13C and d18O in both species suggest that during dry and also warm

  7. Four centuries of reconstructed hydroclimatic variability for Northwestern Chihuahua, Mexico, based on tree rings

    Directory of Open Access Journals (Sweden)

    José Villanueva Díaz

    2015-03-01

    Full Text Available A Douglas-fir chronology with a length of 409 years (1600-2008 was developed for northwestern Chihuahua in Mesa de las Guacamayas, a “Natural Protected Area” known as an important nesting habitat for the thickbilled parrot (Rhynchopsitta pachyrhyncha an endangered neotropical bird. Increment cores and cross-sections from selected Douglas-fir trees (Pseudotsuga menziesii in a mixed conifer forest were obtained with an increment borer and a chain-saw. Standard dendrochronological techniques were used to process and date each one of the rings to their exact year of formation. The quality of dating of the measured series was analyzed with the COFECHA program, while biological trends not related to climate (age differences, stem-size increases, and disturbances were removed by standardization procedures in the ARSTAN program. Tree ring series of earlywood, latewood and total ring width were developed for the last four centuries. The total ring-width chronology was significantly associated (r>0.40, p=0.000 with nearby chronologies, particularly those located <200 km apart along the western slopes of the Sierra Madre Occidental (SMO observing correlations as high as 0.69 (p<0.001. Association between chronologies decreased for those sites in the state of Durango along the SMO but separated more than 200 km in straight line and also for sites in nearby borderline in the USA side. The similar climatic response among distant chronologies implies the influence of common atmospheric circulatory patterns affecting a large portion of land simultaneously. ENSO is one of the most important factors in determining inter-annual and multiannual hydroclimatic variability in northern Mexico, increasing winter-spring precipitation in its warm phase and causing extreme droughts in its cold phase.

  8. Looking for age-related growth decline in natural forests: unexpected biomass patterns from tree rings and simulated mortality

    Science.gov (United States)

    Foster, Jane R.; D'Amato, Anthony W.; Bradford, John B.

    2014-01-01

    Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality models to address two questions: first, how do assumptions about tree growth and mortality influence reconstructions of biomass growth? Second, under what circumstances does biomass production follow the model that peaks early, then declines? We integrated three stochastic mortality models with a census tree-ring data set from eight temperate forest types to reconstruct stand-level biomass increments (in Minnesota, USA). We compared growth patterns among mortality models, forest types and stands. Timing of peak biomass growth varied significantly among mortality models, peaking 20–30 years earlier when mortality was random with respect to tree growth and size, than when mortality favored slow-growing individuals. Random or u-shaped mortality (highest in small or large trees) produced peak growth 25–30 % higher than the surviving tree sample alone. Growth trends for even-aged, monospecific Pinus banksiana or Acer saccharum forests were similar to the early peak and decline expectation. However, we observed continually increasing biomass growth in older, low-productivity forests of Quercus rubra, Fraxinus nigra, and Thuja occidentalis. Tree-ring reconstructions estimated annual changes in live biomass growth and identified more diverse development patterns than previous methods. These detailed, long-term patterns of biomass development are crucial for detecting recent growth responses to global change and modeling future forest dynamics.

  9. Terahertz pulse imaging for tree-ring analysis: a preliminary study for dendrochronology applications

    International Nuclear Information System (INIS)

    Jackson, J B; Mourou, M; Whitaker, J F; Labaune, J; Mourou, G A; Duling, I N III; Williamson, S L; Lavier, C; Menu, M

    2009-01-01

    Time-domain terahertz reflection imaging is presented as a novel method of measuring otherwise inaccessible tree rings in wooden cultural heritage for the purpose of tree-ring crossdating. Axial and lateral two-dimensional terahertz images of obscured ring patterns are statistically validated with respect to their corresponding optical photographs via adapted dendrochronological methods. Results are compared to similar analysis of x-ray images of a wood specimen

  10. Flood Plain Aggradation Rates Based on Tree-Ring Growth-Suppression Dates

    Science.gov (United States)

    Friedman, J. M.

    2003-12-01

    When woody riparian plants are partially buried subsequent tree rings of the buried stems resemble those of roots. Annual rings in a buried stem are narrower and have larger vessels then those in unburied sections of the same stem. We have used this phenomenon to date flood plain sediments exposed in trenches, along two ephemeral streams in New Mexico (Rio Puerco and Chaco Wash) where the sediments are predominantly silt and very fine sand and the plants are predominantly tamarisk and willow. Cross dating down the stem allows dating of the first growth-season following burial by thick beds, and constrains the age of all stratigraphic units deposited since germination of the tree. We observed that the anatomical reaction to burial increases with bed thickness and cumulative deposition. Beds that are thicker than 30 cm can be dated to the year of the deposition event. Beds 10 to 30 cm thick can usually be dated to within several years. The period of deposition of multiple very thin beds can be constrained to the decade. Results can be improved by analyzing multiple stems from one tree and multiple trees linked together by the stratigraphy. Along our study streams, sites far from the channel tend to have moderate and relatively steady point-aggradation rates. Levees next to the channel tend to have the thickest deposits per flood and variable long-term rates, which can differ from the whole flood plain aggradation rates by several fold. Cross-sectionally averaged flood plain aggradation has been as large as a meter per decade along our study streams.

  11. Integrating tree-ring and wine data from the Palatinate (Germany)

    Science.gov (United States)

    Konter, Oliver

    2017-04-01

    Tree-ring growth of conifer trees originating from central European low mountain ranges often reveal indistinct growth-climate relationships. Temperature variations can play a crucial role, whereas water availability can also control the annual growth and become the main dominating factor. The low mountain range Pfälzerwald in the Palatinate region represents the largest contiguous forested area in Germany and features at its most eastern limitation a unique ecological setting due to its sandy soils and reduced water availability. In addition, its north-south orientation and associated lee-effects due to predominating westerlies together with altitudinal differences of more than 300 m lead to higher temperatures, lower precipitation amounts, and, as a forest management consequence, to a proportion of up to 80 % of pine trees. Despite these exceptional ecological and climatological prerequisites, calibrating tree-ring width data from 487 Pinus sylvestris core samples against regional meteorological stations (1950-2011) and gridded data (1901-2011) confirm alternating climate control mechanisms. Comparison with drought-related indices (scPDSI), combining precipitation and temperature, unfolds highest correlations with May-July conditions (r=0.34, psugar content, acidity, alcohol content, and sugar-free extracts in Riesling, Pinot Gris, Pinot Blanc, and Silvaner wines, originating from 15 wineries adjoining the forested area into the plain. Correlation of Riesling must sugar content against regional April-August temperature data reveals a highly significant signal (r=0.73, pSugar-free extract variations of Pinot Gris are significantly controlled by March-September precipitation (r=0.76, psugar content and sugar-free extract data from Riesling and Pinot Gris wine can further elucidate our understanding of longer-term climate variability in the Palatinate region.

  12. Tree-ring proxies of larch bud moth defoliation: latewood width and blue intensity are more precise than tree-ring width.

    Science.gov (United States)

    Arbellay, Estelle; Jarvis, Ingrid; Chavardès, Raphaël D; Daniels, Lori D; Stoffel, Markus

    2018-05-19

    Reconstructions of defoliation by larch bud moth (LBM, Zeiraphera diniana Gn.) based on European larch (Larix decidua Mill.) tree rings have unraveled outbreak patterns over exceptional temporal and spatial scales. In this study, we conducted tree-ring analyses on 105 increment cores of European larch from the Valais Alps, Switzerland. The well-documented history of LBM outbreaks in Valais provided a solid baseline for evaluating the LBM defoliation signal in multiple tree-ring parameters. First, we used tree-ring width measurements along with regional records of LBM outbreaks to reconstruct the occurrence of these events at two sites within the Swiss Alps. Second, we measured earlywood width, latewood width and blue intensity, and compared these parameters with tree-ring width to assess the capacity of each proxy to detect LBM defoliation. A total of six LBM outbreaks were reconstructed for the two sites between AD 1850 and 2000. Growth suppression induced by LBM was, on average, highest in latewood width (59%), followed by total ring width (54%), earlywood width (51%) and blue intensity (26%). We show that latewood width and blue intensity can improve the temporal accuracy of LBM outbreak reconstructions, as both proxies systematically detected LBM defoliation in the first year it occurred, as well as the differentiation between defoliation and non-defoliation years. This study introduces blue intensity as a promising new proxy of insect defoliation and encourages its use in conjunction with latewood width.

  13. Radiation densitometry in tree-ring analysis: a review and procedure manual

    Energy Technology Data Exchange (ETDEWEB)

    Parker, M.L.; Taylor, F.G.; Doyle, T.W.; Foster, B.E.; Cooper, C.; West, D.C.

    1985-01-01

    An x-ray densitometry of wood facility is being established by the Environmental Sciences Division, Oak Ridge Natioanl Laboratory (ORNL). The objective is to apply tree-ring data to determine whether or not there is a fertilizer effect on tree growth from increased atmospheric carbon dioxide since the beginning of the industrial era. Intra-ring width and density data, including ring-mass will be detemined from tree-ring samples collected from sites located throughout the United States and Canada. This report is designed as a guide to assist ORNL scientists in building the x-ray densitometry system. The history and development of x-ray densitometry in tree-ring research is examined and x-ray densitometry is compared with other techniques. Relative wood and tree characteristics are described as are environmental and genetic factors affecting tree growth responses. Methods in x-ray densitometry are examined in detail and the techniques used at four operating laboratories are described. Some ways that dendrochronology has been applied in dating, in wood quality, and environmental studies are presented, and a number of tree-ring studies in Canada are described. An annotated bibliography of radiation densitometry in tree-ring analysis and related subjects is included.

  14. Radiation densitometry in tree-ring analysis: a review and procedure manual

    International Nuclear Information System (INIS)

    Parker, M.L.; Taylor, F.G.; Doyle, T.W.; Foster, B.E.; Cooper, C.; West, D.C.

    1985-01-01

    An x-ray densitometry of wood facility is being established by the Environmental Sciences Division, Oak Ridge Natioanl Laboratory (ORNL). The objective is to apply tree-ring data to determine whether or not there is a fertilizer effect on tree growth from increased atmospheric carbon dioxide since the beginning of the industrial era. Intra-ring width and density data, including ring-mass will be detemined from tree-ring samples collected from sites located throughout the United States and Canada. This report is designed as a guide to assist ORNL scientists in building the x-ray densitometry system. The history and development of x-ray densitometry in tree-ring research is examined and x-ray densitometry is compared with other techniques. Relative wood and tree characteristics are described as are environmental and genetic factors affecting tree growth responses. Methods in x-ray densitometry are examined in detail and the techniques used at four operating laboratories are described. Some ways that dendrochronology has been applied in dating, in wood quality, and environmental studies are presented, and a number of tree-ring studies in Canada are described. An annotated bibliography of radiation densitometry in tree-ring analysis and related subjects is included

  15. Last millennium Northern Hemisphere summer temperatures from tree rings: Part II, spatially resolved reconstructions

    Science.gov (United States)

    Anchukaitis, Kevin J.; Wilson, Rob; Briffa, Keith R.; Büntgen, Ulf; Cook, Edward R.; D'Arrigo, Rosanne; Davi, Nicole; Esper, Jan; Frank, David; Gunnarson, Björn E.; Hegerl, Gabi; Helama, Samuli; Klesse, Stefan; Krusic, Paul J.; Linderholm, Hans W.; Myglan, Vladimir; Osborn, Timothy J.; Zhang, Peng; Rydval, Milos; Schneider, Lea; Schurer, Andrew; Wiles, Greg; Zorita, Eduardo

    2017-05-01

    Climate field reconstructions from networks of tree-ring proxy data can be used to characterize regional-scale climate changes, reveal spatial anomaly patterns associated with atmospheric circulation changes, radiative forcing, and large-scale modes of ocean-atmosphere variability, and provide spatiotemporal targets for climate model comparison and evaluation. Here we use a multiproxy network of tree-ring chronologies to reconstruct spatially resolved warm season (May-August) mean temperatures across the extratropical Northern Hemisphere (40-90°N) using Point-by-Point Regression (PPR). The resulting annual maps of temperature anomalies (750-1988 CE) reveal a consistent imprint of volcanism, with 96% of reconstructed grid points experiencing colder conditions following eruptions. Solar influences are detected at the bicentennial (de Vries) frequency, although at other time scales the influence of insolation variability is weak. Approximately 90% of reconstructed grid points show warmer temperatures during the Medieval Climate Anomaly when compared to the Little Ice Age, although the magnitude varies spatially across the hemisphere. Estimates of field reconstruction skill through time and over space can guide future temporal extension and spatial expansion of the proxy network.

  16. Reconstructions of Soil Moisture for the Upper Colorado River Basin Using Tree-Ring Chronologies

    Science.gov (United States)

    Tootle, G.; Anderson, S.; Grissino-Mayer, H.

    2012-12-01

    Soil moisture is an important factor in the global hydrologic cycle, but existing reconstructions of historic soil moisture are limited. Tree-ring chronologies (TRCs) were used to reconstruct annual soil moisture in the Upper Colorado River Basin (UCRB). Gridded soil moisture data were spatially regionalized using principal components analysis and k-nearest neighbor techniques. Moisture sensitive tree-ring chronologies in and adjacent to the UCRB were correlated with regional soil moisture and tested for temporal stability. TRCs that were positively correlated and stable for the calibration period were retained. Stepwise linear regression was applied to identify the best predictor combinations for each soil moisture region. The regressions explained 42-78% of the variability in soil moisture data. We performed reconstructions for individual soil moisture grid cells to enhance understanding of the disparity in reconstructive skill across the regions. Reconstructions that used chronologies based on ponderosa pines (Pinus ponderosa) and pinyon pines (Pinus edulis) explained increased variance in the datasets. Reconstructed soil moisture was standardized and compared with standardized reconstructed streamflow and snow water equivalent from the same region. Soil moisture reconstructions were highly correlated with streamflow and snow water equivalent reconstructions, indicating reconstructions of soil moisture in the UCRB using TRCs successfully represent hydrologic trends, including the identification of periods of prolonged drought.

  17. Climate and Streamflow Reconstruction on the São Francisco Basin, Brazil, Using Tree-Ring Data

    Science.gov (United States)

    Pereira, G. D. A.; Barbosa, A. C. M. C.; Granato-Souza, D.; Stahle, D. W.; Torbenson, M.; dos Santos, R. M.; Rodrigues Alves Delfino Barbosa, J. P.

    2017-12-01

    The São Francisco River crosses the most drought-prone region of Brazil and regional economic dynamics are dependent on the water availability in the basin. The seasonally dry forests are widely distributed in the basin, where Cedrela fissilis Vell (cedro) are frequently found. This semi-arid region provides a favorable setting where the deciduous cedro trees form well-defined semi-ring porous annual rings that can be exactly crossdated and used to build climate sensitive chronologies. Therefore, we have developed chronologies of cedro from seasonally dry forest fragments of three sites located in the middle-sector of the São Francisco River basin and south limit of the Brazilian Drought Polygon. The samples were analyzed according to standard procedures: sample preparation, ring count, crossdating and measurement of the tree rings. Dating quality was tested using the computer program COFECHA and ring-width time series where detrended and standardized to produce the final index chronology using the ARSTAN program. The results show that crossdating within and among trees from different sites demonstrate the potential to expand the spatial sampling. The tree-ring chronologies are sensitive with wet season precipitation totals (October - March), and can explain approximately 40% of the variance (1961-2015). Significant correlation was also observed with total annual discharge of the Rio São Francisco River measured at Barra (r=0.48; 1961-2015). However, the correlation disapears after 1993 (r=0.64 for 1961-1993, but r=-0.004 for 1994-2015) and we suspect that the stream gage at Barra has been impacted by human activity. Tree-ring chronologies can provide important information on climate and streamflow variability of São Francisco River, where hydrological records are often short and discontinuous. This chronology is now being extended with 150-yr old trees from the region and may be used to reconstruct climate and streamflow records back to the pre

  18. 2000 Years of Drought Variability in Inner Asia from Tree Rings

    Science.gov (United States)

    Hessl, A. E.; Pederson, N.; Anchukaitis, K. J.; Leland, C.; Byambasuren, O.; Nachin, B.; Andreu-Hayles, L.

    2015-12-01

    Understanding connections between climate, ecosystems, and society during historical and modern climatic transitions requires annual resolution records with high fidelity climate signals. In semi-arid regions, high temperatures are projected to increase the frequency, duration, and severity of droughts in coming decades. Between 1996-2014, Mongolia experienced an extended drought that coincided with a transition away from pastoralism as thousands of families lost their herds and migrated to informal urban settlements. Because Mongolia's climate is highly variable, it is difficult to place recent climatic extremes and associated social and ecological change in context without long records of climatic variability. Here we ask: how extreme was the 21st century drought in the last 2000 years? We present two 2000 year long tree-ring reconstructions of warm-season drought, derived from live and dead Siberian pine (Pinus sibirica) trees from two lava flows in central Mongolia. Trees growing on the lava today are stunted and widely spaced, occurring on microsites with little to no soil development. These trees are water-stressed and their radial growth is correlated with both soil water availability (scPDSI) and grassland productivity (Normalized Difference Vegetation Index (NDVI)). To contextualize the severity of recent droughts and to explore potential forcing factors, we compare recent drought persistence to the distribution of events in the past and perform long control runs of GFDL climate model. Our reconstructions, calibrated and validated on instrumental June-August scPDSI (1959-2009) account for >55% of the variability in the regional scPDSI when >70% of the annual rainfall occurs. Our tree-ring data combined with existing reconstructions of temperature, meteorological data, and model results suggest that the early 21st century drought was the hottest and one of the most persistent droughts in the last 2000 years. These dry conditions were occurred with

  19. Tree-ring 14C links seismic swarm to CO2 spike at Yellowstone, USA

    Science.gov (United States)

    Evans, William C.; Bergfeld, D.; McGeehin, J.P.; King, J.C.; Heasler, H.

    2010-01-01

    Mechanisms to explain swarms of shallow seismicity and inflation-deflation cycles at Yellowstone caldera (western United States) commonly invoke episodic escape of magma-derived brines or gases from the ductile zone, but no correlative changes in the surface efflux of magmatic constituents have ever been documented. Our analysis of individual growth rings in a tree core from the Mud Volcano thermal area within the caldera links a sharp ~25% drop in 14C to a local seismic swarm in 1978. The implied fivefold increase in CO2 emissions clearly associates swarm seismicity with upflow of magma-derived fluid and shows that pulses of magmatic CO2 can rapidly traverse the 5-kmthick brittle zone, even through Yellowstone's enormous hydrothermal reservoir. The 1978 event predates annual deformation surveys, but recognized connections between subsequent seismic swarms and changes in deformation suggest that CO2 might drive both processes. ?? 2010 Geological Society of America.

  20. Radiocarbon concentration in modern tree rings from Fukushima, Japan.

    Science.gov (United States)

    Xu, Sheng; Cook, Gordon T; Cresswell, Alan J; Dunbar, Elaine; Freeman, Stewart P H T; Hastie, Helen; Hou, Xiaolin; Jacobsson, Piotr; Naysmith, Philip; Sanderson, David C W

    2015-08-01

    A 30-year-old Japanese cedar (Cryptomeria japonica), collected from Iwaki, Fukushima in 2014, was analyzed for the long-lived radionuclide (14)C. Values of Δ(14)C varied from 211.7‰ in 1984 to 16.9‰ in 2013. The temporal Δ(14)C variation can be described as an exponential decline, indistinguishable from the general Northern Hemisphere Zone 2 (NH Zone 2) values in the atmosphere, until at least 1994. Values of Δ(14)C for 1999 and 2004 are slightly depleted compared with NH Zone 2 values, while from 1999 to 2013 the data suggest a clear depletion with a 2-8 ppmV additional CO2 contribution from a (14)C-free (i.e. fossil carbon) source. This change coincides with local traffic increases since two nearby expressways were opened in the 1990's. In addition, the small but visible (14)C pulse observed in the 2011 tree-ring might be caused by release from the damaged reactors during the Fukushima nuclear accident. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. The North American Drought Atlas: Tree-Ring Reconstructions of Drought Variability for Climate Modeling and Assessment

    Science.gov (United States)

    Cook, E. R.

    2007-05-01

    The North American Drought Atlas describes a detailed reconstruction of drought variability from tree rings over most of North America for the past 500-1000 years. The first version of it, produced over three years ago, was based on a network of 835 tree-ring chronologies and a 286-point grid of instrumental Palmer Drought Severity Indices (PDSI). These gridded PDSI reconstructions have been used in numerous published studies now that range from modeling fire in the American West, to the impact of drought on palaeo-Indian societies, and to the determination of the primary causes of drought over North America through climate modeling experiments. Some examples of these applications will be described to illustrate the scientific value of these large-scale reconstructions of drought. Since the development and free public release of Version 1 of the North American Drought Atlas (see http:iridl.ldeo.columbia.edu/SOURCES/.LDEO/.TRL/.NADA2004/.pdsi-atlas.html), great improvements have been made in the critical tree-ring network used to reconstruct PDSI at each grid point. This network has now been enlarged to 1743 annual tree-ring chronologies, which greatly improves the density of tree-ring records in certain parts of the grid, especially in Canada and Mexico. In addition, the number of tree-ring records that extend back before AD 1400 has been substantially increased. These developments justify the creation of Version 2 of the North American Drought Atlas. In this talk I will describe this new version of the drought atlas and some of its properties that make it a significant improvement over the previous version. The new product provides enhanced resolution of the spatial and temporal variability of prolonged drought such as the late 16th century event that impacted regions of both Mexico and the United States. I will also argue for the North American Drought Atlas being used as a template for the development of large-scale drought reconstructions in other land areas of

  2. Timing of False Ring Formation in Pinus halepensis and Arbutus unedo in Southern Italy: Outlook from an Analysis of Xylogenesis and Tree-Ring Chronologies.

    Science.gov (United States)

    De Micco, Veronica; Balzano, Angela; Čufar, Katarina; Aronne, Giovanna; Gričar, Jožica; Merela, Maks; Battipaglia, Giovanna

    2016-01-01

    Mediterranean tree rings are characterized by intra-annual density fluctuations (IADFs) due to partly climate-driven cambial activity. IADFs are used as structural signals to gain information on relations between environmental conditions and eco-physiological processes during xylogenesis, with intra-annual resolution. To reach an unbiased synchronization of the IADF position within tree rings and seasonal fluctuations in environmental conditions, it is necessary to know the timing of cambial activity and wood formation, which are species- and site-specific processes. We applied the microcoring technique to analyze xylogenesis in Pinus halepensis and Arbutus unedo. To the best of our knowledge, this is the first attempt to study xylogenesis in a hardwood species forming frequent IADFs. Both species co-occur at a site in southern Italy characterized by a Mediterranean climate. To facilitate tree-ring dating and identification of IADFs, we performed traditional dendroecological analysis. We analyzed xylogenesis during summer, which is considered a constraint for xylogenesis and a trigger for IADF formation. We followed the different phases of cell development in the current wood increment with the aim of evaluating whether and which type of IADFs were formed. We additionally analyzed the same phases again in September and in winter to verify the possible formation of IADFs in fall and whether cell production and differentiation was completed by the end of the calendar year. Both species formed the same type of IADFs (earlywood-like cells within latewood), due to temporary growth restoration triggered by rain events during the period of summer drought. At the end of the calendar year, no cells in the phases of enlargement and secondary cell wall deposition occurred. A. unedo was more sensitive than P. halepensis because IADFs were formed earlier in the season and were more frequent in the tree-ring series. The dendro-anatomical approach, combining analysis of tree-ring

  3. TIMING OF FALSE RING FORMATION IN PINUS HALEPENSIS AND ARBUTUS UNEDO IN SOUTHERN ITALY: OUTLOOK FROM AN ANALYSIS OF XYLOGENESIS AND TREE-RING CHRONOLOGIES

    Directory of Open Access Journals (Sweden)

    Veronica eDe Micco

    2016-05-01

    Full Text Available Mediterranean tree rings are characterized by Intra-Annual Density Fluctuations (IADFs due to partly climate-driven cambial activity. IADFs are used as structural signals to gain information on relations between environmental conditions and eco-physiological processes during xylogenesis, with intra-annual resolution.To reach an unbiased synchronization of the IADF position within tree rings and seasonal fluctuations in environmental conditions, it is necessary to know the timing of cambial activity and wood formation, which are species- and site-specific processes.We applied the microcoring technique to analyze xylogenesis in Pinus halepensis and Arbutus unedo. To the best of our knowledge, this is the first attempt to study xylogenesis in a hardwood species forming frequent IADFs. Both species co-occur at a site in southern Italy characterized by a Mediterranean climate. To facilitate tree-ring dating and identification of IADFs, we performed traditional dendroecological analysis. We analyzed xylogenesis during summer, which is considered a constraint for xylogenesis and a trigger for IADF formation. We followed the different phases of cell development in the current wood increment with the aim of evaluating whether and which type of IADFs were formed. We additionally analyzed the same phases again in September and in winter to verify the possible formation of IADFs in fall and whether cell production and differentiation was completed by the end of the calendar year.Both species formed the same type of IADFs (earlywood-like cells within latewood, due to temporary growth restoration triggered by rain events during the period of summer drought. At the end of the calendar year, no cells in the phases of enlargement and secondary cell wall deposition occurred. A. unedo was more sensitive than P. halepensis because IADFs were formed earlier in the season and were more frequent in the tree-ring series.The dendro-anatomical approach, combining

  4. Economics of trees versus annual crops on marginal agricultural lands

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, T.; Mohan, D.

    1982-01-01

    The results of a study conducted by the CMA in Rajasthan, selected as one of the major problem states because of its hot, arid and drought-prone character, and its present declining agricultural, livestock and fuelwood production coupled with an expansion of the area under annual crops. The present situation in Rajasthan is described and estimates made of returns from current land based enterprises (annual crops and livestock rearing) in comparison with the expected costs and returns of establishing suitable tree crops in the area. The financial and social feasibility of changing land use from annual to tree crops (while maintaining livestock production) is discussed, together with a consideration of some management and policy issues. Six tree species (Acacia tortilis, Albizzia (Albizia) lebbek, Prosopis cineraria, P. juliflora, Zizyphus species and Leucaena leucocephala) were identified as adaptable for the region and the economics of raising each over 1 felling cycle calculated. Depending on the species and cycle length, net annual returns were Rs 360-3270/ha (using a discount factor of 11%), with an expected return of Rs1680/ha if the species were allocated equally; this is considerably better than the expected returns from annual crops and standing farm trees (Rs-40 to Rs30/ha, with or without including the costs of family labor). Fifteen tables in the text and 9 in appendices give detailed breakdowns of costs and returns. 104 references.

  5. Pooled versus separate tree-ring δD measurements, and implications for reconstruction of the Arctic Oscillation in northwestern China.

    Science.gov (United States)

    Liu, Xiaohong; An, Wenling; Treydte, Kerstin; Wang, Wenzhi; Xu, Guobao; Zeng, Xiaomin; Wu, Guoju; Wang, Bo; Zhang, Xuanwen

    2015-04-01

    Stable hydrogen isotope ratios (δD) in tree rings are an attractive but still rarely explored terrestrial archive of past climatic information. Because the preparation of the cellulose nitrate for δD measurements requires more wood and a longer preparation time than preparation techniques for other isotopes in cellulose (δ18O or δ13C), it is challenging to obtain high-resolution records, especially for slow-growing trees at high elevations and in boreal regions. Here, we tested whether annually pooled samples of Qinghai spruce (Picea crassifolia Kom.) trees from northwestern China provided results similar to those derived as the mean of individual measurements of the same trees and whether the resulting chronologies recorded useful climate information. Inter-tree variability of δD was higher than that of measured ring width for the same trees. We found higher and significant coherence between pooled and mean isotope chronologies than that among the individual series. It showed a logarithmic relationship between ring mass and δD; however, accounting for the influence of ring mass on δD values only slightly improved the strength of climatic signals in the pooled records. Tree-ring δD was significantly positively correlated with the mean, maximum, and minimum temperatures during the previous winter and with maximum temperature during the current August, and significantly negatively correlated with precipitation in the previous November to January and the current July. The winter climate signal seems to dominate tree-ring δD through the influence of large-scale atmospheric circulation patterns, i.e. the Arctic Oscillation. These results will facilitate reconstruction of winter atmospheric circulation patterns over northwestern China based on a regional tree-ring δD networks. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Reconstruction of tritium release history from contaminated groundwater using tree ring analysis

    International Nuclear Information System (INIS)

    Kalin, R.M.; Murphy, C.E. Jr.; Hall, G.

    1995-01-01

    The history of tritium releases to the groundwater from buried waste was reconstructed through dendrochronology. Wood from dated tree rings was sectioned from a cross-section of a tree that was thought to tap the groundwater. Cellulose was chemically separated from the wood. The cellulose was combusted and the water of combustion collected for liquid scintillation counting. The tritium concentration in the rings rose rapidly after 1972 which was prior to the first measurements made in this area. Trends in the tritium concentration of water outcropping to the surface are similar to the trends in tritium concentration in tree rings. 14 refs., 3 figs

  7. Tree-ring analysis of winter climate variability and ENSO in Mediterranean California

    International Nuclear Information System (INIS)

    Woodhouse, C.A.; Univ. of Colorado, Boulder

    2006-01-01

    The feasibility of using tree-ring data as a proxy for regional precipitation and ENSO events in the Mediterranean region of California is explored. A transect of moisture-sensitive tree-ring sites, extending from southwestern to north-central California, documents regional patterns of winter precipitation and replicates the regional response to ENSO events in the 20. century. Proxy records of ENSO were used with the tree-ring data to examine precipitation/ENSO patterns in the 18. and 19. centuries. Results suggest some temporal and spatial variability in the regional precipitation response to ENSO over the last three centuries

  8. Paleoclimate Signals and Temperature Reconstructions for the Northeastern United States using Atlantic White Cedar Tree-Rings

    Science.gov (United States)

    Pearl, J. K.; Anchukaitis, K. J.; Pederson, N.; Donnelly, J. P.

    2016-12-01

    High-resolution paleoclimate records of the Common Era are essential for improving detection and attribution of internal and forced climate system responses. The densely populated northeastern United States is at risk from impending climate shifts as well as sea level rise. Here we present a new network of annually resolved proxy data from Atlantic white cedar trees throughout the northeastern United States. Ring width variability reflects winter through summer temperatures at inland sites north of New Jersey. Climate signals embedded in the full network are evaluated for their potential to provide reconstructions of both temperature and drought variability. We demonstrate skillful climate reconstructions for the last several centuries and the potential to use subfossil samples to extend these records over the Common Era. Our tree-ring network provides the long-term context at multidecadal and centennial time scales for the large-scale ocean-atmospheric processes that influence the climate of the region.

  9. Long-term summer sunshine/moisture stress reconstruction from tree-ring widths from Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    S. Poljanšek

    2013-01-01

    Full Text Available We present the first summer sunshine reconstruction from tree-ring data for the western part of the Balkan Peninsula. Summer sunshine is tightly connected with moisture stress in trees, because the moisture stress and therefore the width of annual tree-rings is under the influence of the direct and interactive effects of sunshine duration (temperature, precipitation, cloud cover and evapotranspiration. The reconstruction is based on a calibrated z-scored mean chronology, calculated from tree-ring width measurements from 7 representative black pine (Pinus nigra Arnold sites in Bosnia and Herzegovina (BiH. A combined regression and scaling approach was used for the reconstruction of the summer sunshine. We found a significant negative correlation (r = −0.54, p < 0.0001 with mean June–July sunshine hours from Osijek meteorological station (Croatia. The developed model was used for reconstruction of summer sunshine for the time period 1660–2010. We identified extreme summer events and compared them to available documentary historical sources of drought, volcanic eruptions and other reconstructions from the broader region. All extreme summers with low sunshine hours (1712, 1810, 1815, 1843, 1899 and 1966 are connected with volcanic eruptions.

  10. Using stable isotopes in tree rings to evaluate the impact of urban pollution on CO2 uptake by forests

    International Nuclear Information System (INIS)

    Savard, M.M.; Begin, Ch.; Marion, J.

    2004-01-01

    Contributions addressing the impact of industrial activities on tree growth are scarce; likewise, only a few studies document δ 13 C values in growth rings of natural specimens subjected to potentially toxic industrial emissions. These last studies suggest that the SO 2 emissions affect the physiology of trees and induce changes in their carbon isotope ratios. It has been reported that copper-smelter emissions reduce the C uptake of exposed trees by 35 % to 6 % relatively to unexposed trees, in growth stands located between 9 and 120 km from the smelter. In the context of the globally increasing concentrations of CO 2 in the atmosphere, what is the net impact of the large-scale annual reduction of CO 2 uptake induced by phyto-toxic pollutants? What should we expect for trees growing in regions submitted to urban diffuse pollution? It has been recently suggested on the basis of plant biomass measurements in the New York region that urban pollution can relatively reduce plant growth, but the effect is apparently greater in distant rural sites than in peri-urban and urban ones. Is this representative of numerous urban settings? If the answer to this question is yes, the pollution-effect parameter should be considered in the global annual forest C budget, particularly for the highly industrialized northern hemisphere. The specific objectives of this study are to: (1) measure the tissue increments of the stems and determine the C isotopic ratios in tree-ring cellulose of selected trees undergoing pollution stress in selected peri-urban stands; (2) present a secular time series of the CO 2 uptake by forests peripheral to a large urban region; and (3) evaluate stable isotope dendro-geochemistry as a proxy for past changes of air quality in urban and peri-urban settings. (authors)

  11. Record of the Solar Activity and of Other Geophysical Phenomenons in Tree Ring

    Science.gov (United States)

    Rigozo, Nivaor Rodolfo

    1999-01-01

    Tree ring studies are usually used to determine or verify climatic factors which prevail in a given place or region and may cause tree ring width variations. Few studies are dedicated to the geophysical phenomena which may underlie these tree ring width variations. In order to look for periodicities which may be associated to the solar activity and/or to other geophysical phenomena which may influence tree ring growth, a new interactive image analysis method to measure tree ring width was developed and is presented here. This method makes use of a computer and a high resolution flatbed scanner; a program was also developed in Interactive Data Language (IDL 5.0) to study ring digitized images and transform them into time series. The main advantage of this method is the tree ring image interactive analysis without needing complex and high cost instrumentation. Thirty-nine samples were collected: 12 from Concordia - S. C., 9 from Canela - R. S., 14 from Sao Francisco de Paula - R. S., one from Nova Petropolis - R. S., 2 from Sao Martinho da Serra - R. S. e one from Chile. Fit functions are applied to ring width time series to obtain the best long time range trend (growth rate of every tree) curves and are eliminated through a standardization process that gives the tree ring index time series from which is performed spectral analysis by maximum entropy method and iterative regression. The results obtained show periodicities close to 11 yr, 22 yr Hale solar cycles and 5.5 yr for all sampling locations 52 yr and Gleissberg cycles for Concordia - S. C. and Chile samples. El Nino events were also observed with periods around 4 e 7 yr.

  12. Relationship between carbon-14 concentrations in tree-ring cellulose and atmospheric CO2

    International Nuclear Information System (INIS)

    Yamada, Yoshimune; Yasuike, Kaeko; Komura, Kazuhisa

    2008-01-01

    Concentrations of organically-bound 14 C in the tree-ring cellulose of a Japanese Cedar (Cryptomeria japonica) grown in a rural region of Kanazawa, Ishikawa prefecture, Japan (36.5degN, 136.7degE), were measured for the ring-years from 1989 to 1998 to study relationship between 14 C concentrations in tree-ring cellulose and atmospheric CO 2 in a narrow region. An interesting result in comparing our data of tree-ring cellulose with those of atmospheric CO 2 is that the 14 C concentration in tree-ring cellulose was close to the corresponding average from mid-June to early September of 14 C concentrations in atmospheric CO 2 . Furthermore, the 14 C concentrations in tree-ring cellulose were found to be merely influenced by the drastic decrease of 14 C concentrations in atmospheric CO 2 in winter, which might be caused by air pollution from the Asian continent and additional local fossil fuel contribution. These results suggest that the 14 C concentration in tree-ring cellulose for a given growing year reflects the 14 C concentrations of atmospheric CO 2 during the warm summer months. (author)

  13. Pooled versus separate tree-ring δD measurements, and implications for reconstruction of the Arctic Oscillation in northwestern China

    International Nuclear Information System (INIS)

    Liu, Xiaohong; An, Wenling; Treydte, Kerstin; Wang, Wenzhi; Xu, Guobao; Zeng, Xiaomin; Wu, Guoju; Wang, Bo; Zhang, Xuanwen

    2015-01-01

    Stable hydrogen isotope ratios (δD) in tree rings are an attractive but still rarely explored terrestrial archive of past climatic information. Because the preparation of the cellulose nitrate for δD measurements requires more wood and a longer preparation time than preparation techniques for other isotopes in cellulose (δ 18 O or δ 13 C), it is challenging to obtain high-resolution records, especially for slow-growing trees at high elevations and in boreal regions. Here, we tested whether annually pooled samples of Qinghai spruce (Picea crassifolia Kom.) trees from northwestern China provided results similar to those derived as the mean of individual measurements of the same trees and whether the resulting chronologies recorded useful climate information. Inter-tree variability of δD was higher than that of measured ring width for the same trees. We found higher and significant coherence between pooled and mean isotope chronologies than that among the individual series. It showed a logarithmic relationship between ring mass and δD; however, accounting for the influence of ring mass on δD values only slightly improved the strength of climatic signals in the pooled records. Tree-ring δD was significantly positively correlated with the mean, maximum, and minimum temperatures during the previous winter and with maximum temperature during the current August, and significantly negatively correlated with precipitation in the previous November to January and the current July. The winter climate signal seems to dominate tree-ring δD through the influence of large-scale atmospheric circulation patterns, i.e. the Arctic Oscillation. These results will facilitate reconstruction of winter atmospheric circulation patterns over northwestern China based on a regional tree-ring δD networks. - Highlights: • The difference between mean and pooled tree-ring δD chronologies was tested. • High coherence between the chronologies for northwestern China. • Tree-ring

  14. Pooled versus separate tree-ring δD measurements, and implications for reconstruction of the Arctic Oscillation in northwestern China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaohong, E-mail: liuxh@lzb.ac.cn [State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000 (China); An, Wenling [MOE, Key Laboratory for Coast and Island Development, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210093 (China); Treydte, Kerstin [Swiss Federal Research Institute WSL, Dendro Sciences Unit, Zürcherstrasse 111, CH-8903 Birmensdorf (Switzerland); Wang, Wenzhi; Xu, Guobao; Zeng, Xiaomin; Wu, Guoju; Wang, Bo; Zhang, Xuanwen [State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2015-04-01

    Stable hydrogen isotope ratios (δD) in tree rings are an attractive but still rarely explored terrestrial archive of past climatic information. Because the preparation of the cellulose nitrate for δD measurements requires more wood and a longer preparation time than preparation techniques for other isotopes in cellulose (δ{sup 18}O or δ{sup 13}C), it is challenging to obtain high-resolution records, especially for slow-growing trees at high elevations and in boreal regions. Here, we tested whether annually pooled samples of Qinghai spruce (Picea crassifolia Kom.) trees from northwestern China provided results similar to those derived as the mean of individual measurements of the same trees and whether the resulting chronologies recorded useful climate information. Inter-tree variability of δD was higher than that of measured ring width for the same trees. We found higher and significant coherence between pooled and mean isotope chronologies than that among the individual series. It showed a logarithmic relationship between ring mass and δD; however, accounting for the influence of ring mass on δD values only slightly improved the strength of climatic signals in the pooled records. Tree-ring δD was significantly positively correlated with the mean, maximum, and minimum temperatures during the previous winter and with maximum temperature during the current August, and significantly negatively correlated with precipitation in the previous November to January and the current July. The winter climate signal seems to dominate tree-ring δD through the influence of large-scale atmospheric circulation patterns, i.e. the Arctic Oscillation. These results will facilitate reconstruction of winter atmospheric circulation patterns over northwestern China based on a regional tree-ring δD networks. - Highlights: • The difference between mean and pooled tree-ring δD chronologies was tested. • High coherence between the chronologies for northwestern China. • Tree-ring

  15. Tree-ring C-H-O isotope variability and sampling

    International Nuclear Information System (INIS)

    Leavitt, Steven W.

    2010-01-01

    In light of the proliferation of tree-ring isotope studies, the magnitude and cause of variability of tree-ring δ 13 C, δ 18 O and δ 2 H within individual trees (circumferential) and among trees at a site is examined in reference to field and laboratory sampling requirements and strategies. Within this framework, this paper provides a state-of-knowledge summary of the influence of 'juvenile' isotope effects, ageing effects, and genetic effects, as well as the interchangeability of species, choice of ring segment to analyze (whole ring, earlywood or latewood), and the option of sample pooling. The range of isotopic composition of the same ring among trees at a site is ca. 1-3 per mille for δ 13 C, 1-4 per mille δ 18 O, and 5-30 per mille for δ 2 H, whereas the circumferential variability within a tree is lower. A standard prescription for sampling and analysis does not exist because of differences in field environmental circumstances and mixed findings represented in relevant published literature. Decisions in this regard will usually be tightly constrained by goals of the study and project resources. Sampling 4-6 trees at a site while avoiding juvenile effects in rings near the pith seems to be the most commonly used methodology, and although there are some reasoned arguments for analyzing only latewood and developing separate isotope records from each tree, the existence of some contradictory findings together with efforts to reduce cost and effort have prompted alternate strategies (e.g., most years pooled with occasional analysis of rings in the sequence separately for each tree) that have produced useful results in many studies.

  16. Capturing spiral radial growth of conifers using the superellipse to model tree-ring geometric shape.

    Science.gov (United States)

    Shi, Pei-Jian; Huang, Jian-Guo; Hui, Cang; Grissino-Mayer, Henri D; Tardif, Jacques C; Zhai, Li-Hong; Wang, Fu-Sheng; Li, Bai-Lian

    2015-01-01

    Tree-rings are often assumed to approximate a circular shape when estimating forest productivity and carbon dynamics. However, tree rings are rarely, if ever, circular, thereby possibly resulting in under- or over-estimation in forest productivity and carbon sequestration. Given the crucial role played by tree ring data in assessing forest productivity and carbon storage within a context of global change, it is particularly important that mathematical models adequately render cross-sectional area increment derived from tree rings. We modeled the geometric shape of tree rings using the superellipse equation and checked its validation based on the theoretical simulation and six actual cross sections collected from three conifers. We found that the superellipse better describes the geometric shape of tree rings than the circle commonly used. We showed that a spiral growth trend exists on the radial section over time, which might be closely related to spiral grain along the longitudinal axis. The superellipse generally had higher accuracy than the circle in predicting the basal area increment, resulting in an improved estimate for the basal area. The superellipse may allow better assessing forest productivity and carbon storage in terrestrial forest ecosystems.

  17. Detecting evidence for CO2 fertilization from tree ring studies: The potential role of sampling biases

    NARCIS (Netherlands)

    Brienen, R.J.W.; Gloor, E.; Zuidema, P.A.

    2012-01-01

    Tree ring analysis allows reconstructing historical growth rates over long periods. Several studies have reported an increasing trend in ring widths, often attributed to growth stimulation by increasing atmospheric CO2 concentration. However, these trends may also have been caused by sampling

  18. Variations in Environmental Signals in Tree-Ring Indices in Trees with Different Growth Potential.

    Directory of Open Access Journals (Sweden)

    Polona Hafner

    Full Text Available We analysed two groups of Quercus robur trees, growing at nearby plots with different micro-location condition (W-wet and D-dry in the floodplain Krakovo forest, Slovenia. In the study we compared the growth response of two different tree groups to environmental variables, the potential signal stored in earlywood (EW structure and the potential difference of the information stored in carbon isotope discrimination of EW and latewood (LW. For that purpose EW and LW widths and carbon isotope discrimination for the period 1970-2008 AD were measured. EW and LW widths were measured on stained microscopic slides and chronologies were standardised using the ARSTAN program. α-cellulose was extracted from pooled EW and LW samples and homogenized samples were further analysed using an elemental analyser and IRMS. We discovered that W oaks grew significantly better over the whole analysed period. The difference between D and W oaks was significant in all analysed variables with the exception of stable carbon isotope discrimination in latewood. In W oaks, latewood widths correlated with summer (June to August climatic variables, while carbon isotope discrimination was more connected to River Krka flow during the summer. EW discrimination correlated with summer and autumn River Krka flow of the previous year, while latewood discrimination correlated with flow during the current year. In the case of D oaks, the environmental signal appears to be vague, probably due to less favourable growth conditions resulting in markedly reduced increments. Our study revealed important differences in responses to environmental factors between the two oak groups of different physiological conditions that are preconditioned by environmental stress. Environmental information stored in tree-ring features may vary, even within the same forest stand, and largely depends on the micro-environment. Our analysis confirmed our assumptions that separate EW and LW analysis of widths and

  19. Carbon-14 activity of fallout in Araucaria angustifolia annual growth rings, from Arapoti, Parana State, Brazil

    International Nuclear Information System (INIS)

    Lisi, Claudio Sergio; Pessenda, Luiz Carlos Ruiz; Tomazello Filho, Mario

    2000-01-01

    During the period of nuclear tests between 1950 and 1960, an input of artificial 14 C (fallout effect) occurred in the natural reservoirs. 14 C determinations in the Northern Hemisphere showed values of Δ 14 C up to 960 in the year of 1964. To determine the fallout 14 C activity in Brazil, wood samples from Araucaria angustifolia (Bert.) O. Kuntze, Araucariaceae, were collected in Arapoti-PR (24 deg 11 S , 49 deg 58 O ). The annual tree rings were selected by dendrochronology. The cellulose was extracted and its 14 C activity determined by liquid scintillation method. The results showed a significant increase of the Δ 14 C up to 590 in 1965, about 60% higher than the natural activity, gradually decreasing after the end of nuclear tests. These results were correlated with those obtained in the Northen Hemisphere and will be used in the studies of CO 2 mechanisms distribuition to the atmosphere and other natural reservoirs. (author)

  20. Validation of annual growth rings in freshwater mussel shells using cross dating .Can

    Science.gov (United States)

    Andrew L. Rypel; Wendell R. Haag; Robert H. Findlay

    2009-01-01

    We examined the usefulness of dendrochronological cross-dating methods for studying long-term, interannual growth patterns in freshwater mussels, including validation of annual shell ring formation. Using 13 species from three rivers, we measured increment widths between putative annual rings on shell thin sections and then removed age-related variation by...

  1. 3D multiscale micromechanical model of wood: From annual rings to microfibrils

    DEFF Research Database (Denmark)

    Qing, Hai; Mishnaevsky, Leon

    2010-01-01

    A 3D micromechanical analytical-computational model of softwood, which takes into account the wood microstructures at four scale levels, from microfibrils to annual rings, is developed. For the analysis of the effect of the annual rings structure on the properties of softwood, an improved rule-of...

  2. Conifers in cold environments synchronize maximum growth rate of tree-ring formation with day length.

    Science.gov (United States)

    Rossi, Sergio; Deslauriers, Annie; Anfodillo, Tommaso; Morin, Hubert; Saracino, Antonio; Motta, Renzo; Borghetti, Marco

    2006-01-01

    Intra-annual radial growth rates and durations in trees are reported to differ greatly in relation to species, site and environmental conditions. However, very similar dynamics of cambial activity and wood formation are observed in temperate and boreal zones. Here, we compared weekly xylem cell production and variation in stem circumference in the main northern hemisphere conifer species (genera Picea, Pinus, Abies and Larix) from 1996 to 2003. Dynamics of radial growth were modeled with a Gompertz function, defining the upper asymptote (A), x-axis placement (beta) and rate of change (kappa). A strong linear relationship was found between the constants beta and kappa for both types of analysis. The slope of the linear regression, which corresponds to the time at which maximum growth rate occurred, appeared to converge towards the summer solstice. The maximum growth rate occurred around the time of maximum day length, and not during the warmest period of the year as previously suggested. The achievements of photoperiod could act as a growth constraint or a limit after which the rate of tree-ring formation tends to decrease, thus allowing plants to safely complete secondary cell wall lignification before winter.

  3. Carbon and Oxygen Isotope Dendrochronology in Sub-Fossil Bog Oak Tree Rings - A Preliminary Study

    NARCIS (Netherlands)

    Sass, U.G.W.; Poole, I.; Wils, T.; Helle, G.; Schleser, G.H.; Bergen, van P.

    2005-01-01

    Isotope dendroclimatology is a relatively new field investigating environmental factors that control the radial growth of trees. Tree-ring series of sub-fossil bog oaks can be dated from sites across northwest Europe indicating that the environmental change(s) were regional rather than local. Bog

  4. 360 year temperature and precipitation record for the Pasco Basin derived from tree-ring data

    International Nuclear Information System (INIS)

    Cropper, J.P.; Fritts, H.C.

    1986-08-01

    Dendroclimatology, the study of past climatic variations by means of tree-ring analysis, is used to produce estimates of seasonal and annual temperature and precipitation from the 17th through 20th centuries. In this study these estimates, reconstructions, are derived in five different ways for regions that each include the Pasco Basin of south central Washington. The best of five sets of results were selected, based on the verification of the reconstructions with independent instrumental data. The reconstructed annual temperature of the Pasco Basin for the last three centuries was on the average 0.17 degrees Fahrenheit higher and had a standard deviation which was 4% larger than for the 20th century. The greatest reconstructed difference in the average temperature was in winter and the greatest reconstructed difference in the variance (standard deviation) was reconstructed in autumn. The average annual precipitation reconstructed for 1602 to 1900 was 0.32 inches higher than it has been in the 20th century. The change in average and standard deviation of reconstructed precipitation was greatest in autumn. Both the seasonal and annual reconstructions for temperature and precipitation exhibit large and persistent variations from the mean which are often most pronounced in the 17th century. Droughts were more common starting with the last half of the 17th century, with values that sometimes exceeded the 20th-century maximum amounts and duration. While there are some similarities among the four seasons and two variables, many differences between the seasonal reconstructions exist. 28 refs., 6 figs., 6 tabs

  5. A signature of cosmic-ray increase in AD 774-775 from tree rings in Japan

    Science.gov (United States)

    Miyake, Fusa; Nagaya, Kentaro; Masuda, Kimiaki; Nakamura, Toshio

    2012-06-01

    Increases in 14C concentrations in tree rings could be attributed to cosmic-ray events, as have increases in 10Be and nitrate in ice cores. The record of the past 3,000 years in the IntCal09 data set, which is a time series at 5-year intervals describing the 14C content of trees over a period of approximately 10,000 years, shows three periods during which 14C increased at a rate greater than 3‰ over 10 years. Two of these periods have been measured at high time resolution, but neither showed increases on a timescale of about 1 year (refs 11 and 12). Here we report 14C measurements in annual rings of Japanese cedar trees from AD 750 to AD 820 (the remaining period), with 1- and 2-year resolution. We find a rapid increase of about 12‰ in the 14C content from AD 774 to 775, which is about 20 times larger than the change attributed to ordinary solar modulation. When averaged over 10 years, the data are consistent with the decadal IntCal 14C data from North American and European trees. We argue that neither a solar flare nor a local supernova is likely to have been responsible.

  6. Markers inside wood : tree rings as archives of insect outbreaks, drift-sand dynamics, and spring flooding

    NARCIS (Netherlands)

    Copini, P.

    2015-01-01

    MARKERS INSIDE WOOD – TREE RINGS AS ARCHIVES OF INSECT OUTBREAKS, DRIFT-SAND DYNAMICS AND SPRING FLOODING

    Trees are long-living organisms that record ecologically relevant information in their xylem that can be accessed by dendrochronology, the study of tree rings. Specific environmental

  7. Atmospheric 14C variations derived from tree rings during the early Younger Dryas

    Science.gov (United States)

    Hua, Quan; Barbetti, Mike; Fink, David; Kaiser, Klaus Felix; Friedrich, Michael; Kromer, Bernd; Levchenko, Vladimir A.; Zoppi, Ugo; Smith, Andrew M.; Bertuch, Fiona

    2009-12-01

    Atmospheric radiocarbon variations over the Younger Dryas interval, from ˜13,000 to 11,600 cal yr BP, are of immense scientific interest because they reveal crucial information about the linkages between climate, ocean circulation and the carbon cycle. However, no direct and reliable atmospheric 14C records based on tree rings for the entire Younger Dryas have been available. In this paper, we present (1) high-precision 14C measurements on the extension of absolute tree-ring chronology from 12,400 to 12,560 cal yr BP and (2) high-precision, high-resolution atmospheric 14C record derived from a 617-yr-long tree-ring chronology of Huon pine from Tasmania, Australia, spanning the early Younger Dryas. The new tree-ring 14C records bridge the current gap in European tree-ring radiocarbon chronologies during the early Younger Dryas, linking the floating Lateglacial Pine record to the absolute tree-ring timescale. A continuous and reliable atmospheric 14C record for the past 14,000 cal yr BP including the Younger Dryas is now available. The new records indicate that the abrupt rise in atmospheric Δ 14C associated with the Younger Dryas onset occurs at ˜12,760 cal yr BP, ˜240 yrs later than that recorded in Cariaco varves, with a smaller magnitude of ˜40‰ followed by several centennial Δ 14C variations of 20-25‰. Comparing the tree-ring Δ 14C to marine-derived Δ 14C and modelled Δ 14C based on ice-core 10Be fluxes, we conclude that changes in ocean circulation were mainly responsible for the Younger Dryas onset, while a combination of changes in ocean circulation and 14C production rate were responsible for atmospheric Δ 14C variations for the remainder of the Younger Dryas.

  8. Precipitation variability inferred from the annual growth and isotopic composition of tropical trees

    Science.gov (United States)

    Ballantyne, A. P.; Baker, P. A.; Chambers, J. Q.; Villalba, R.

    2005-12-01

    Here we demonstrate that annual growth and isotopic ratios in tropical trees are responsive to seasonal and annual precipitation variability. We identify several regions of tropical South America characterized by significant relationships between oxygen isotopic ratios (δ 18O) in precipitation and precipitation amount (r = -0.82). Many of these regions are also sensitive to inter-annual variability in the South American Monsoon modulated by the El Niño Southern Oscillation (ENSO). The effectiveness of δ 18O and annual growth of tropical trees as a precipitation proxy is validated by high-resolution sampling of a Tachigali vermelho tree growing near Manaus, Brazil (3.1° S, 60.0° S). Growth in Tachigali spp. was highly correlated with both precipitation and cellulose δ 18O (r = 0.60) and precipitation amount was significantly correlated with δ 18O at a lag of approximately one month (r = 0.56). We also report a multi-proxy record spanning 180 years from Cedrela odorata growing in the Peruvian Amazon near Puerto Maldonado (12.6° S, 69.2° W) revealing a significant relationship between cellulose and monsoon precipitation over the region (r = -0.33). A 150-year record obtained from Polylepis tarapacana growing at Volcan Granada in Northern Argentina (22.0° S, 66.0° W) is also reported with a significant relationship between local monsoon precipitation and a regionally derived ring width index (r = 0.38). Although no significant relationship was revealed between cellulose δ 18O and precipitation in this taxa at this location, separate radii within the same tree revealed a significantly coherent δ 18O signal (r = 0.38). We compared our proxy chronologies with monsoon precipitation reanalysis data for tropical South America, which revealed key features of the South American Monsoon and their sensitivity to ENSO variability.

  9. A stable lead isotopic investigation of the use of sycamore tree rings as a historical biomonitor of environmental lead contamination

    International Nuclear Information System (INIS)

    Patrick, Gavin J.; Farmer, John G.

    2006-01-01

    transect. Overall the data suggest that sycamore tree-ring analysis is an unsuitable method for obtaining records of historical lead deposition in areas with no large local lead input, although it can reveal some information about the temporal and spatial influence of point source emitters. The unsuitability probably arises from the number of active annual rings in a single year, the post-uptake radial translocation of elements, the relative importance of the different routes of uptake, and the soil depth(s) from which trees draw nutrients

  10. Mass movements and tree rings: A guide to dendrogeomorphic field sampling and dating

    Science.gov (United States)

    Stoffel, Markus; Butler, David R.; Corona, Christophe

    2013-10-01

    Trees affected by mass movements record the evidence of geomorphic disturbance in the growth-ring series, and thereby provide a precise geochronological tool for the reconstruction of past activity of mass movement. The identification of past activity of processes was typically based on the presence of growth anomalies in affected trees and focused on the presence of scars, tilted or buried trunks, as well as on apex decapitation. For the analyses and interpretation of disturbances in tree-ring records, in contrast, clear guidelines have not been established, with largely differing or no thresholds used to distinguish signal from noise. At the same time, processes with a large spatial footprint (e.g., snow avalanches, landslides, or floods) will likely leave growth anomalies in a large number of trees, whereas a falling rock would only cause scars in one or a few trees along its trajectory.

  11. Tree-rings and climate: Implications for Great Basin paleoenvironmental studies

    International Nuclear Information System (INIS)

    Graybill, D.A.; Rose, M.R.; Nials, F.L.

    1994-01-01

    The Quaternary Sciences Center of the Desert Research Institute is currently conducting a multi-phased study of floral, faunal, and geomorphic response to long- and short-term climate change and extremes in assessing Yucca Mountain's suitability as a high-level nuclear waste repository. Preliminary results of these studies indicate synchronous responses in late Holocene tree-ring, palynology and geomorphic records. A tree-ring chronology for paleoclimatic reconstruction is developed by collection of multiple cores from 20-60 living trees and a similar number of dead trees in a climate-sensitive location. Samples are cross-dated and every growth layer in each specimen is measured to the nearest .001 mm. The measured ring width series potentially contain a variety of climatic, biological, and anthropogenic signals. Each ring width series is subjected to a numerical standarization procedure that removes an age-related biological growth trend, reduces endogeneous and exogenous stand disturbance factors, and maximizes any climatic signal that is present. Each of these empirically defined components can be graphically portrayed and subjected to further analyses. The geophysical signal analysis techniques involved in the standarized protocol are well-documented and established. The final result is a tree-ring chronology that represents regional paleoclimatic variability over the time represented by the sample population

  12. Long-term tree growth rate, water use efficiency, and tree ring nitrogen isotope composition of Pinus massoniana L. in response to global climate change and local nitrogen deposition in Southern China

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Fangfang [Chinese Academy of Sciences, Guangzhou (China). South China Botanical Garden; Graduate Univ. of Chinese Academy of Sciences, Beijing (China); Griffith Univ., Nathan, QLD (Australia). Environmental Future Centre; Kuang, Yuanwen; Wen, Dazhi [Chinese Academy of Sciences, Guangzhou (China). South China Botanical Garden; Chinese Academy of Sciences, Guangzhou (China). Pearl River Delta Research Centre of Environmental Pollution and Control; Xu, Zhihong [Griffith Univ., Nathan, QLD (Australia). Environmental Future Centre; Li, Jianli; Zuo, Weidong [Agriculture and Forestry Technology Extension Centre, Nanhai District, Guangdong (China); Hou, Enqing [Chinese Academy of Sciences, Guangzhou (China). South China Botanical Garden; Graduate Univ. of Chinese Academy of Sciences, Beijing (China)

    2010-12-15

    We aimed to investigate long-term tree growth rates, water use efficiencies (WUE), and tree ring nitrogen (N) isotope compositions ({delta}{sup 15}N) of Masson pine (Pinus massoniana L.) in response to global climate change and local N deposition in Southern China. Tree annual growth rings of Masson pine were collected from four forest sites, viz. South China Botanical Garden (SBG), Xi Qiao Shan (XQS) Forest Park, Ding Hu Shan (DHS) Natural Reserve, and Nan Kun Shan (NKS) Natural Reserve in Southern China. The mean annual basal area increment (BAI), WUE, and {delta}{sup 15}N at every 5-year intervals of Masson pine during the last 50 years were determined. Regression analyses were used to quantify the relationships of BAI and WUE with atmospheric carbon dioxide concentration ([CO{sub 2}]), temperature, rainfall, and tree ring elemental concentrations at the four study sites. Tree BAI showed a quadratic relationship with rising [CO{sub 2}]. The tipping points of [CO{sub 2}] for BAI, the peaks of BAI when the critical [CO{sub 2}] was reached, occurred earlier at the sites of SBG, XQS, and DHS which were exposed to higher temperature, N deposition, and lower mineral nutrient availability, as compared with the tipping points of [CO{sub 2}] for BAI at the site of NKS which had higher rainfall, lower temperature, and better nutritional status. The average tipping point of [CO{sub 2}] at the four sites for the BAI response curves was 356 ppm, after which, the BAI would be expected to decrease quadratically with rising [CO{sub 2}]. The multiple regressions of BAI confirmed the relationships of long-term tree growth rate with rainfall, tree WUE, and nutrients and {delta}{sup 15}N in tree rings. Nonlinear relationships between BAI and tree ring {delta}{sup 15}N at DHS and negatively linear one at NKS reflected the fertilization effect of N deposition on tree growth rate initially, but this effect peaked or became negative once the forest approached or passed the N saturation

  13. Tree Ring Analyses Unlock a Century of Hydroclimatic Variability Across the Himalayas

    Science.gov (United States)

    Brunello, C. F.; Andermann, C.; Helle, G.; Comiti, F.; Tonon, G.; Hovius, N.

    2017-12-01

    Climate change has altered precipitation patterns and impacted the spatio-temporal distribution and availability of water in high mountain environments. For example, intensification of the Indian Summer Monsoon (ISM) increases the potential for moisture laden air to breach the Himalayan orographic barrier and penetrate into the arid, elevated southern Tibetan Plateau, with geomorphological and hydrological consequences. Such trends should be considered against a solid background, but a consistent record of centennial monsoon dynamics in the trans-Himalayan region has never been developed. Instrumental data are sparse and only cover a limited time period as well as remotely sensed information. Meanwhile, models have major systematic bias and substantial uncertainty in reproducing ISM interannual variability. In this context, hydro-climatic proxies, such as oxygen stable isotope ratios in cellulose of tree rings, are a valuable source of data, especially because isotope mass spectroscopy can unlock yearly resolved information by tracing the isotopic signature (18O) stored within each growth ring. Here we present three centennial records of monsoon dynamics, along a latitudinal transect, spanning a pronounced precipitation gradient across the Himalayan orogen. Three sites were selected along the Kali Gandaki valley in the central Himalayas (Nepal), this valley connects the wet, monsoon dominated Gangetic plain with the arid Tibetan Plateau. Our transect covers the sensitive northern end of the precipitation gradient, located in the upper part of the catchment. Our results show that inter-annual variation of monsoon strength can be reconstructed by tree ring δ18O. The inferred monsoon dynamics are compared against independent constraints on precipitation, snow cover and river discharge. Different water sources contribute disproportionally at the three sites, reflecting spatial and temporal shifts of the westerlies and the Indian summer monsoon. These two dominant

  14. Tree rings as monitors of heavy metal air pollution histories

    International Nuclear Information System (INIS)

    Kennedy, G.; Bergeron, S.

    1991-01-01

    The potential of five species of trees as historical monitors of heavy metal air pollution has been investigated. The study was carried out at a site 2 km from an industrial complex including several metal refineries. Using neutron activation, heavy metal concentrations were measured in the xylem as a function of the year of wood formation. The manganese concentrations were by far the highest. In maple trees the high natural level of this essential trace element masked any increases due to pollution. In ash and cedar increased Mn concentrations were found, relative to control trees, but there is evidence for radial translocation. In hemlock the time variations of the average Mn concentrations followed the production rates of the refineries but large variations among individual trees were observed. Hemlock was estimated to accumulate up to 0.3% of the atmospheric Mn input. (author) 13 refs.; 3 figs

  15. Shedding light on tree growth : ring analysis of juvenile tropical trees

    NARCIS (Netherlands)

    Soliz Gamboa, C.C.

    2010-01-01

    In the understory of tropical forests light is believed to be the main limiting growth factor for the newly established trees. Trees growing in shade of the understory may experience periods of slow radial growth. It is expected that gaps created by tree or branch fall will provoke tree growth

  16. Using Tree-Ring Data, Research, and Expeditions as an Accessible, Hands-on "Bridge" into Climate Studies for Diverse Audiences

    Science.gov (United States)

    Davi, N. K.; Wattenberg, F.; Pringle, P. T.; Tanenbaum, J.; O'Brien, A.; Greidanus, I.; Perry, M.

    2012-12-01

    Tree-ring research provides an engaging, intuitive, and relevant entryway into understanding both climate-change and environmental research, as well as the process of science from inspiration, to fieldwork, to analysis, to publishing and communicating. The basic premise of dendrochronology is that annual rings reflect environmental conditions year-by-year and that by studying long-lived trees we can learn about past environments and climates for hundreds-to-thousands of years in the past. Conceptually, this makes tree-ring studies accessible to students and faculty for a number of reasons. First, in order to collect their data, dendrochronologists often launch expeditions to stunningly picturesque and remote places in search of long-lived, climate sensitive trees. Scientist exciting stories and images from the field can be leveraged to connect students to the study and the data. Second, tree-rings can be more easily explained as a proxy for climate than other methods (ice cores, carbon-isotope ratios, etc.), and most people have prior-knowledge about trees and annual growth rings. It is even possible, for example, for non-expert audiences to see climate variability through time with the naked eye by looking at climate sensitive tree cores. Third, tree-rings are interdisciplinary and illustrate the interplay between the mathematical sciences, the biological sciences, and the geosciences—that is, they show that the biosphere is a fundamental component of the Earth system. Here, we will present several projects have been initiated for a range of audiences, including; elementary school, where 5th graders visited a local forest to collect samples and apply their samples and what they learned to math and science classes. 5th grade students also leaned how to use Climate Explorer (KNMI), an online tool that allows scientist and students the opportunity to access and visualize global climate data within a few clicks. Geared to 2 and 4 year colleges, we are also

  17. {delta}{sup 13}C of Tree-Ring Lignin as an Indirect Measure of Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, I. [CSIR Environmentek, Quaternary Dating Research Unit (South Africa)], E-mail: i.robertson@swansea.ac.uk; Loader, N. J.; McCarroll, D. [University of Wales Swansea, Department of Geography (United Kingdom); Carter, A. H. C. [University of Cambridge, Godwin Institute for Quaternary Research (United Kingdom); Cheng, L.; Leavitt, S. W. [University of Arizona, Laboratory of Tree-Ring Research (United States)

    2004-06-15

    High-resolution paleoclimatic data are an essential requirement for testing numerical models of climate change and the global carbon cycle. If the long tree-ring chronologies, originally established for the purpose of dendrochronology, are to be fully exploited as an indirect measure of past climatic variability, additional techniques are required to obtain this information. The determination of the {delta}{sup 13}C value of tree-ring cellulose has been used successfully to reconstruct past climates. However, under both aerobic and anaerobic conditions, the polysaccharide components of vascular plants (mainly cellulose and hemicelluloses) are more prone to rapid degradation than lignin. This has serious implications for the use of carbon isotope values of tree-ring cellulose as an indirect measure of past climates. An absolutely dated ring-width chronology was established for oaks (Quercus robur L.) growing at Sandringham Park in eastern England. Carbon isotope values were determined on {alpha}-cellulose and 'Klason' lignin isolated from annual latewood samples over the period AD 1895-1999. The carbon isotope values of earlywood lignin are correlated with the latewood carbon isotope values of the previous year, supporting the theory that some of the carbon utilised in earlywood synthesis is assimilated in the previous year. The high-frequency variance in the carbon isotope indices of latewood lignin and cellulose is highly correlated with combined July and August environmental variables, indicating that they were formed at similar times. There was no evidence of secondary lignification. These results demonstrate that the determination of carbon isotope values of latewood lignin offers the potential to obtain unambiguous proxy climatic data covering several millennia.

  18. Patterns of Storage, Synthesis and Changing Light Levels Revealed by Carbon Isotope Microsampling within Eocene Metasequoia Tree Rings

    Science.gov (United States)

    Jahren, H.; Sternberg, L.

    2005-12-01

    Fossil tree rings from Axel Heiberg Island were microanalyzed for δ13C value in order to assess patterns of tree growth and carbon storage within the Middle Eocene (~45 Ma) Arctic paleoenvironment. Wood from four Metasequoia-type individuals was subsampled for analysis: each individual fossil consisted of between 4 and 10 large (~1 cm thick) consecutive tree rings. One of the fossils displayed an obvious concentric pattern, allowing for the determination of the direction of growth with isotopic pattern. Each ring was divided into ~1 mm thick subsamples, resulting in 5-10 δ13C value determinations per period of ring growth (i.e., growing season). All rings revealed a distinct pattern that was characteristic across growing seasons and across individual fossils. Early in the season, δ13C was at its highest value but descended systematically and sharply to its lowest value at the end of the growing season. Total decrease ranged between 3 and 5 ‰ over the course of each growing season. Identical patterns were observed in the δ13C value of alpha-cellulose isolated from each subsample, indicating that the trends observed did not represent changing levels of secondary metabolites, but rather a seasonal adjustment in the bulk source of carbon used during biosynthesis. Our results are consistent with the following annual pattern of wood synthesis 1.) complete dependence on the mobilization of stored carbon compounds early in the growing season; 2.) systematically increasing use of actively-acquired photosynthate during the growing season; 3.) complete reliance on active photosynthate by the end of the growing season. An additional and significant source of 13C discrimination is declining light levels late in the growing season, and likely contributes to the extreme pattern of δ13C decrease seen across each ring. Our results mimic those seen from modern broadleaf deciduous trees (Helle & Schlesser 2004), but differ from those seen in modern conifers (Barbour et al 2002

  19. {sup 14}C AMS measurements in tree rings to estimate local fossil CO{sub 2} in Bosco Fontana forest (Mantova, Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Capano, Manuela, E-mail: capanomanuela@tiscali.i [CIRCE, Dipartimento di Scienze Ambientali, Seconda Universita di Napoli, and INNOVA, Via Vivaldi, 43 81100 Caserta (Italy); Marzaioli, Fabio; Sirignano, Carmina; Altieri, Simona; Lubritto, Carmine; D' Onofrio, Antonio; Terrasi, Filippo [CIRCE, Dipartimento di Scienze Ambientali, Seconda Universita di Napoli, and INNOVA, Via Vivaldi, 43 81100 Caserta (Italy)

    2010-04-15

    Radiocarbon concentration in atmosphere changes overtime due to anthropogenic and natural factors. Species growth preserves the local atmospheric radiocarbon signature over their life span in the annual tree rings and make it possible to use tree rings for the monitoring of changes in fossil-fuel emissions due to an increase of traffic exhaust, during the last decades. In this paper, the CIRCE AMS system has been used to measure the {sup 14}C concentration in tree rings of plants grown near an industrial area and a very busy State Road, in a forest in north Italy. Preliminary results related to tree rings of several years of plants respectively near and far the emitting sources are displayed, in order to estimate the local pollution effect. It is possible to find a dilution in years 2000 and 2006 in both the trees analysed, but not enough data have been analysed yet in order to distinguish the fossil dilution derived from the street vehicular traffic or that from the industries.

  20. The longevity of broadleaf deciduous trees in Northern Hemisphere temperate forests: insights from tree-ring series

    Directory of Open Access Journals (Sweden)

    Alfredo eDi Filippo

    2015-05-01

    Full Text Available Understanding the factors controlling the expression of longevity in trees is still an outstanding challenge for tree biologists and forest ecologists. We gathered tree-ring data and literature for broadleaf deciduous (BD temperate trees growing in closed-canopy old-growth forests in the Northern Hemisphere to explore the role of geographic patterns, climate variability, and growth rates on longevity. Our pan-continental analysis, covering 32 species from 12 genera, showed that 300-400 years can be considered a baseline threshold for maximum tree lifespan in many temperate deciduous forests. Maximum age varies greatly in relation to environmental features, even within the same species. Tree longevity is generally promoted by reduced growth rates across large genetic differences and environmental gradients. We argue that slower growth rates, and the associated smaller size, provide trees with an advantage against biotic and abiotic disturbance agents, supporting the idea that size, not age, is the main constraint to tree longevity. The oldest trees were living most of their life in subordinate canopy conditions and/or within primary forests in cool temperate environments and outside major storm tracks. Very old trees are thus characterized by slow growth and often live in forests with harsh site conditions and infrequent disturbance events that kill much of the trees. Temperature inversely controls the expression of longevity in mesophilous species (Fagus spp., but its role in Quercus spp. is more complex and warrants further research in disturbance ecology. Biological, ecological and historical drivers must be considered to understand the constraints imposed to longevity within different forest landscapes.

  1. A stable-isotope tree-ring timescale of the Late Glacial/Holocene boundary

    International Nuclear Information System (INIS)

    Becker, Bernd; Kromer, Bernd; Trimborn, Peter

    1991-01-01

    Late Glacial and Holocene tree-ring chronologies, like deep-sea sediments or polar ice cores, contain information about past environments. Changes in tree-ring growth rates can be related to past climate anomalies and changes in the isotope composition of tree-ring cellulose reflect changes in the composition of the atmosphere and the hydrosphere. We have established a 9,928-year absolutely dated dendrochronological record of Holocene oak (Quercus robur, Quercus petraea)-and a 1,604-year floating Late Glacial and Early Holocene chronology of pine (Pinus sylvestris) from subfossil tree remnants deposited in alluvial terraces of south central European rivers. The pine sequence provides records of dendro-dated 14 C, 13 C and 2 H patterns for the late Younger Dryas and the entire Preboreal (10,100-9,000 yr BP). Through the use of dendrochronology, radiocarbon age calibration and stable isotope analysis, we suggest that the Late Glacial/Holocene transition may be identified and dated by 13 C and 2 H tree-ring chronologies. (author)

  2. Missing Rings in Pinus halepensis – The Missing Link to Relate the Tree-Ring Record to Extreme Climatic Events

    Science.gov (United States)

    Novak, Klemen; de Luis, Martin; Saz, Miguel A.; Longares, Luis A.; Serrano-Notivoli, Roberto; Raventós, Josep; Čufar, Katarina; Gričar, Jožica; Di Filippo, Alfredo; Piovesan, Gianluca; Rathgeber, Cyrille B. K.; Papadopoulos, Andreas; Smith, Kevin T.

    2016-01-01

    Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, this division may occur throughout almost the entire year. Alternatively, cell division may cease during relatively cool and dry winters, only to resume in the same calendar year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR). A dendrochronological network of Pinus halepensis was used to determine the relationship of MR to ECE. The network consisted of 113 sites, 1,509 trees, 2,593 cores, and 225,428 tree rings throughout the distribution range of the species. A total of 4,150 MR were identified. Binomial logistic regression analysis determined that MR frequency increased with increased cambial age. Spatial analysis indicated that the geographic areas of south-eastern Spain and northern Algeria contained the greatest frequency of MR. Dendroclimatic regression analysis indicated a non-linear relationship of MR to total monthly precipitation and mean temperature. MR are strongly associated with the combination of monthly mean temperature from previous October till current February and total precipitation from previous September till current May. They are likely to occur with total precipitation lower than 50 mm and temperatures higher than 5°C. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a complication for dendrochronology, MR formation is a fundamental response of trees

  3. Missing Rings in Pinus halepensis - The Missing Link to Relate the Tree-Ring Record to Extreme Climatic Events.

    Science.gov (United States)

    Novak, Klemen; de Luis, Martin; Saz, Miguel A; Longares, Luis A; Serrano-Notivoli, Roberto; Raventós, Josep; Čufar, Katarina; Gričar, Jožica; Di Filippo, Alfredo; Piovesan, Gianluca; Rathgeber, Cyrille B K; Papadopoulos, Andreas; Smith, Kevin T

    2016-01-01

    Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, this division may occur throughout almost the entire year. Alternatively, cell division may cease during relatively cool and dry winters, only to resume in the same calendar year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR). A dendrochronological network of Pinus halepensis was used to determine the relationship of MR to ECE. The network consisted of 113 sites, 1,509 trees, 2,593 cores, and 225,428 tree rings throughout the distribution range of the species. A total of 4,150 MR were identified. Binomial logistic regression analysis determined that MR frequency increased with increased cambial age. Spatial analysis indicated that the geographic areas of south-eastern Spain and northern Algeria contained the greatest frequency of MR. Dendroclimatic regression analysis indicated a non-linear relationship of MR to total monthly precipitation and mean temperature. MR are strongly associated with the combination of monthly mean temperature from previous October till current February and total precipitation from previous September till current May. They are likely to occur with total precipitation lower than 50 mm and temperatures higher than 5°C. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a complication for dendrochronology, MR formation is a fundamental response of trees

  4. Missing rings in Pinus halepensis – the missing link to relate the tree-ring record to extreme climatic events

    Directory of Open Access Journals (Sweden)

    Klemen eNovak

    2016-05-01

    Full Text Available Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE. These conditions are associated with decreased growth of trees and their increased vulnerability to pests and diseases. The anatomy of tree rings is responsive to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, cambial cell division may occur throughout almost the entire year. Alternatively, cell division may stop during relatively cool and dry winters, only to resume in the same year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR, which can link tree-ring anatomy to the occurrence of extreme events. A dendrochronological network of Pinus halepensis, a widespread tree species in the Mediterranean basin, was used to determine the relationship of MR to ECE. The network consisted of 113 sites throughout its distribution range. Binomial logistic regression analysis of 2595 MR series determined that MR increased in frequency with increased cambial age. Spatial analysis indicated that the geographic areas of southeastern Spain and northern Algeria contained the greatest frequency of MR. Further regression analysis indicated that the relationship of MR to total monthly precipitation and mean temperature was non-linear. In this first determination of climatic influences on MR, the formation of MR was most strongly associated with the combination of monthly mean temperature above 10°C from previous October till current February and total precipitation below 50 mm from previous September till current May. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a

  5. The investigation of solar activity signals by analyzing of tree ring chronological scales

    Science.gov (United States)

    Nickiforov, M. G.

    2017-07-01

    The present study examines the ability of detecting short-cycles and global minima of solar activity by analyzing dendrochronologies. Starting with the study of Douglass, which was devoted to the question of climatic cycles and the growth of trees, it is believed that the analysis of dendrochronologies allows to detect the cycle of Wolf-Schwabe. According to his results, the cycle was absent during Maunder's minimum and appeared after its completion. Having checked Douglass's conclusions by using 10 dendrochronologies of yellow pines from Arizona, which cover the time period from 1600 to 1900, we have come to the opposite results. The verification shows that: a) none of the considered dendroscale allows to detect an 11-year cycle; 2) the behaviour of a short peroid-signal does not undergo significant changes before, during or after Maunder's minimum. A similar attempt to detect global minima of solar activity by using five dendrochronologies from different areas has not led to positive results. On the one hand, the signal of global extremum is not always recorded in dendrochronology, on the other hand, the deep depression of annual rings allows to suppose the existence of a global minimum of solar activity, which is actually absent.

  6. Stable isotope investigations from tree rings (Betula pubescens) in Northern Iceland

    International Nuclear Information System (INIS)

    Bertler, N.A.N.; Rose, J.J.; Mattey, D.P.; Brownlees, M.; Stoetter, J.E.

    1999-01-01

    Stable isotope investigations from recent trees (Betual pubescens) from two different locations in Northern Iceland have been carried out to examine applicability for paleoclimatic research. The aim was to correlate oxygen and carbon isotope data of annual and three year resolution derived from individual rings with meteorological data, in order to establish a calibration function for fossil wood samples. A precise dendrochronological record has been established for all cores to permit a direct comparison between different data sets. The material used for the isotopic analysis is pure α-cellulose. The oxygen and carbon ratios were measured using a new technique, employing CO with continuous flow mass spectrometry. As this method does not allow a simultaneous measurements of the carbon ratios, the δ 13 C values have been analysed separately, using CO 2 . Both methods demonstrated their reliability through high precision and accuracy in the values for the measured standards. However there is little confidence in the sample data, as they suffer from poor precision and non-consistency

  7. Tree ring evidence for limited direct CO2 fertilization of forests over the 20th century

    Science.gov (United States)

    Gedalof, Ze'ev; Berg, Aaron A.

    2010-09-01

    The effect that rising atmospheric CO2 levels will have on forest productivity and water use efficiency remains uncertain, yet it has critical implications for future rates of carbon sequestration and forest distributions. Efforts to understand the effect that rising CO2 will have on forests are largely based on growth chamber studies of seedlings, and the relatively small number of FACE sites. Inferences from these studies are limited by their generally short durations, artificial growing conditions, unnatural step-increases in CO2 concentrations, and poor replication. Here we analyze the global record of annual radial tree growth, derived from the International Tree ring Data Bank (ITRDB), for evidence of increasing growth rates that cannot be explained by climatic change alone, and for evidence of decreasing sensitivity to drought. We find that approximately 20 percent of sites globally exhibit increasing trends in growth that cannot be attributed to climatic causes, nitrogen deposition, elevation, or latitude, which we attribute to a direct CO2 fertilization effect. No differences were found between species in their likelihood to exhibit growth increases attributable to CO2 fertilization, although Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa), the two most commonly sampled species in the ITRDB, exhibit a CO2 fertilization signal at frequencies very near their upper and lower confidence limits respectively. Overall these results suggest that CO2 fertilization of forests will not counteract emissions or slow warming in any substantial fashion, but do suggest that future forest dynamics may differ from those seen today depending on site conditions and individual species' responses to elevated CO2.

  8. Magnetic record associated with tree ring density: Possible climate proxy

    Czech Academy of Sciences Publication Activity Database

    Kletetschka, Günther; Pruner, Petr; Venhodová, Daniela; Kadlec, Jaroslav

    2007-01-01

    Roč. 8, - (2007), s. 1-11 ISSN 1467-4866 Institutional research plan: CEZ:AV0Z3013912 Keywords : palaeo-climatic indicator * sequoia tree * magnetic properties Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.842, year: 2007

  9. Detecting instabilities in tree-ring proxy calibration

    Directory of Open Access Journals (Sweden)

    H. Visser

    2010-06-01

    Full Text Available Evidence has been found for reduced sensitivity of tree growth to temperature in a number of forests at high northern latitudes and alpine locations. Furthermore, at some of these sites, emergent subpopulations of trees show negative growth trends with rising temperature. These findings are typically referred to as the "Divergence Problem" (DP. Given the high relevance of paleoclimatic reconstructions for policy-related studies, it is important for dendrochronologists to address this issue of potential model uncertainties associated with the DP. Here we address this issue by proposing a calibration technique, termed "stochastic response function" (SRF, which allows the presence or absence of any instabilities in growth response of trees (or any other climate proxy to their calibration target to be visualized and detected. Since this framework estimates confidence limits and subsequently provides statistical significance tests, the approach is also very well suited for proxy screening prior to the generation of a climate-reconstruction network.

    Two examples of tree growth/climate relationships are provided, one from the North American Arctic treeline and the other from the upper treeline in the European Alps. Instabilities were found to be present where stabilities were reported in the literature, and vice versa, stabilities were found where instabilities were reported. We advise to apply SRFs in future proxy-screening schemes, next to the use of correlations and RE/CE statistics. It will improve the strength of reconstruction hindcasts.

  10. Tracing footprints of environmental events in tree ring chemistry using neutron activation analysis

    Science.gov (United States)

    Sahin, Dagistan

    The aim of this study is to identify environmental effects on tree-ring chemistry. It is known that industrial pollution, volcanic eruptions, dust storms, acid rain and similar events can cause substantial changes in soil chemistry. Establishing whether a particular group of trees is sensitive to these changes in soil environment and registers them in the elemental chemistry of contemporary growth rings is the over-riding goal of any Dendrochemistry research. In this study, elemental concentrations were measured in tree-ring samples of absolutely dated eleven modern forest trees, grown in the Mediterranean region, Turkey, collected and dated by the Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology laboratory at Cornell University. Correlations between measured elemental concentrations in the tree-ring samples were analyzed using statistical tests to answer two questions. Does the current concentration of a particular element depend on any other element within the tree? And, are there any elements showing correlated abnormal concentration changes across the majority of the trees? Based on the detailed analysis results, the low mobility of sodium and bromine, positive correlations between calcium, zinc and manganese, positive correlations between trace elements lanthanum, samarium, antimony, and gold within tree-rings were recognized. Moreover, zinc, lanthanum, samarium and bromine showed strong, positive correlations among the trees and were identified as possible environmental signature elements. New Dendrochemistry information found in this study would be also useful in explaining tree physiology and elemental chemistry in Pinus nigra species grown in Turkey. Elemental concentrations in tree-ring samples were measured using Neutron Activation Analysis (NAA) at the Pennsylvania State University Radiation Science and Engineering Center (RSEC). Through this study, advanced methodologies for methodological, computational and

  11. Sap Flux Scaled Transpiration in Ring-porous Tree Species: Assumptions, Pitfalls and Calibration

    Science.gov (United States)

    Bush, S. E.; Hultine, K. R.; Ehleringer, J. R.

    2008-12-01

    Thermal dissipation probes for measuring sap flow (Granier-type) at the whole tree and stand level are routinely used in forest ecology and site water balance studies. While the original empirical relationship used to calculate sap flow was reported as independent of wood anatomy (ring-porous, diffuse-porous, tracheid), it has been suggested that potentially large errors in sap flow calculations may occur when using the original calibration for ring-porous species, due to large radial trends in sap velocity and/or shallow sapwood depth. Despite these concerns, sap flux measurements have rarely been calibrated in ring-porous taxa. We used a simple technique to calibrate thermal dissipation sap flux measurements on ring-porous trees in the lab. Calibration measurements were conducted on five ring-porous species in the Salt Lake City, USA metropolitan area including Quercus gambelii (Gambel oak), Gleditsia triacanthos (Honey locust), Elaeagnus angustifolia (Russian olive), Sophora japonica (Japanese pagoda), and Celtis occidentalis (Common hackberry). Six stems per species of approximately 1 m in length were instrumented with heat dissipation probes to measure sap flux concurrently with gravimetric measurements of water flow through each stem. Safranin dye was pulled through the stems following flow rate measurements to determine sapwood area. As expected, nearly all the conducting sapwood area was limited to regions within the current year growth rings. Consequently, we found that the original Granier equation underestimated sap flux density for all species considered. Our results indicate that the use of thermal dissipation probes for measuring sap flow in ring-porous species should be independently calibrated, particularly when species- specific calibration data are not available. Ring-porous taxa are widely distributed and represent an important component of the regional water budgets of many temperate regions. Our results are important for evaluating plant water

  12. Tree rings provide a new class of phenotypes for genetic associations that foster insights into adaptation of conifers to climate change.

    Science.gov (United States)

    Housset, Johann M; Nadeau, Simon; Isabel, Nathalie; Depardieu, Claire; Duchesne, Isabelle; Lenz, Patrick; Girardin, Martin P

    2018-04-01

    Local adaptation in tree species has been documented through a long history of common garden experiments where functional traits (height, bud phenology) are used as proxies for fitness. However, the ability to identify genes or genomic regions related to adaptation to climate requires the evaluation of traits that precisely reflect how and when climate exerts selective constraints. We combine dendroecology with association genetics to establish a link between genotypes, phenotypes and interannual climatic fluctuations. We illustrate this approach by examining individual tree responses embedded in the annual rings of 233 Pinus strobus trees growing in a common garden experiment representing 38 populations from the majority of its range. We found that interannual variability in growth was affected by low temperatures during spring and autumn, and by summer heat and drought. Among-population variation in climatic sensitivity was significantly correlated with the mean annual temperature of the provenance, suggesting local adaptation. Genotype-phenotype associations using these new tree-ring phenotypes validated nine candidate genes identified in a previous genetic-environment association study. Combining dendroecology with association genetics allowed us to assess tree vulnerability to past climate at fine temporal scales and provides avenues for future genomic studies on functional adaptation in forest trees. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  13. Implications of Liebig’s law of the minimum for tree-ring reconstructions of climate

    Science.gov (United States)

    Stine, A. R.; Huybers, P.

    2017-11-01

    A basic principle of ecology, known as Liebig’s Law of the Minimum, is that plant growth reflects the strongest limiting environmental factor. This principle implies that a limiting environmental factor can be inferred from historical growth and, in dendrochronology, such reconstruction is generally achieved by averaging collections of standardized tree-ring records. Averaging is optimal if growth reflects a single limiting factor and noise but not if growth also reflects locally variable stresses that intermittently limit growth. In this study a collection of Arctic tree ring records is shown to follow scaling relationships that are inconsistent with the signal-plus-noise model of tree growth but consistent with Liebig’s Law acting at the local level. Also consistent with law-of-the-minimum behavior is that reconstructions based on the least-stressed trees in a given year better-follow variations in temperature than typical approaches where all tree-ring records are averaged. Improvements in reconstruction skill occur across all frequencies, with the greatest increase at the lowest frequencies. More comprehensive statistical-ecological models of tree growth may offer further improvement in reconstruction skill.

  14. Lead isotopes in tree rings: Chronology of pollution in Bayou Trepagnier, Louisiana

    International Nuclear Information System (INIS)

    Marcantonio, F.; Flowers, G.; Thien, L.; Ellgaard, E.

    1998-01-01

    The authors have measured the Pb isotopic composition of tree rings from seven trees in both highly contaminated and relatively noncontaminated regions of Bayou Trepagnier, a bayou in southern Louisiana that has had oil refinery effluent discharged into it over the past 70 years. To their knowledge, this is the first time that Pb isotope tree-ring records have been used to assess the sources and extent of heavy-metal contamination of the environment through time. When tree ring 206 Pb/ 208 Pb and 206 Pb/ 207 Pb isotope ratios are plotted against one another, a straight line is defined by four of the most contaminated trees. This linear correlation suggests mixing between two sources of Pb. One of the sources is derived from the highly polluted dredge spoils on the banks of the bayou and the other from the natural environment. The nature of the contaminant Pb is unique in that it is, isotopically, relatively homogeneous and extremely radiogenic, similar to ores of the Mississippi Valley (i.e., 206 Pb/ 207 Pb = 1.28). This singular pollutant isotope signature has enabled them to determine the extent of Pb contamination in each cypress wood sample. The isotope results indicate that Pb uptake by the tree is dominated by local-scale root processes and is, therefore, hydrologically and chemically controlled. In addition, the authors propose that the mobility and bioavailability of Pb in the environment depends on its chemical speciation

  15. Understanding recruitment failure in tropical tree species: Insights from a tree ring study

    NARCIS (Netherlands)

    Vlam, M.; Baker, P.J.; Bunyavejchewin, S.; Mohren, G.M.J.; Zuidema, P.A.

    2014-01-01

    Many tropical tree species have population structures that exhibit strong recruitment failure. While the presence of adult trees indicates that appropriate regeneration conditions occurred in the past, it is often unclear why small individuals are absent. Knowing how, when and where these tree

  16. UV-laser microdissection system - A novel approach for the preparation of high-resolution stable isotope records (δ13C/δ18O) from tree rings

    Science.gov (United States)

    Schollaen, Karina; Helle, Gerhard

    2013-04-01

    Intra-annual stable isotope (δ13C and δ18O) studies of tree rings at various incremental resolutions have been attempting to extract valuable seasonal climatic and environmental information or assessing plant ecophysiological processes. For preparing high-resolution isotope samples normally wood segments or cores are mechanically divided in radial direction or cut in tangential direction. After mechanical dissection, wood samples are ground to a fine powder and either cellulose is extracted or bulk wood samples are analyzed. Here, we present a novel approach for the preparation of high-resolution stable isotope records from tree rings using an UV-laser microdissection system. Firstly, tree-ring cellulose is directly extracted from wholewood cross-sections largely leaving the wood anatomical structure intact and saving time as compared to the classical procedure. Secondly, micro-samples from cellulose cross-sections are dissected with an UV-Laser dissection microscope. Tissues of interest from cellulose cross-sections are identified and marked precisely with a screen-pen and dissected via an UV-laser beam. Dissected cellulose segments were automatically collected in capsules and are prepared for stable isotope (δ13C and δ18O) analysis. The new techniques facilitate inter- and intra-annual isotope analysis on tree-ring and open various possibilities for comparisons with wood anatomy in plant eco-physiological studies. We describe the design and the handling of this novel methodology and discuss advantages and constraints given by the example of intra-annual oxygen isotope analysis on tropical trees.

  17. Precipitation changes in the South American Altiplano since 1300 AD reconstructed by tree-rings

    Directory of Open Access Journals (Sweden)

    M. S. Morales

    2012-03-01

    Full Text Available Throughout the second half of the 20th century, the Central Andes has experienced significant climatic and environmental changes characterized by a persistent warming trend, an increase in elevation of the 0 °C isotherm, and sustained glacier shrinkage. These changes have occurred in conjunction with a steadily growing demand for water resources. Given the short span of instrumental hydroclimatic records in this region, longer time span records are needed to understand the nature of climate variability and to improve the predictability of precipitation, a key factor modulating the socio-economic development in the South American Altiplano and adjacent arid lowlands. In this study we present the first quasi-millennial, tree-ring based precipitation reconstruction for the South American Altiplano. This annual (November–October precipitation reconstruction is based on the Polylepis tarapacana tree-ring width series and represents the closest dendroclimatological record to the Equator in South America. This high-resolution reconstruction covers the past 707 yr and provides a unique record characterizing the occurrence of extreme events and consistent oscillations in precipitation. It also allows an assessment of the spatial and temporal stabilities of the teleconnections between rainfall in the Altiplano and hemispheric forcings such as El Niño-Southern Oscillation. Since the 1930s to present, a persistent negative trend in precipitation has been recorded in the reconstruction, with the three driest years since 1300 AD occurring in the last 70 yr. Throughout the 707 yr, the reconstruction contains a clear ENSO-like pattern at interannual to multidecadal time scales, which determines inter-hemispheric linkages between our reconstruction and other precipitation sensitive records modulated by ENSO in North America. Our reconstruction points out that century-scale dry periods are a recurrent feature in the Altiplano climate, and that the

  18. Feasibility of high-density climate reconstruction based on Forest Inventory and Analysis (FIA) collected tree-ring data

    Science.gov (United States)

    R. Justin DeRose; Shih-Yu Wang; John D. Shaw

    2013-01-01

    This study introduces a novel tree-ring dataset, with unparalleled spatial density, for use as a climate proxy. Ancillary Douglas fir and pinyon pine tree-ring data collected by the U.S. Forest Service Forest Inventory and Analysis Program (FIA data) were subjected to a series of tests to determine their feasibility as climate proxies. First, temporal coherence between...

  19. Season-specific climate signal and reconstruction from a new tree-ring network in the southwestern U.S

    Science.gov (United States)

    Griffin, D.; Woodhouse, C. A.; Meko, D. M.; Stahle, D. W.; Faulstich, H.; Leavitt, S. W.; Touchan, R.; Castro, C. L.; Carrillo, C.

    2011-12-01

    Our research group has updated existing tree-ring collections from over 50 sampling sites in the southwestern U.S. The new and archived specimens, carefully dated with dendrochronology, have been analyzed for width variations of "earlywood" and "latewood." These are the two components of annual rings in conifers that form in spring and summer, respectively. The network of primary tree-ring data has been used to develop a suite of well-replicated chronologies that extend through the 2008 growing season and are sensitive to the season-specific climate variability of the Southwest. Correlation function analysis indicates that the earlywood chronologies are closely related to cool season (October-April) precipitation variability and the chronologies derived from latewood are generally sensitive to precipitation and temperature conditions during the warm season (June-August). These proxy data originate from biological organisms and are not without bias; however, they do constitute a new means for evaluating the recent paleoclimatic history of the North American summer monsoon. The monsoon is a major component of the region's climate, impacting social and environmental systems and delivering up to 60% of the annual precipitation in the southwestern U.S. We have developed latewood-based retrodictions of monsoon precipitation that explain over half of the variance in the instrumental record, pass standard verification tests, and point to periods of persistent drought and wetness during the last 300-500 years. These reconstructions are being used to evaluate the monsoon's long-term spatiotemporal variability and its relationship to cool season climate and the major modes of ocean-atmosphere variability.

  20. Reconstructing streamflow variation of the Baker River from tree-rings in Northern Patagonia since 1765

    Science.gov (United States)

    Lara, Antonio; Bahamondez, Alejandra; González-Reyes, Alvaro; Muñoz, Ariel A.; Cuq, Emilio; Ruiz-Gómez, Carolina

    2015-10-01

    The understanding of the long-term variation of large rivers streamflow with a high economic and social relevance is necessary in order to improve the planning and management of water resources in different regions of the world. The Baker River has the highest mean discharge of those draining both slopes of the Andes South of 20°S and it is among the six rivers with the highest mean streamflow in the Pacific domain of South America (1100 m3 s-1 at its outlet). It drains an international basin of 29,000 km2 shared by Chile and Argentina and has a high ecologic and economic value including conservation, tourism, recreational fishing, and projected hydropower. This study reconstructs the austral summer - early fall (January-April) streamflow for the Baker River from Nothofagus pumilio tree-rings for the period 1765-2004. Summer streamflow represents 45.2% of the annual discharge. The regression model for the period (1961-2004) explains 54% of the variance of the Baker River streamflow (R2adj = 0.54). The most significant temporal pattern in the record is the sustained decline since the 1980s (τ = -0.633, p = 1.0144 ∗ 10-5 for the 1985-2004 period), which is unprecedented since 1765. The Correlation of the Baker streamflow with the November-April observed Southern Annular Mode (SAM) is significant (1961-2004, r = -0.55, p < 0.001). The Baker record is also correlated with the available SAM tree-ring reconstruction based on other species when both series are filtered with a 25-year spline and detrended (1765-2004, r = -0.41, p < 0.01), emphasizing SAM as the main climatic forcing of the Baker streamflow. Three of the five summers with the highest streamflow in the entire reconstructed record occurred after the 1950s (1977, 1958 and 1959). The causes of this high streamflow events are not yet clear and cannot be associated with the reported recent increase in the frequency of glacial-lake outburst floods (GLOFs). The decreasing trend in the observed and reconstructed

  1. Carbon, hydrogen oxygen isotope studies on imbedded old tree ring and paleoclimate reconstruction

    International Nuclear Information System (INIS)

    Sun Yanrong; Mu Zhiguo; Cui Haiting

    2002-01-01

    Tree ring is a kind of natural archives, on which the isotopic analysis is important to study global climate and environmental change. The authors mainly provide a comprehensive introduction to the fractionation models of carbon, hydrogen and oxygen isotope in plants, their research technique and the extract methods from cellulose. That results show isotopic tracer can record the message of climatic variation and has become a powerful tool for paleoclimate reconstruction and for the modern environment changing research. Especially studying on PAGES. the cellulose isotopic analyses of imbedded old tree ring have become the mainly quantitative means of environmental evolvement. In addition, China is a typical monsoon country, research in tree ring stable isotope seasonal variation can give a lot of important information on that. Up to now, the research techniques and works on tree ring in China are still in its earlier stage, and remain many limitations. It needs further accumulate basic research materials, intensity regional contrast and intercross studies on relative subjects

  2. Determination of self shielding factors and gamma attenuation effects for tree ring samples

    International Nuclear Information System (INIS)

    Dagistan Sahin; Kenan Uenlue

    2012-01-01

    Determination of tree ring chemistry using Neutron Activation Analysis (NAA) is part of an ongoing research between Penn State University (PSU) and Cornell University, The Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology. Tree-ring chemistry yields valuable data for environmental event signatures. These signatures are a complex function of elemental concentration. To be certain about concentration of signature elements, it is necessary to perform the measurements and corrections with the lowest error and maximum accuracy possible. Accurate and precise values of energy dependent neutron flux at dry irradiation tubes and detector efficiency for tree ring sample are calculated for Penn State Breazeale Reactor (PSBR). For the calculation of energy dependent and self shielding corrected neutron flux, detailed model of the TRIGA Mark III reactor at PSU with updated fuel compositions was prepared using the MCNP utility for reactor evolution (MURE) libraries. Dry irradiation tube, sample holder and sample were also included in the model. The thermal flux self-shielding correction factors due to the sample holder and sample for were calculated and verified with previously published values. The Geant-4 model of the gamma spectroscopy system, developed at Radiation Science and Engineering Center (RSEC), was improved and absolute detector efficiency for tree-ring samples was calculated. (author)

  3. The DCCD: a digital data infrastructure for tree-ring research

    NARCIS (Netherlands)

    Jansma, E.; Lanen, R.J. van; Brewer, P.; Kramer, R. de

    2012-01-01

    Existing on-line databases for dendrochronology are not flexible in terms of user permissions, tree-ring data formats, metadata administration and language. This is why we developed the Digital Collaboratory for Cultural Dendrochronology (DCCD). This TRiDaS-based multi-lingual database allows users

  4. Dendropedagogy: Teaching Botany, Ecology and Statistical Principles through Tree-Ring Studies.

    Science.gov (United States)

    Rubino, Darrin L.; McCarthy, Brian C.

    2002-01-01

    Develops a simple tree-ring laboratory to demonstrate the basics of dendrochronology. Provides two upper-level laboratory exercises primarily intended to demonstrate the specific dendrochronology subdisciplines of dendroclimatology and dendroecology. Suggests using the exercises separately or in unison as part of a multidisciplinary capstone…

  5. Co-occurring species differ in tree-ring δ18O trends.

    Science.gov (United States)

    John D. Marshall; Robert A. Monserud

    2006-01-01

    The stable oxygen isotope ratio (δ18O) of tree-ring cellulose is jointly determined by the δ18O of xylem water, the δ18O of atmospheric water vapor, the humidity of the atmosphere and perhaps by species-specific differences in leaf structure and function. Atmospheric...

  6. Forest response to increasing typhoon activity on the Korean peninsula: evidence from oak tree-rings

    Czech Academy of Sciences Publication Activity Database

    Altman, Jan; Doležal, Jiří; Černý, Tomáš; Song, J.-S.

    2013-01-01

    Roč. 19, č. 2 (2013), s. 498-504 ISSN 1354-1013 R&D Projects: GA ČR GAP504/12/1952; GA ČR GA206/05/0119 Institutional support: RVO:67985939 Keywords : climate change * typhoon * tree-ring analyzes Subject RIV: EH - Ecology, Behaviour Impact factor: 8.224, year: 2013

  7. Climate signal age effects in boreal tree-rings: Lessons to be learned for paleoclimatic reconstructions

    Czech Academy of Sciences Publication Activity Database

    Konter, O.; Büntgen, Ulf; Carrer, M.; Timonen, M.; Esper, J.

    2016-01-01

    Roč. 142, JUN (2016), s. 164-172 ISSN 0277-3791 Institutional support: RVO:67179843 Keywords : temperature variability * Age trends * Dendroclimatology * Growth-climate relationships * Maximum latewood density * Northern Scandinavia * Tree-ring width Subject RIV: EH - Ecology, Behaviour Impact factor: 4.797, year: 2016

  8. Relationships between salmon abundance and tree-ring δ 15N: three objective tests

    Science.gov (United States)

    D.C. Drake; Paul J. Sheppard; Robert J. Naiman

    2011-01-01

    Quantification of a relationship between salmon escapement in rivers and riparian tree-ring δ 15N could allow reconstruction of prehistorical salmon abundance. Unfortunately, attempts to quantify this link have met with little success. We examined the feasibility of the approach using natural abundance of δ 15...

  9. Measurement of 14C time scale of the rings of a tree by accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Oda, Hirotaka; Furukawa, Michiaki; Yonenobu, Hitoshi; Ikeda, Akiko; Nakamura, Toshio.

    1996-01-01

    14 C time scale is different from a histrical data in order that it is calculated by assuming that the concentration of 14 C in the sample has not been changed by age. The object of this work is to make clear the errors in measurement of 14 C time scale of the ring of a tree known the tree age. The every year ring of a Hinoki in Kiso, 950 years old, was used as a sample. The most external ring is determined as 1923 years old on the basis of the dendrochronology. The rings after 1120 years were used as the samples. α-cellulose, the most stable component in the structural components of cell of tree, was prepared from each ring. About 8 mg of α-cellulose was reduced to graphite to be measured by the tandem thoron analytic meter. The results obtained showed that 14 C time scale was older than that of the histrical data in the twelfth and thirteenth century, but it was more new than that of the histrical data from the late seventeenth to the middle of eighteenth century. The results were agreement with that of Stuiver and Pearson (1933). (S.Y.)

  10. Dendro-analysis: the study of trace elements in tree rings

    International Nuclear Information System (INIS)

    Gilboy, W.B.; Tout, R.E.; Spyrou, N.M.

    1976-01-01

    In attempts to study environmental contamination over long time scales into the past, the levels of trace and minor elements in individual tree rings have been measured using instrumental neutron activation analysis. Most measurements so far have been done on elm tree samples which are widely available due to a current epidemic of Dutch Elm disease in southern England. Samples taken from every growth ring were individually activated for ten minutes in a thermal neutron flux of 1.5 x 10 12 n cm -2 sec -1 in the 100 kW London University research reactor. The activated samples were counted for ten minutes on a 42 cm 3 Ge(Li) gamma ray detector. These procedures enabled the following radioisotopes to be monitored for a large number of samples: 19 0, 24 Na, 27 Mg, 28 Al, 38 Cl, 42 K, 49 Ca, 56 Mn, 66 Cu, 80 Br, 87 /sup m/Sr, 41 Ar, 128 I, 139 Ba. Some of the above isotopes show striking systematic variations both from ring to ring in a radial direction, and also around individual rings. Results are described in detail for samples taken from trees grown in various locations and assesses the potential of this technique for studying past environmental conditions

  11. Eco-monitoring of highly contaminated areas: historic heavy metal contamination in tree ring records

    Science.gov (United States)

    Baross, Norbert; Jordán, Győző; Albert, Julianna; Abdaal, Ahmed; Anton, Attila

    2014-05-01

    This study examines and compares tree rings of trees grown in a mining area highly contaminated with heavy metals. Tree rings offers an excellent opportunity for eco-monitoring polluted areas. Contamination dispersion from the source to the receptors can be studied in time and space. The sampled area is located in the eastern part of the Matra Mts. of the Inner-Carpathian calc-alkaline Volcanic Arc (Hungary) with abundant historical ore (Pb, Zn, Cu, etc.) mining in the area. Dense forests are composed of the most typical association of the Turkey oak (Quercus cerris). Scots pine (Pinus sylvestris), European black pine (Pinus nigra), oak (Quercus robur), beech (Fagus sylvatica), and hornbeam (Carpinus betulus) also occurs in the landscape. Sampled trees are located within a 1km radius of the abandoned historic ore mines. Sample sites were located above the old mines and waste rock heaps, under the waste rock heaps and on the floodplain of the Ilona Creek. The sampled trees were selected by the following criteria: the tree should be healthy, showing no signs of thunderbolt or diseases and having a minimum diameter of 50 cm. Samples were taken with a tree borer at the height of 150 cm. At the same time, soil samples were also taken near the trees in a 25 cm depth. Prior to laboratory analysis, the samples measured and air dried. Every fifth years tree ring was taken from the samples under microscope, working backwards from the most recent outer ring (2012, the year of the sampling). Samples were digested with a mixture of H2SO4 and H2O2m in Teflon vessels in a microwave unit. The samples were analyzed by ICP-OES instrument. The results were evaluated with statistical method. Results revealed a consistent picture showing distinct locations and years of the contamination history in the former mining area. Some elements are built into the trees more efficiently than other elements depending on mobility in the soil solution that is influenced by soil chemical properties

  12. Multielemental analyses of tree rings by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Hall, G.S.

    1990-01-01

    Inductively coupled plasma mass spectrometry (ICP-MS) was evaluated for major, minor, trace, and ultra-trace elemental analyses of individual tree rings. The samples were obtained from an old-growth Douglas fir growing near Mount St. Helens volcano, and from trees at various other North American sites. Eightly percent of elements from Li to U had detection limits in the solid (wood) below 8.0 ng g -1 . Two anomalous peaks occur in Mount St. Helens samples at A.D. 1478 and 1490 that closely correlate with past eruptions of the volcano. These results show that ICP-MS is a rapid and sensitive analytical method for multielemental analyses of individual tree rings. (author) 16 refs.; 2 figs.; 2 tabs

  13. Seasonal transfer of oxygen isotopes from precipitation and soil to the tree ring: source water versus needle water enrichment.

    Science.gov (United States)

    Treydte, Kerstin; Boda, Sonja; Graf Pannatier, Elisabeth; Fonti, Patrick; Frank, David; Ullrich, Bastian; Saurer, Matthias; Siegwolf, Rolf; Battipaglia, Giovanna; Werner, Willy; Gessler, Arthur

    2014-05-01

    For accurate interpretation of oxygen isotopes in tree rings (δ(18) O), it is necessary to disentangle the mechanisms underlying the variations in the tree's internal water cycle and to understand the transfer of source versus leaf water δ(18) O to phloem sugars and stem wood. We studied the seasonal transfer of oxygen isotopes from precipitation and soil water through the xylem, needles and phloem to the tree rings of Larix decidua at two alpine sites in the Lötschental (Switzerland). Weekly resolved δ(18) O records of precipitation, soil water, xylem and needle water, phloem organic matter and tree rings were developed. Week-to-week variations in needle-water (18) O enrichment were strongly controlled by weather conditions during the growing season. These short-term variations were, however, not significantly fingerprinted in tree-ring δ(18) O. Instead, seasonal trends in tree-ring δ(18) O predominantly mirrored trends in the source water, including recent precipitation and soil water pools. Modelling results support these findings: seasonal tree-ring δ(18) O variations are captured best when the week-to-week variations of the leaf water signal are suppressed. Our results suggest that climate signals in tree-ring δ(18) O variations should be strongest at temperate sites with humid conditions and precipitation maxima during the growing season. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  14. The effect of contaminated groundwater on tree growth: A tree-ring analysis

    International Nuclear Information System (INIS)

    LeBlanc, D.C.; Loehle, C.

    1990-10-01

    A study was conducted on the effect of contaminated groundwater seepage on tree growth downslope from F- and H-Area seepage basins of the Savannah River Site. Trees in wetlands along Four Mile Creek began to show localized stress and mortality in the late 1970s. Extreme winter temperatures and high rainfall were ruled out as potential causal factors of tree stress. Drought was shown to affect trees in both contaminated and uncontaminated zones, but trees in uncontaminated areas exhibit better recovery after drought than trees in contaminated areas. Pollution-mediated alteration of soil acidity and aluminum, sodium, and heavy metal concentrations likely acted to predispose trees to decline, with severe drought acting as the trigger for decline initiation and tree death. Thus, a moderate pollution loading, not sufficient to cause visible damage of itself, may create conditions in which sudden, severe decline could result from natural stresses. This mechanism of forest decline is common, and should be considered in evaluations of the impact of pollution on wetland forest systems. 28 refs., 4 figs., 6 tabs

  15. Biophysical modelling of intra-ring variations in tracheid features and wood density of Pinus pinaster trees exposed to seasonal droughts.

    Science.gov (United States)

    Wilkinson, Sarah; Ogée, Jérôme; Domec, Jean-Christophe; Rayment, Mark; Wingate, Lisa

    2015-03-01

    Process-based models that link seasonally varying environmental signals to morphological features within tree rings are essential tools to predict tree growth response and commercially important wood quality traits under future climate scenarios. This study evaluated model portrayal of radial growth and wood anatomy observations within a mature maritime pine (Pinus pinaster (L.) Aït.) stand exposed to seasonal droughts. Intra-annual variations in tracheid anatomy and wood density were identified through image analysis and X-ray densitometry on stem cores covering the growth period 1999-2010. A cambial growth model was integrated with modelled plant water status and sugar availability from the soil-plant-atmosphere transfer model MuSICA to generate estimates of cell number, cell volume, cell mass and wood density on a weekly time step. The model successfully predicted inter-annual variations in cell number, ring width and maximum wood density. The model was also able to predict the occurrence of special anatomical features such as intra-annual density fluctuations (IADFs) in growth rings. Since cell wall thickness remained surprisingly constant within and between growth rings, variations in wood density were primarily the result of variations in lumen diameter, both in the model and anatomical data. In the model, changes in plant water status were identified as the main driver of the IADFs through a direct effect on cell volume. The anatomy data also revealed that a trade-off existed between hydraulic safety and hydraulic efficiency. Although a simplified description of cambial physiology is presented, this integrated modelling approach shows potential value for identifying universal patterns of tree-ring growth and anatomical features over a broad climatic gradient. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Synoptic-scale circulation patterns during summer derived from tree rings in mid-latitude Asia

    Science.gov (United States)

    Seim, Andrea; Schultz, Johannes A.; Leland, Caroline; Davi, Nicole; Byambasuren, Oyunsanaa; Liang, Eryuan; Wang, Xiaochun; Beck, Christoph; Linderholm, Hans W.; Pederson, Neil

    2017-09-01

    Understanding past and recent climate and atmospheric circulation variability is vital for regions that are affected by climate extremes. In mid-latitude Asia, however, the synoptic climatology is complex and not yet fully understood. The aim of this study was to investigate dominant synoptic-scale circulation patterns during the summer season using a multi-species tree-ring width (TRW) network comprising 78 sites from mid-latitude Asia. For each TRW chronology, we calculated an atmospheric circulation tree-ring index (ACTI), based on 1000 hPa geopotential height data, to directly link tree growth to 13 summertime weather types and their associated local climate conditions for the period 1871-1993. Using the ACTI, three groups of similarly responding tree-ring sites can be associated with distinct large-scale atmospheric circulation patterns: 1. growth of drought sensitive trees is positively affected by a cyclone over northern Russia; 2. temperature sensitive trees show positive associations to a cyclone over northwestern Russia and an anticyclone over Mongolia; 3. trees at two high elevation sites show positive relations to a zonal cyclone extending from mid-latitude Eurasia to the West Pacific. The identified synoptic-scale circulation patterns showed spatiotemporal variability in their intensity and position, causing temporally varying climate conditions in mid-latitude Asia. Our results highlight that for regions with less pronounced atmospheric action centers during summer such as the occurrence of large-scale cyclones and anticyclones, synoptic-scale circulation patterns can be extracted and linked to the Northern Hemisphere circulation system. Thus, we provide a new and solid envelope for climate studies covering the past to the future.

  17. Process based model sheds light on climate sensitivity of Mediterranean tree-ring width

    Directory of Open Access Journals (Sweden)

    R. Touchan

    2012-03-01

    Full Text Available We use the process-based VS (Vaganov-Shashkin model to investigate whether a regional Pinus halepensis tree-ring chronology from Tunisia can be simulated as a function of climate alone by employing a biological model linking day length and daily temperature and precipitation (AD 1959–2004 from a climate station to ring-width variations. We check performance of the model on independent data by a validation exercise in which the model's parameters are tuned using data for 1982–2004 and the model is applied to generate tree-ring indices for 1959–1981. The validation exercise yields a highly significant positive correlation between the residual chronology and estimated growth curve (r=0.76 p<0.0001, n=23. The model shows that the average duration of the growing season is 191 days, with considerable variation from year to year. On average, soil moisture limits tree-ring growth for 128 days and temperature for 63 days. Model results depend on chosen values of parameters, in particular a parameter specifying a balance ratio between soil moisture and precipitation. Future work in the Mediterranean region should include multi-year natural experiments to verify patterns of cambial-growth variation suggested by the VS model.

  18. Intramolecular 13C analysis of tree rings provides multiple plant ecophysiology signals covering decades.

    Science.gov (United States)

    Wieloch, Thomas; Ehlers, Ina; Yu, Jun; Frank, David; Grabner, Michael; Gessler, Arthur; Schleucher, Jürgen

    2018-03-22

    Measurements of carbon isotope contents of plant organic matter provide important information in diverse fields such as plant breeding, ecophysiology, biogeochemistry and paleoclimatology. They are currently based on 13 C/ 12 C ratios of specific, whole metabolites, but we show here that intramolecular ratios provide higher resolution information. In the glucose units of tree-ring cellulose of 12 tree species, we detected large differences in 13 C/ 12 C ratios (>10‰) among carbon atoms, which provide isotopically distinct inputs to major global C pools, including wood and soil organic matter. Thus, considering position-specific differences can improve characterisation of soil-to-atmosphere carbon fluxes and soil metabolism. In a Pinus nigra tree-ring archive formed from 1961 to 1995, we found novel 13 C signals, and show that intramolecular analysis enables more comprehensive and precise signal extraction from tree rings, and thus higher resolution reconstruction of plants' responses to climate change. Moreover, we propose an ecophysiological mechanism for the introduction of a 13 C signal, which links an environmental shift to the triggered metabolic shift and its intramolecular 13 C signature. In conclusion, intramolecular 13 C analyses can provide valuable new information about long-term metabolic dynamics for numerous applications.

  19. Long-term effects of drought on tree-ring growth and carbon isotope variability in Scots pine in a dry environment.

    Science.gov (United States)

    Timofeeva, Galina; Treydte, Kerstin; Bugmann, Harald; Rigling, Andreas; Schaub, Marcus; Siegwolf, Rolf; Saurer, Matthias

    2017-08-01

    Drought frequency is increasing in many parts of the world and may enhance tree decline and mortality. The underlying physiological mechanisms are poorly understood, however, particularly regarding chronic effects of long-term drought and the response to increasing temperature and vapor pressure deficit (VPD). We combined analyses of radial growth and stable carbon isotope ratios (δ13C) in tree rings in a mature Scots pine (Pinus sylvestris L.) forest over the 20th century to elucidate causes of tree mortality in one of the driest parts of the European Alps (Pfynwald, Switzerland). We further compared trees that have recently died with living trees in a 10-year irrigation experiment, where annual precipitation was doubled. We found a sustained growth increase and immediate depletion of δ13C values for irrigated trees, indicating higher stomatal conductance and thus indeed demonstrating that water is a key limiting factor for growth. Growth of the now-dead trees started declining in the mid-1980s, when both mean temperature and VPD increased strongly. But growth of these trees was reduced to some extent already several decades earlier, while intrinsic water-use efficiency derived from δ13C values was higher. This indicates a more conservative water-use strategy compared with surviving trees, possibly at the cost of low carbon uptake and long-term reduction of the needle mass. We observed reduced climatic sensitivity of raw tree-ring δ13C for the now-dead in contrast to surviving trees, indicating impaired stomatal regulation, although this difference between the tree groups was smaller after detrending the data. Higher autocorrelation and a lower inter-annual δ13C variability of the now-dead trees further indicates a strong dependence on (low) carbon reserves. We conclude that the recent increase in atmospheric moisture demand in combination with insufficient soil water supply was the main trigger for mortality of those trees that were weakened by long

  20. Missing rings in Pinus halepensis – the missing link to relate the tree-ring record to extreme climatic events

    Science.gov (United States)

    Klemen Novak; Martin de Luis; Miguel A. Saz; Luis A. Longares; Roberto Serrano-Notivoli; Josep Raventos; Katarina Cufar; Jozica Gricar; Alfredo Di Filippo; Gianluca Piovesan; Cyrille B.K. Rathgeber; Andreas Papadopoulos; Kevin T. Smith

    2016-01-01

    Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of...

  1. Detecting long-term growth trends using tree rings: a critical evaluation of methods.

    Science.gov (United States)

    Peters, Richard L; Groenendijk, Peter; Vlam, Mart; Zuidema, Pieter A

    2015-05-01

    Tree-ring analysis is often used to assess long-term trends in tree growth. A variety of growth-trend detection methods (GDMs) exist to disentangle age/size trends in growth from long-term growth changes. However, these detrending methods strongly differ in approach, with possible implications for their output. Here, we critically evaluate the consistency, sensitivity, reliability and accuracy of four most widely used GDMs: conservative detrending (CD) applies mathematical functions to correct for decreasing ring widths with age; basal area correction (BAC) transforms diameter into basal area growth; regional curve standardization (RCS) detrends individual tree-ring series using average age/size trends; and size class isolation (SCI) calculates growth trends within separate size classes. First, we evaluated whether these GDMs produce consistent results applied to an empirical tree-ring data set of Melia azedarach, a tropical tree species from Thailand. Three GDMs yielded similar results - a growth decline over time - but the widely used CD method did not detect any change. Second, we assessed the sensitivity (probability of correct growth-trend detection), reliability (100% minus probability of detecting false trends) and accuracy (whether the strength of imposed trends is correctly detected) of these GDMs, by applying them to simulated growth trajectories with different imposed trends: no trend, strong trends (-6% and +6% change per decade) and weak trends (-2%, +2%). All methods except CD, showed high sensitivity, reliability and accuracy to detect strong imposed trends. However, these were considerably lower in the weak or no-trend scenarios. BAC showed good sensitivity and accuracy, but low reliability, indicating uncertainty of trend detection using this method. Our study reveals that the choice of GDM influences results of growth-trend studies. We recommend applying multiple methods when analysing trends and encourage performing sensitivity and reliability

  2. Tree ring variability and climate response of Abies spectabilis along an elevation gradient in Mustang, Nepal

    DEFF Research Database (Denmark)

    Kharal, D.K.; Meilby, Henrik; Rayamajhi, S.

    2014-01-01

    In mountainous areas including the Himalayas, tree lines are expected to advance to higher altitudes due to global climate change affecting the distribution and growth of plant species. This study aimed at identifying the tree ring variability of Abies spectabilis (D. Don) and its response...... to the climate along an elevation gradient in the high Himalayas of central Nepal. Tree core samples were collected from four sites in Mustang district. All sites were located in the same valley and exposed to similar weather conditions. Out of 232 samples collected from the sites, Titi lower (2700 m), Titi......-elevation sites the correlation between pre-monsoon precipitation and tree growth was positive, and for the month of May this was statistically significant (ptree growth at all sites, and at the upper elevation...

  3. Tree ring evidence of a 20th century precipitation surge in the monsoon shadow zone of the western Himalaya, India

    Science.gov (United States)

    Yadav, Ram R.

    2011-01-01

    The present study is the first attempt to develop an annual (August-July) precipitation series back to AD 1330 using a tree ring data network of Himalayan cedar (Cedrus deodara (Roxb.) G. Don) from the Lahaul-Spiti region in the western Himalaya, India. The rainfall reconstruction reveals high magnitude multidecadal droughts during the 14th and 15th centuries and thenceforth a gradual increase in precipitation. Increasingly wet conditions during the 20th century are consistent with other long-term precipitation reconstructions from high Asia and reflect a large-scale intensification of the hydrological cycle, coincident with what is anticipated due to global warming. Significant relationships between reconstructed precipitation and precipitation records from central southwest Asia, east of the Caspian Sea, ENSO (NINO4-SST) variability and summer monsoon rainfall over central northeast India underscore the utility of our data in synoptic climatology.

  4. 400 years of summer climatic conditions in the N Carpathian Mts. (eastern Europe) based on O and C stable isotopes in Pinus Cembra L tree rings

    Science.gov (United States)

    Nagavciuc, Viorica; Popa, Ionel; Kern, Zoltán; Persoiu, Aurel

    2016-04-01

    For a better understanding of how the climate is changing and how the environment responds to these changes, it is necessary to understand how the climate has varied in the past. Romania's virgin forests have a great potential to obtain long tree-ring chronologies with annual resolution; but so far, only a few studies resulted in quantitative paleoclimatic reconstructions. In this context, the aim of this study is 1) to calibrate the relationship between the stable isotopes of oxygen and carbon in tree rings and the main climatic parameters and determine the potential of Pinus cembra (Cǎlimani Mts., N Romania, Eastern Europe) for paleoclimatic reconstructions; 2) to provide the first palaeoclimatic reconstitution in Romania based on the isotopic composition of oxygen and carbon in tree ring cellulose, and 3) to test the hypothesis that nearby sulphur mines have not altered the climatic signal recorded by the stable isotopic composition of tree rings, contrary to the similar signal recorded by TRW. For this study, we have analysed wood samples of Swiss stone pine (Pinus cembra L.) from living and dead trees from Cǎlimani Mts., NE Romania, aged between 1600 and 2012 AD. The isotopic composition of oxygen and carbon from the cellulose was analysed at the Institute for Geological and Geochemical Research, Budapest, Hungary, using a high-temperature pyrolysis system (Thermo Quest TC-EA) coupled to an isotope ratio mass spectrometer (Thermo Finningan Delta V) following a ring by ring (i.e., non-pooled) approach. The average level of δ18O and δ13C in cellulose for the period 1600-2012 was 28.83‰ and -22.63 ‰. The tree ring cellulose δ18O and δ13C values showed a strong positive correlation with maximum air temperature (r = 0.6 for δ18O and r = 0.5 for δ13C), mean temperature (r = 0.6 for δ18O and r = 0.45 for δ13C), and sunshine duration (r = 0.69 for δ18O) and negatively correlated with precipitation amount (r = -0.5 for δ18O and r = 0.3 for δ13C) and

  5. Preliminary study on the relationship between trends of tree-ring δ 13C series and site conditions

    International Nuclear Information System (INIS)

    Chen Tuo; Qin Dahe; Liu Xiaohong; Ren Jiawen

    2001-01-01

    The long-term trends of tree-ring δ 13 C series, taken respectively from Qilian of Qinghai and Zhaosu and Aleitai of xinjiang were compared. The results showed that a similar trend existed between Qilian series and Zhaosu series, while there was a significant difference between them and Aleitai series. The authors' analysis indicated that the site difference of the trends of tree-ring δ 13 C series was mainly associated with 'canopy effects' of tree growth. It is suggested that tree samples should be selected from sparse forests or the sampled tree foliage high above the whole canopy when the history of δ 13 C of atmospheric CO 2 was reconstructed by tree-ring series

  6. New paleoclimatic database for the Iberian Peninsula since AD 1700 inferred from tree-ring records and documentary evidence: advances in temperature and drought variability reconstructions

    Science.gov (United States)

    Tejedor, Ernesto; Ángel Saz, Miguel; de Luis, Martín; Esper, Jan; Barriendos, Mariano; Serrano-Notivoli, Roberto; Novak, Klemen; Longares, Luis Alberto; Martínez-del Castillo, Edurne; María Cuadrat, José

    2017-04-01

    A substantial increase of surface air temperatures in the upcoming decades, particularly significant in the Mediterranean basin, has been reported by the IPCC (IPCC, 2013). It is therefore particularly important to study past climate extremes and variability in this region, which will in turn support the accuracy of future climate scenarios. Yet, our knowledge of past climate variability and trends is limited by the shortage of instrumental data prior to the twentieth century, which prompts to the need of discovering new sources with which to reconstruct past climate. We here present a new paleoclimatic database for the northeast of the Iberian Peninsula based on tree-ring records, documentary evidence and instrumental data. The network includes 774 tree-ring, earlywood and latewood width series from Pinus uncinata, Pinus sylvestris and Pinus nigra trees in the Pyrenees and Iberian Range reaching back to AD 1510. Three reconstructions are developed using these samples; an annual drought reconstruction since AD 1694, a summer drought reconstruction since AD 1734, and a maximum temperature reconstruction since AD 1604. Additionally, the documentary records from 16 locations in the Ebro Valley are examined focusing on climate-related 'rogations'. We differentiated three types of rogations, considering the importance of religious acts, to identify the severity of drought and pluvial events. Finally, an attempt to explore the links between documentary and tree-ring based reconstructions is presented.

  7. Spatial and temporal variation of radiocarbon in tree rings - some preliminary results

    International Nuclear Information System (INIS)

    Higham, T.F.G.; Hogg, A.G.; McCormac, F.G.; Baillie, M.G.L.; Brown, D.; Palmer, J.G.; Xiong, L.

    1997-01-01

    A number of researchers have identified a measurable difference between the 14 C activities of tree rings of identical dendochronological age between the Northern and the Southern Hemispheres. It is also acknowledged that there is an urgent need for new high precision Δ 14 C data from tree rings in both Hemispheres to help resolve the questions relating to the magnitude and cause of the locality and temporal dependence of the Δ 14 C record, to provide a reliable Southern Hemisphere calibration curve and to throw light upon the 1986 and 1993 Calibration data set discrepancies. In this paper, the authors present the research design of a project to investigate these critical issues in radiocarbon age calibration and describe the preliminary results

  8. Spatial and temporal variation of radiocarbon in tree rings - some preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Higham, T.F.G.; Hogg, A.G. [Waikato Univ., Hamilton (New Zealand); McCormac, F.G.; Baillie, M.G.L.; Brown, D. [Queens`s University, Belfast, (Ireland). School of Geosciences; Palmer, J.G.; Xiong, L. [Lincoln University, Canterbury (New Zealand). Department of Plant Science

    1997-12-31

    A number of researchers have identified a measurable difference between the {sup 14}C activities of tree rings of identical dendochronological age between the Northern and the Southern Hemispheres. It is also acknowledged that there is an urgent need for new high precision {Delta}{sup 14}C data from tree rings in both Hemispheres to help resolve the questions relating to the magnitude and cause of the locality and temporal dependence of the {Delta}{sup 14}C record, to provide a reliable Southern Hemisphere calibration curve and to throw light upon the 1986 and 1993 Calibration data set discrepancies. In this paper, the authors present the research design of a project to investigate these critical issues in radiocarbon age calibration and describe the preliminary results. Paper no. 30; Extended abstract; 12 refs.

  9. Annual ring validation of the south african sardine Sardinops sagax ...

    African Journals Online (AJOL)

    A total of 21 sardine Sardinops sagax otoliths, collected in winter and spring 1994, were examined with a scanning electron microscope to validate growth zones using daily growth increments. Increment numbers and widths for the first, second and third annual growth zones served to back-calculate hatching dates and to ...

  10. No evidence for consistent long-term growth stimulation of 13 tropical tree species: results from tree-ring analysis.

    Science.gov (United States)

    Groenendijk, Peter; van der Sleen, Peter; Vlam, Mart; Bunyavejchewin, Sarayudh; Bongers, Frans; Zuidema, Pieter A

    2015-10-01

    The important role of tropical forests in the global carbon cycle makes it imperative to assess changes in their carbon dynamics for accurate projections of future climate-vegetation feedbacks. Forest monitoring studies conducted over the past decades have found evidence for both increasing and decreasing growth rates of tropical forest trees. The limited duration of these studies restrained analyses to decadal scales, and it is still unclear whether growth changes occurred over longer time scales, as would be expected if CO2 -fertilization stimulated tree growth. Furthermore, studies have so far dealt with changes in biomass gain at forest-stand level, but insights into species-specific growth changes - that ultimately determine community-level responses - are lacking. Here, we analyse species-specific growth changes on a centennial scale, using growth data from tree-ring analysis for 13 tree species (~1300 trees), from three sites distributed across the tropics. We used an established (regional curve standardization) and a new (size-class isolation) growth-trend detection method and explicitly assessed the influence of biases on the trend detection. In addition, we assessed whether aggregated trends were present within and across study sites. We found evidence for decreasing growth rates over time for 8-10 species, whereas increases were noted for two species and one showed no trend. Additionally, we found evidence for weak aggregated growth decreases at the site in Thailand and when analysing all sites simultaneously. The observed growth reductions suggest deteriorating growth conditions, perhaps due to warming. However, other causes cannot be excluded, such as recovery from large-scale disturbances or changing forest dynamics. Our findings contrast growth patterns that would be expected if elevated CO2 would stimulate tree growth. These results suggest that commonly assumed growth increases of tropical forests may not occur, which could lead to erroneous

  11. A stable lead isotopic investigation of the use of sycamore tree rings as a historical biomonitor of environmental lead contamination

    Energy Technology Data Exchange (ETDEWEB)

    Patrick, Gavin J. [School of GeoSciences, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JJ, Scotland (United Kingdom); Farmer, John G. [School of GeoSciences, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JJ, Scotland (United Kingdom)]. E-mail: J.G.Farmer@ed.ac.uk

    2006-06-01

    from the mine, features not observed in any other trees along the transect. Overall the data suggest that sycamore tree-ring analysis is an unsuitable method for obtaining records of historical lead deposition in areas with no large local lead input, although it can reveal some information about the temporal and spatial influence of point source emitters. The unsuitability probably arises from the number of active annual rings in a single year, the post-uptake radial translocation of elements, the relative importance of the different routes of uptake, and the soil depth(s) from which trees draw nutrients.

  12. The mobility of nitrogen across tree-rings of Norway spruce (Picea abies L.) and the effect of extraction method on tree-ring δ¹⁵N and δ¹³C values.

    Science.gov (United States)

    Tomlinson, G; Siegwolf, R T W; Buchmann, N; Schleppi, P; Waldner, P; Weber, P

    2014-06-15

    The use of stable nitrogen (N) isotope ratios (δ(15)N values) in dendroecological studies is often preceded by an extraction procedure using organic solvents to remove mobile N compounds from tree-rings. Although these mobile N compounds may be capable of distorting potential environmental signals in the tree-ring δ(15)N values, recent investigations question the necessity of such an extraction. We used an on-going experiment with simulated elevated N deposition previously labelled with (15)N, in conjunction with control trees, to investigate the necessity of extracting mobile N compounds (using a rapid extraction procedure) for tree-ring δ(15)N and δ(13)C studies, as well as N and C concentration analyses. In addition, we examined the magnitude of radial redistribution of N across tree-rings of Norway spruce (Picea abies). The (15)N label, applied in 1995/96, was found in tree-rings as far back as 1951, although the increased N availability did not cause any significant relative increase in tree growth. The rapid extraction procedure had no significant effect on tree-ring δ(15)N or δ(13)C values in either labelled or control trees, or on N concentration. The C concentrations, however, were significantly higher after extraction in control samples, with the opposite effect observed in labelled samples. Our results indicate that the extraction of mobile N compounds through the rapid extraction procedure is not necessary prior to the determination of Norway spruce δ(15)N or δ(13)C values in dendrochemical studies. δ(15)N values, however, must be interpreted with great care, particularly when used as a proxy for the N status of trees, due to the very high mobility of N within the tree stem sapwood of Norway spruce over several decades. Copyright © 2014 John Wiley & Sons, Ltd.

  13. Last millennium northern hemisphere summer temperatures from tree rings: Part I: The long term context

    Czech Academy of Sciences Publication Activity Database

    Wilson, R.; Anchukaitis, K.; Briffa, K. R.; Büntgen, Ulf; Cook, E.; D'Arrigo, R.; Davi, N.; Esper, J.; Frank, D.; Gunnarson, B.; Hegerl, G.; Helama, S.; Klesse, S.; Krusic, P. J.; Linderholm, H. W.; Myglan, V. S.; Osborn, T. J.; Rydval, M.; Schneider, L.; Schurer, A.; Wiles, G.; Zhang, P.; Zorita, E.

    2016-01-01

    Roč. 134, FEB (2016), s. 1-18 ISSN 0277-3791 Institutional support: RVO:67179843 Keywords : high-resolution paleoclimatology * stable carbon isotopes * medieval warm period * past 600 years * blue intensity * volcanic-eruptions * density data * ice-age * dendroclimatic reconstruction * cambium phenology * Tree-rings * Northern hemisphere * Last millennium * Summer temperatures * Reconstruction * CMIP5 models Subject RIV: EH - Ecology, Behaviour Impact factor: 4.797, year: 2016

  14. Detecting influences on California drought intervals using isotopes in tree-ring cellulose

    Science.gov (United States)

    Kanner, L. C.; Buenning, N. H.; Stott, L. D.; Stahle, D. W.

    2012-12-01

    Multi-decadal drought events have characterized climate variability in California over the last century. However, the causes of interannual precipitation variability and the origins of multi-decadal drought in California remain unclear. We utilize the oxygen isotopic composition (δ18O) of tree-ring cellulose in combination with previously developed ring-width measurements to trace the delivery of moisture to the region and investigate ocean-atmosphere patterns that might generate prolonged drought. Of the 36 Quercus douglasii (blue oak) sites in the California central valley, we have focused our work at two locations - one north of Los Angeles (34.74°N, 120°W, 1036 masl) and the other east of San Francisco (37.88°N 121.97°W, 182 masl). Using cores from at least five different trees at each location, tree-ring cellulose δ18O was measured for each year of growth from 1954 to 2004. The δ18O values of tree-ring cellulose range from 29‰ to 34‰ (VSMOW) at both sites and exhibit shared interannual variance (r = 0.43, p shifts in the moisture source region are of primary importance because moisture from high latitude sources has a lower isotopic composition compared to subtropical regions. Using NCAR reanalysis data, wind field anomalies suggest that moisture is derived from the north during dry years (low δ18O) and from the subtropics during wet years (high δ18O). Additional processes such as condensation height and post-condensation effects may also be important in controlling isotopic variability.

  15. A Wireless Fatigue Monitoring System Utilizing a Bio-Inspired Tree Ring Data Tracking Technique

    OpenAIRE

    Bai, Shi; Li, Xuan; Xie, Zhaohui; Zhou, Zhi; Ou, Jinping

    2014-01-01

    Fatigue, a hot scientific research topic for centuries, can trigger sudden failure of critical structures such as aircraft and railway systems, resulting in enormous casualties as well as economic losses. The fatigue life of certain structures is intrinsically random and few monitoring techniques are capable of tracking the full life-cycle fatigue damage. In this paper, a novel in-situ wireless real-time fatigue monitoring system using a bio-inspired tree ring data tracking technique is propo...

  16. Traffic pollution affects tree-ring width and isotopic composition of Pinus pinea

    International Nuclear Information System (INIS)

    Battipaglia, Giovanna; Marzaioli, Fabio; Lubritto, Carmine; Altieri, Simona; Strumia, Sandro; Cherubini, Paolo; Cotrufo, M. Francesca

    2010-01-01

    This study presents new evidence that radiocarbon, combined with dendrochronological and stable isotopes analysis in tree rings and needles, can help to better understand the influence of pollution on trees. Pinus pinea individuals, adjacent to main roads in the urban area of Caserta (South Italy) and exposed to large amounts of traffic exhaust since 1980, were sampled and the time-related trend in the growth residuals was estimated. We found a consistent decrease in the ring width starting from 1980, with a slight increase in δ 13 C value, which was considered to be a consequence of environmental stress. No clear pattern was identified in δ 15 N, while an increasing effect of the fossil fuel dilution on the atmospheric bomb-enriched 14 C background was detected in tree rings, possibly as a consequence of the increase in traffic exhausts. Our findings suggested that radiocarbon is a very sensitive tool to investigate small-scale (i.e. traffic exhaust at the level crossing) and large-scale (urban area pollution) induced disturbances.

  17. Winter-spring precipitation reconstructions from tree rings for northeast Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva-Diaz, J.; Cerano-Paredes, J. [Instituto Nacional de Investigaciones Forestales y Agropecuarias, Centro Nacional de Investigacion Disciplinarioa en Relacion Agua, Suelo, Planta. Km 6.5 Margen Derecha del Canal Sacramento Gomez Palacio, Durango, 35140 (Mexico); Stahle, D.W.; Cleaveland, M.K. [Tree-Ring Laboratory, Department of Geosciences, University of Arkansas, fayetteville, Arkansas 72701 (United States); Luckman, B.H. [Department of Geography, University of Western Ontario, London, Ontario, N6A5C3 (Canada); Therrell, M.D. [Department of Environmental Sciences, University of Virginia, Charlottesville, VA 29904 (United States); Cornejo-Oviedo, E. [Departamento Forestal, Universidad Autonoma Agraria Antonio Narro, Saltillo, Coahuila (Mexico)

    2007-07-15

    The understanding of historic hydroclimatic variability is basic for planning proper management of limited water resources in northeastern Mexico. The objective of this study was to develop a network of tree-ring chronologies to reconstruct hydroclimate variability in northeastern Mexico and to analyze the influence of large-scale circulation patterns, such as ENSO. Precipitation sensitive tree-ring chronologies of Douglas-fir were developed in mountain ranges of the Sierra Madre Oriental and used to produce winter-spring precipitation reconstructions for central and southern Nuevo Leon, and southeastern Coahuila. The seasonal winter-spring precipitation reconstructions are 342 years long (1659-2001) for Saltillo, Coahuila and 602 years long (1400-2002) for central and southern Nuevo Leon. Both reconstructions show droughts in the 1810s, 1870s, 1890s, 1910s, and 1970s, and wet periods in the 1770s, 1930s, 1960s, and 1980s. Prior to 1800s the reconstructions are less similar. The impact of ENSO in northeastern Mexico (as measured by the Tropical Rainfall Index) indicated long-term instability of the Pacific equatorial teleconnection. Atmospheric circulation systems coming from higher latitudes (cold fronts or 'nortes') and others developed in the Gulf of Mexico (tropical storms, hurricanes) also influence the climatic conditions characterizing this region. The recent development of new and longer tree-ring chronologies for the region will contribute to a better understanding of the interannual and multidecadal climatic variability of northeastern Mexico.

  18. Traffic pollution affects tree-ring width and isotopic composition of Pinus pinea

    Energy Technology Data Exchange (ETDEWEB)

    Battipaglia, Giovanna, E-mail: giovanna.battipaglia@wsl.ch [WSL Swiss Federal Institute for Forest, Snow and Landscape Research, CH-8903 Birmensdorf (Switzerland); Department of Environmental Sciences, Second University of Naples, Via Vivaldi 43, I-81100 Caserta (Italy); Marzaioli, Fabio; Lubritto, Carmine; Altieri, Simona; Strumia, Sandro [Department of Environmental Sciences, Second University of Naples, Via Vivaldi 43, I-81100 Caserta (Italy); Cherubini, Paolo [WSL Swiss Federal Institute for Forest, Snow and Landscape Research, CH-8903 Birmensdorf (Switzerland); Cotrufo, M. Francesca [Department of Environmental Sciences, Second University of Naples, Via Vivaldi 43, I-81100 Caserta (Italy); Department of Soil and Crop Sciences, Colorado State University, CO (United States)

    2010-01-01

    This study presents new evidence that radiocarbon, combined with dendrochronological and stable isotopes analysis in tree rings and needles, can help to better understand the influence of pollution on trees. Pinus pinea individuals, adjacent to main roads in the urban area of Caserta (South Italy) and exposed to large amounts of traffic exhaust since 1980, were sampled and the time-related trend in the growth residuals was estimated. We found a consistent decrease in the ring width starting from 1980, with a slight increase in {delta}{sup 13}C value, which was considered to be a consequence of environmental stress. No clear pattern was identified in {delta}{sup 15}N, while an increasing effect of the fossil fuel dilution on the atmospheric bomb-enriched {sup 14}C background was detected in tree rings, possibly as a consequence of the increase in traffic exhausts. Our findings suggested that radiocarbon is a very sensitive tool to investigate small-scale (i.e. traffic exhaust at the level crossing) and large-scale (urban area pollution) induced disturbances.

  19. Ranking of tree-ring based temperature reconstructions of the past millennium

    Science.gov (United States)

    Esper, Jan; Krusic, Paul J.; Ljungqvist, Fredrik C.; Luterbacher, Jürg; Carrer, Marco; Cook, Ed; Davi, Nicole K.; Hartl-Meier, Claudia; Kirdyanov, Alexander; Konter, Oliver; Myglan, Vladimir; Timonen, Mauri; Treydte, Kerstin; Trouet, Valerie; Villalba, Ricardo; Yang, Bao; Büntgen, Ulf

    2016-08-01

    Tree-ring chronologies are widely used to reconstruct high-to low-frequency variations in growing season temperatures over centuries to millennia. The relevance of these timeseries in large-scale climate reconstructions is often determined by the strength of their correlation against instrumental temperature data. However, this single criterion ignores several important quantitative and qualitative characteristics of tree-ring chronologies. Those characteristics are (i) data homogeneity, (ii) sample replication, (iii) growth coherence, (iv) chronology development, and (v) climate signal including the correlation with instrumental data. Based on these 5 characteristics, a reconstruction-scoring scheme is proposed and applied to 39 published, millennial-length temperature reconstructions from Asia, Europe, North America, and the Southern Hemisphere. Results reveal no reconstruction scores highest in every category and each has their own strengths and weaknesses. Reconstructions that perform better overall include N-Scan and Finland from Europe, E-Canada from North America, Yamal and Dzhelo from Asia. Reconstructions performing less well include W-Himalaya and Karakorum from Asia, Tatra and S-Finland from Europe, and Great Basin from North America. By providing a comprehensive set of criteria to evaluate tree-ring chronologies we hope to improve the development of large-scale temperature reconstructions spanning the past millennium. All reconstructions and their corresponding scores are provided at http://www.blogs.uni-mainz.de/fb09climatology.

  20. Climate reconstructions from tree-ring widths for the last 850 years in Northern Poland

    Science.gov (United States)

    Heinrich, Ingo; Knorr, Antje; Heußner, Karl-Uwe; Wazny, Tomasz; Slowinski, Michal; Helle, Gerhard; Simard, Sonia; Scharnweber, Tobias; Buras, Allan; Beck, Wolfgang; Wilmking, Martin; Brauer, Achim

    2015-04-01

    Tree-ring based temperature reconstructions form the scientific backbone of the current debate over global change, and they are the major part of the palaeo data base used for the IPCC report. However, long temperature reconstructions derived from temperate lowland trees growing well within their distributional limits in central Europe are not part of the IPCC report, which is an essential gap in the international data base. It appears that dendroclimatological analysis at temperate lowland sites was so far difficult to perform mainly for three reasons: diffuse climate-growth relationships, the lack of long chronologies due to absence of sufficient numbers of long-living trees and the potential loss of low-frequency signals due to the short length of the sample segments. We present two robust multi-centennial reconstructions of winter temperatures and summer precipitation based on pine and oak tree-ring widths chronologies from northern Poland, where so far no long tree-ring based reconstructions were available. We compared the new records with global, hemispherical and regional reconstructions, and found good agreement with some of them. In comparison, the winter temperature of our reconstruction, however, did not indicate any modern warming nor did the summer precipitation reconstruction suggest any modern 20th century changes. In a second step, we measured cell structures and developed chronologies of parameters such as cell wall thickness and cell lumen area. We used our new method (Liang et al. 2013a,b) applying confocal laser scanning microscopy to increment core surfaces for efficient histometric analyses. We focused on samples covering the last century because meteorological data necessary for calibration studies were available for direct comparisons. It was demonstrated that the correlations with climate were strong and different from those found for tree-ring widths (e.g., N-Poland oak-vessel-lumen-area-chronology with previous September-to-December mean

  1. UV-laser-based microscopic dissection of tree rings - a novel sampling tool for δ(13) C and δ(18) O studies.

    Science.gov (United States)

    Schollaen, Karina; Heinrich, Ingo; Helle, Gerhard

    2014-02-01

    UV-laser-based microscopic systems were utilized to dissect and sample organic tissue for stable isotope measurements from thin wood cross-sections. We tested UV-laser-based microscopic tissue dissection in practice for high-resolution isotopic analyses (δ(13) C/δ(18) O) on thin cross-sections from different tree species. The method allows serial isolation of tissue of any shape and from millimetre down to micrometre scales. On-screen pre-defined areas of interest were automatically dissected and collected for mass spectrometric analysis. Three examples of high-resolution isotopic analyses revealed that: in comparison to δ(13) C of xylem cells, woody ray parenchyma of deciduous trees have the same year-to-year variability, but reveal offsets that are opposite in sign depending on whether wholewood or cellulose is considered; high-resolution tree-ring δ(18) O profiles of Indonesian teak reflect monsoonal rainfall patterns and are sensitive to rainfall extremes caused by ENSO; and seasonal moisture signals in intra-tree-ring δ(18) O of white pine are weighted by nonlinear intra-annual growth dynamics. The applications demonstrate that the use of UV-laser-based microscopic dissection allows for sampling plant tissue at ultrahigh resolution and unprecedented precision. This new technique facilitates sampling for stable isotope analysis of anatomical plant traits like combined tree eco-physiological, wood anatomical and dendroclimatological studies. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  2. Stable Ca Isotopes in Tamarix aphylla Tree Rings, Death Valley, California

    Science.gov (United States)

    Yang, W.; Depaolo, D. J.; Ingram, B. L.; Owens, T. L.

    2008-12-01

    As a dune stabilizer and windbreak, Tamarix aphylla is an exotic perennial and evergreen tree in Death Valley. Its tap roots can reach down to 30 m depth and sub-superficial side roots may reach 50 m horizontally. The species can store large amounts of water in its roots and undergoes high evapotranspiration. Since Tamarix aphylla is a perennial tree growing in desert environments and its roots reach deep to the water table, it could be a proxy for desert ecological and hydrologic systems through time. We measured Ca isotopes in the soluble fraction of 8 tree ring samples from a 50-year-old specimen growing on an alluvial fan in Death Valley near Furnace Creek. Previous studies (Yang et al, GCA 60, 1996) indicate that this tree's rings contain high sulfur concentrations (4-6% expressed as sulfate) with chemical composition of CaSO4 (0.15-0.62 H2O). The δ34S values of soluble sulfate increase from +13.5 to +18 permil VCDT from the core to the bark, which are interpreted as reflecting deeper sulfate sources as the tree grew. The δ13C variations of the tree-ring cellulose (-27.6 to -24.0 permil VPDB) reflect changes in the local precipitation and show that Tamarix aphylla undergoes C3 photosynthesis. The δ44Ca for the soluble sulfate Ca through the tree-ring section, which covers a time period from 1945 to 1993, have an average value -2.52 permil (-3.4 permil relative to seawater). Only small variations are observed, from -2.69 to -2.28; the highest value (for 1990) occurs near the end of an extended drought. These are the first measurements of tree rings, but the low δ44Ca values are consistent with previous measurements of beech roots and stems from a temperate forest (Page et al., Biogeochem. 88, 2008). In our case, the tree has only one Ca source, which is expected to be isotopically uniform and similar to both local rainfall and limestones (δ44Ca ~ -0.6 permil), and with the minimal vegetation and extensive deep root system it is unlikely that there is a

  3. A 300-year history of Pacific Northwest windstorms inferred from tree rings

    Science.gov (United States)

    Knapp, Paul A.; Hadley, Keith S.

    2012-07-01

    Hurricane-force winds are frequently allied with mid-latitude cyclones yet little is known about their historical timing and geographic extent over multiple centuries. This research addresses these issues by extending the historical record of major mid-latitude windstorms along North America's Pacific Northwest (PNW) coast using tree-ring data collected from old-growth (> 350 years), wind-snapped trees sampled at seven coastal sites in Oregon, USA. Our objectives were to: 1) characterize historical windstorm regimes; 2) determine the relationship between high-wind events (HWEs) and phases of the PDO, ENSO and NPI; and 3) test the hypothesis that PNW HWEs have migrated northward. We based our study on the identification of tree-growth anomalies resulting from windstorm-induced canopy changes corresponding to documented (1880-2003) and projected HWEs (1701-1880). Our methods identified all major windstorm events recorded since the late 1800s and confirmed that variations in coastal tree-growth are weakly related to temperature, precipitation, and drought, but are significantly related to peak wind speeds. These results suggest wind-induced changes in canopy conditions control tree growth at all sites. Comparisons between the tree-ring record and the PDO, NPI, and ENSO revealed a significant positive correlation between HWEs and neutral to warm PDO conditions and a slightly weaker correlation with the NPI. ENSO events were not significantly related to the occurrence of HWEs. Latitudinal groupings of our sites revealed a gradual and non-significant northerly shift of HWEs until the late 19th century followed by a significant northward shift during the past 120 years. These results mark the application of dendroanemology as a method for characterizing windstorm regimes for multiple centuries.

  4. A technical perspective in modern tree-ring research--how to overcome dendroecological and wood anatomical challenges.

    Science.gov (United States)

    Gärtner, Holger; Cherubini, Paolo; Fonti, Patrick; von Arx, Georg; Schneider, Loïc; Nievergelt, Daniel; Verstege, Anne; Bast, Alexander; Schweingruber, Fritz H; Büntgen, Ulf

    2015-03-05

    Dendroecological research uses information stored in tree rings to understand how single trees and even entire forest ecosystems responded to environmental changes and to finally reconstruct such changes. This is done by analyzing growth variations back in time and correlating various plant-specific parameters to (for example) temperature records. Integrating wood anatomical parameters in these analyses would strengthen reconstructions, even down to intra-annual resolution. We therefore present a protocol on how to sample, prepare, and analyze wooden specimen for common macroscopic analyses, but also for subsequent microscopic analyses. Furthermore we introduce a potential solution for analyzing digital images generated from common small and large specimens to support time-series analyses. The protocol presents the basic steps as they currently can be used. Beyond this, there is an ongoing need for the improvement of existing techniques, and development of new techniques, to record and quantify past and ongoing environmental processes. Traditional wood anatomical research needs to be expanded to include ecological information to this field of research. This would support dendro-scientists who intend to analyze new parameters and develop new methodologies to understand the short and long term effects of specific environmental factors on the anatomy of woody plants.

  5. Tree-ring chronologies and stable carbon isotopic composition reveal impacts of hydro-climate change on bottomland hardwood forests of South-Central Texas

    Science.gov (United States)

    Deshpande, A. G.; Lafon, C. W.; Hyodo, A.; Boutton, T. W.; Moore, G. W.

    2017-12-01

    Over the last three decades, South-Central Texas has experienced an increase in frequency and intensity of hydro-climatic anomalies such as extreme droughts and floods. These extreme events can have negative impacts on forest health and can strongly alter a wide range of ecosystem processes. Tree increment growth in bottomland hardwood forests is influenced by droughts and floods, which affects the carbon isotope values (δ13C) in tree-ring cellulose. This study aims to assess the impacts of hydro-climate change on the growth and physiological response of bottomland hardwood forests by investigating variations in radial growth and tree-ring carbon isotopic composition. Annual ring-width chronologies for 41 years (1975-2016) were developed from 24 water oak (Quercus nigra) trees at 4 sites along a 25 km transect located in the San Bernard River watershed. The δ13C values in cellulose were measured from 4-year ring composites including years with anomalously high and low precipitation. Dendroclimatology analysis involved correlating ring-width index with precipitation records and Palmer Drought Sensitivity Index (PDSI). Radial growth was more closely associated with spring-summer (Feb-Aug) precipitation (R2 = 0.42, pstress, as indicated by narrower growth rings and increased cellulose δ13C. However, the inter-site variation in δ13C indicated large hydro-climatic variation between sites (2.79-4.24‰ for wet years and 0.53-1.50‰ for drought years). δ13C values showed an increase of 0.78‰ and 2.40‰ from the wettest (1991-1994) to the driest period (2008-2011) at two of our sites, possibly due to drought-induced moisture-deficit-stress. However, at the other two sites, the δ13C values of tree rings from the same periods decreased by 0.65‰ and 1.19‰, possibly emanating from flooding-induced stress caused by waterlogging. This study provides insights on how hydro-climatic variations affect riparian forest health in the region and acts as a baseline for

  6. Seasonal climate signals from multiple tree ring metrics: A case study of Pinus ponderosa in the upper Columbia River Basin

    Science.gov (United States)

    Dannenberg, Matthew P.; Wise, Erika K.

    2016-04-01

    Projected changes in the seasonality of hydroclimatic regimes are likely to have important implications for water resources and terrestrial ecosystems in the U.S. Pacific Northwest. The tree ring record, which has frequently been used to position recent changes in a longer-term context, typically relies on signals embedded in the total ring width of tree rings. Additional climatic inferences at a subannual temporal scale can be made using alternative tree ring metrics such as earlywood and latewood widths and the density of tree ring latewood. Here we examine seasonal precipitation and temperature signals embedded in total ring width, earlywood width, adjusted latewood width, and blue intensity chronologies from a network of six Pinus ponderosa sites in and surrounding the upper Columbia River Basin of the U.S. Pacific Northwest. We also evaluate the potential for combining multiple tree ring metrics together in reconstructions of past cool- and warm-season precipitation. The common signal among all metrics and sites is related to warm-season precipitation. Earlywood and latewood widths differ primarily in their sensitivity to conditions in the year prior to growth. Total and earlywood widths from the lowest elevation sites also reflect cool-season moisture. Effective correlation analyses and composite-plus-scale tests suggest that combining multiple tree ring metrics together may improve reconstructions of warm-season precipitation. For cool-season precipitation, total ring width alone explains more variance than any other individual metric or combination of metrics. The composite-plus-scale tests show that variance-scaled precipitation reconstructions in the upper Columbia River Basin may be asymmetric in their ability to capture extreme events.

  7. A 9111 year long conifer tree-ring chronology for the European Alps : a base for environmental and climatic investigations

    NARCIS (Netherlands)

    Nicolussi, K.; Kaufmann, M.; Melvin, Thomas M.; van der Plicht, J.; Schiessling, P.; Thurner, A.

    An ultra-long tree-ring width chronology (9111 years long, 7109 BC to AD 2002) has been established based on the analysis and dating of 1432 subfossil/dry dead wood samples and cores from 335 living trees. The material was collected from treeline or near-treeline sites (c. 2000 to 2400 m a.s.l.)

  8. Content of chemical elements in tree rings of lodgepole pine and whitebark pine from a subalpine Sierra Nevada forest

    Science.gov (United States)

    David L. Peterson; Darren R. Anderson

    1990-01-01

    The wood of lodgepole pines and whitebark pines from a high elevation site in the east central Sierra Nevada of California was analyzed for chemical content to determine whether there were any temporal patterns of chemical distribution in tree rings. Cores were taken from 10 trees of each species and divided into 5-year increments for chemical analysis. Correlation...

  9. The Reconstruction Potential of a 350 year-long, Mid-Elevation Proxy for PDSI in a Tree-Ring Record from Tropical North Queensland, Australia.

    Science.gov (United States)

    English, N. B.; Duffy, R.; Balanzategui, D.; Baker, P. J.; Evans, M. N.

    2014-12-01

    In far northern Queensland (FNQ) there are only sporadic coral and speleothem precipitation proxy records, and only one annually resolved, terrestrial record of rainfall that predates 1850 CE. Black kauri pine, Agathis atropurpurea, is a large conifer present in isolated stands near 1000 masl in the wet tropical dividing range of FNQ. Little is known about its phenology or responses to climate, although its presence near the elevational limit of the dividing range may hinder its ability to respond to increased temperature or decreased precipitation through elevational migration. We hypothesize that in this energy-limited forest, increased (decreased) solar radiation leads to increased (decreased) ring widths, and higher (lower) evapotranspiration rates produce increases (decreases) in the oxygen isotopic composition (δ18O) of the a-cellulose component of wood. To test this hypothesis, we collected over 60 cores from 21 large (dbh = 56 to 186 cm) A. atropurpurea trees from Spurgeon Peak National Park. The resulting tree-ring chronology extends from 2013 to 1438 CE and shows high average mean sensitivity (0.642) although expressed population signal drops off at 1650 CE as sample depth decreases. Comparison of the most recent 100 years of ring widths and direct climate observations show a significant positive relationship (r2 = 0.4, p < 0.01) to PDSI in December through March, coinciding with the austral rainy season associated with onset of the northern Australian Monsoon. Annualized δ18Oxygen (a-cellulose) maxima for 1983-2013 show strong and significant spatial positive relationships to Tmax and Pacific seasurface temperatures. Work to refine the interpretation of the data is onoing, but the resulting dataset may enable extension of the terrestrial climate record of north Queensland two centuries beyond current tree-ring proxies and historical observations.

  10. Spatial and temporal variation in tree-ring α-cellulose oxygen and hydrogen isotope values as a record of water availability in the Atacama Desert

    Science.gov (United States)

    Olson, E. J.; Dodd, J. P.

    2015-12-01

    Previous studies have documented that tree ring oxygen and hydrogen isotopes primarily reflect source water; however, biosynthetic fractionation processes modify this signal and can have a varied response to environmental conditions. The degree to which source water contributes to δ2H and δ18O values of plant α-cellulose is species-specific and modern calibration studies are necessary. Here we present a calibration data set of P. tamarugo α-cellulose δ2H and δ18O values from the Atacama Desert in Northern Chile. P. tamarugo trees are endemic to the region and have adapted to the extremely arid environment where average annual precipitation is 2 ‰ over the past 20 years associated with a ~1.1 m lowering of the local groundwater table throughout the area. The correlation between a-cellulose isotope values and hydrologic conditions in modern times provides a baseline for interpretation of tree-ring isotope chronologies from the past 9.5 kya. A high-resolution Holocene (1.8-9.1 kya) age record of Prosopis sp. tree ring α-cellulose δ18O values provides a proxy for climatic and hydrologic conditions. During the early Holocene δ18O values range from 31 to 35‰ (2σ=0.58‰), while during the late Holocene values are much more variable (27.4 to 41‰; 2σ=2.64‰). Anthropogenic demand on local water sources is the most significant environmental factor affecting the variation in modern α-cellulose δ18O values; however, climate induced changes in regional water availability are the dominant driver of variability in the paleo-record. Increased variability in α-cellulose δ18O values in the late Holocene most likely indicates a reduction in annual recharge and an increase in episodic flood events driven by ENSO and other modes of atmospheric variability.

  11. Reconstructions of Columbia River streamflow from tree-ring chronologies in the Pacific Northwest, USA

    Science.gov (United States)

    Littell, Jeremy; Pederson, Gregory T.; Gray, Stephen T.; Tjoelker, Michael; Hamlet, Alan F.; Woodhouse, Connie A.

    2016-01-01

    We developed Columbia River streamflow reconstructions using a network of existing, new, and updated tree-ring records sensitive to the main climatic factors governing discharge. Reconstruction quality is enhanced by incorporating tree-ring chronologies where high snowpack limits growth, which better represent the contribution of cool-season precipitation to flow than chronologies from trees positively sensitive to hydroclimate alone. The best performing reconstruction (back to 1609 CE) explains 59% of the historical variability and the longest reconstruction (back to 1502 CE) explains 52% of the variability. Droughts similar to the high-intensity, long-duration low flows observed during the 1920s and 1940s are rare, but occurred in the early 1500s and 1630s-1640s. The lowest Columbia flow events appear to be reflected in chronologies both positively and negatively related to streamflow, implying low snowpack and possibly low warm-season precipitation. High flows of magnitudes observed in the instrumental record appear to have been relatively common, and high flows from the 1680s to 1740s exceeded the magnitude and duration of observed wet periods in the late-19th and 20th Century. Comparisons between the Columbia River reconstructions and future projections of streamflow derived from global climate and hydrologic models show the potential for increased hydrologic variability, which could present challenges for managing water in the face of competing demands

  12. A 400-year tree-ring chronology from the tropical treeline of North America.

    Science.gov (United States)

    Biondi, F

    2001-05-01

    High-elevation sites in the tropics may be particularly sensitive to rapid climate change. By sampling treeline populations, I have developed the first extensive (> 300 years) tree-ring chronology in tropical North America. The site is Nevado de Colima, at the western end of the Mexican Neovolcanic Belt, and the species studied is Mexican mountain pine (Pinus hartwegii). Despite past logging in the area, 300 to 500-year old pines were found at 3600-3700 m elevation, about 300 m below the present treeline. The Nevado de Colima tree-ring chronology is well replicated from 1600 to 1997. Calibration with Colima climatic records points to summer monsoon precipitation as the strongest dendroclimatic signal. Most trees also exhibit extremely low growth in 1913 and 1914, following the January 1913 Plinian eruption of the Volcan de Colima. Because P. hartwegii is found on top of high mountains from Mexico to Guatemala, there is potential for developing a network of tropical treeline chronologies.

  13. Multiple bands characteristics of tree-ring and age of haloxylon ammodendron in gurbantunggut desert

    International Nuclear Information System (INIS)

    Song, Y.; Zhou, C.

    2015-01-01

    The characteristics of the multiple bands of Haloxylon ammodendron (C.A. Mey) Bunge tree-ring were studied in three edaphic types. Age equations were derived relating ground diameter and tree height, and the effects of irrigation on numbers and widths of growth bands at the longest radius were analyzed. Results showed that the number of growth bands ranged from 3.3 to 6.3 per year, the widths ranged between 0.181 mm and 0.473 mm. Multiple growth bands formed every growing season, leading to the conclusion that multiple growth bands in H. ammodendron tree-ring are a natural feature. A dark brown layer and a light brown one make up one growth band. The dark brown layers consists of fibres and vessels as well as some ray parenchyma, and each fibres layers with 22-35 cell layers; the light brown layers formed by vessels, fibres and abundant paratracheal axial parenchyma are 4-15 cell layers. The widths of growth bands at the longest radius increased significantly as the irrigation amount increased in three edaphic types (p<0.01). The numbers of growth bands at the longest radius had significant positive correlation with irrigation times. The ratio of dark brown layers to light brown layers of growth bands at the longest radius appeared to have a rising tendency with the increase in irrigation amount and times. (author)

  14. Biogeochemical modelling vs. tree-ring data - comparison of forest ecosystem productivity estimates

    Science.gov (United States)

    Zorana Ostrogović Sever, Maša; Barcza, Zoltán; Hidy, Dóra; Paladinić, Elvis; Kern, Anikó; Marjanović, Hrvoje

    2017-04-01

    Forest ecosystems are sensitive to environmental changes as well as human-induce disturbances, therefore process-based models with integrated management modules represent valuable tool for estimating and forecasting forest ecosystem productivity under changing conditions. Biogeochemical model Biome-BGC simulates carbon, nitrogen and water fluxes, and it is widely used for different terrestrial ecosystems. It was modified and parameterised by many researchers in the past to meet the specific local conditions. In this research, we used recently published improved version of the model Biome-BGCMuSo (BBGCMuSo), with multilayer soil module and integrated management module. The aim of our research is to validate modelling results of forest ecosystem productivity (NPP) from BBGCMuSo model with observed productivity estimated from an extensive dataset of tree-rings. The research was conducted in two distinct forest complexes of managed Pedunculate oak in SE Europe (Croatia), namely Pokupsko basin and Spačva basin. First, we parameterized BBGCMuSo model at a local level using eddy-covariance (EC) data from Jastrebarsko EC site. Parameterized model was used for the assessment of productivity on a larger scale. Results of NPP assessment with BBGCMuSo are compared with NPP estimated from tree ring data taken from trees on over 100 plots in both forest complexes. Keywords: Biome-BGCMuSo, forest productivity, model parameterization, NPP, Pedunculate oak

  15. A simple program to measure and analyse tree rings using Excel, R and SigmaScan

    Science.gov (United States)

    Hietz, Peter

    2011-01-01

    I present a new software that links a program for image analysis (SigmaScan), one for spreadsheets (Excel) and one for statistical analysis (R) for applications of tree-ring analysis. The first macro measures ring width marked by the user on scanned images, stores raw and detrended data in Excel and calculates the distance to the pith and inter-series correlations. A second macro measures darkness along a defined path to identify latewood–earlywood transition in conifers, and a third shows the potential for automatic detection of boundaries. Written in Visual Basic for Applications, the code makes use of the advantages of existing programs and is consequently very economic and relatively simple to adjust to the requirements of specific projects or to expand making use of already available code. PMID:26109835

  16. A sub-fossil kauri (Agathis australis) tree-ring chronology

    International Nuclear Information System (INIS)

    Bridge, M.C.; Ogden, J.

    1986-01-01

    A 491-year floating tree-ring chronology was constructed using sub-fossil bog kauris, Agathis australis, from a site near Huntly, North Island, New Zealand. The chronology has been approximately dated to within the period 3,500 B.P. to 3,000 B.P. by radiocarbon dating. This is the first sub-fossil New Zealand chronology, and shows the potential for the formation of a long chronology from the present back over several millenia. The applications of this chronology and its possible extensions include radiocarbon calibration for the Southern Hemisphere, and climatic reconstructions based on ring-widths. It will also assist interpretation of the history of the Waikato Valley over the last few millenia

  17. A simple program to measure and analyse tree rings using Excel, R and SigmaScan.

    Science.gov (United States)

    Hietz, Peter

    I present a new software that links a program for image analysis (SigmaScan), one for spreadsheets (Excel) and one for statistical analysis (R) for applications of tree-ring analysis. The first macro measures ring width marked by the user on scanned images, stores raw and detrended data in Excel and calculates the distance to the pith and inter-series correlations. A second macro measures darkness along a defined path to identify latewood-earlywood transition in conifers, and a third shows the potential for automatic detection of boundaries. Written in Visual Basic for Applications, the code makes use of the advantages of existing programs and is consequently very economic and relatively simple to adjust to the requirements of specific projects or to expand making use of already available code.

  18. Potential for tree rings to reveal spatial patterns of past drought variability across western Australia

    Science.gov (United States)

    O'Donnell, Alison J.; Cook, Edward R.; Palmer, Jonathan G.; Turney, Chris S. M.; Grierson, Pauline F.

    2018-02-01

    Proxy records have provided major insights into the variability of past climates over long timescales. However, for much of the Southern Hemisphere, the ability to identify spatial patterns of past climatic variability is constrained by the sparse distribution of proxy records. This is particularly true for mainland Australia, where relatively few proxy records are located. Here, we (1) assess the potential to use existing proxy records in the Australasian region—starting with the only two multi-century tree-ring proxies from mainland Australia—to reveal spatial patterns of past hydroclimatic variability across the western third of the continent, and (2) identify strategic locations to target for the development of new proxy records. We show that the two existing tree-ring records allow robust reconstructions of past hydroclimatic variability over spatially broad areas (i.e. > 3° × 3°) in inland north- and south-western Australia. Our results reveal synchronous periods of drought and wet conditions between the inland northern and southern regions of western Australia as well as a generally anti-phase relationship with hydroclimate in eastern Australia over the last two centuries. The inclusion of 174 tree-ring proxy records from Tasmania, New Zealand and Indonesia and a coral record from Queensland did not improve the reconstruction potential over western Australia. However, our findings suggest that the addition of relatively few new proxy records from key locations in western Australia that currently have low reconstruction skill will enable the development of a comprehensive drought atlas for the region, and provide a critical link to the drought atlases of monsoonal Asia and eastern Australia and New Zealand.

  19. Volcano-induced regime shifts in millennial tree-ring chronologies from northeastern North America.

    Science.gov (United States)

    Gennaretti, Fabio; Arseneault, Dominique; Nicault, Antoine; Perreault, Luc; Bégin, Yves

    2014-07-15

    Dated records of ice-cap growth from Arctic Canada recently suggested that a succession of strong volcanic eruptions forced an abrupt onset of the Little Ice Age between A.D. 1275 and 1300 [Miller GH, et al. (2012) Geophys Res Lett 39(2):L02708, 10.1029/2011GL050168]. Although this idea is supported by simulation experiments with general circulation models, additional support from field data are limited. In particular, the Northern Hemisphere network of temperature-sensitive millennial tree-ring chronologies, which principally comprises Eurasian sites, suggests that the strongest eruptions only caused cooling episodes lasting less than about 10 y. Here we present a new network of millennial tree-ring chronologies from the taiga of northeastern North America, which fills a wide gap in the network of the Northern Hemisphere's chronologies suitable for temperature reconstructions and supports the hypothesis that volcanoes triggered both the onset and the coldest episode of the Little Ice Age. Following the well-expressed Medieval Climate Anomaly (approximately A.D. 910-1257), which comprised the warmest decades of the last millennium, our tree-ring-based temperature reconstruction displays an abrupt regime shift toward lower average summer temperatures precisely coinciding with a series of 13th century eruptions centered around the 1257 Samalas event and closely preceding ice-cap expansion in Arctic Canada. Furthermore, the successive 1809 (unknown volcano) and 1815 (Tambora) eruptions triggered a subsequent shift to the coldest 40-y period of the last 1100 y. These results confirm that series of large eruptions may cause region-specific regime shifts in the climate system and that the climate of northeastern North America is especially sensitive to volcanic forcing.

  20. Carbon stable isotope-climate association in tree rings of Pinus pinaster and Pinus sylvestris in Mediterranean environments

    International Nuclear Information System (INIS)

    Bogino, Stella M; Bravo, Felipe

    2014-01-01

    Carbon isotope ratios, recorded as "1"3C/"1"2C variations in tree rings of woody species, are the result of physiological changes related to environmental conditions. The objective of this work was to analyze the association among carbon thirteen variability (δ"1"3C), climate variables and tree-ring growth of Pinus pinaster and Pinus sylvestris in central Spain. Pulverized woody material from the period 1975-1999 from four trees for each pine species was analyzed. To detect common patterns in δ"1"3C within each species and between δ"1"3C and growth indices, a principal component analysis (PCA) was performed. δ"1"3C of trees and the residual tree-ring chronologies were used at the PCA. Multilevel mixed linear models were applied between intrinsic water use efficiency (iWUE) and climate variables. Our results show an inverse significant correlation between δ"1"3C and tree-ring growth of both species. Winter and spring air moisture was negatively correlated with iWUE of Pinus pinaster. July maximum temperature was positively correlated with iWUE of Pinus sylvestris. As δ"1"3C is significantly related to climate and growth and it may be recommended as a valuable tool for tree growth dynamic analysis to withstand increasingly stressful climate conditions

  1. Tree growth and its climate signal along latitudinal and altitudinal gradients: comparison of tree rings between Finland and the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    L. Lyu

    2017-06-01

    Full Text Available Latitudinal and altitudinal gradients can be utilized to forecast the impact of climate change on forests. To improve the understanding of how these gradients impact forest dynamics, we tested two hypotheses: (1 the change of the tree growth–climate relationship is similar along both latitudinal and altitudinal gradients, and (2 the time periods during which climate affects growth the most occur later towards higher latitudes and altitudes. To address this, we utilized tree-ring data from a latitudinal gradient in Finland and from two altitudinal gradients on the Tibetan Plateau. We analysed the latitudinal and altitudinal growth patterns in tree rings and investigated the growth–climate relationship of trees by correlating ring-width index chronologies with climate variables, calculating with flexible time windows, and using daily-resolution climate data. High latitude and altitude plots showed higher correlations between tree-ring chronologies and growing season temperature. However, the effects of winter temperature showed contrasting patterns for the gradients. The timing of the highest correlation with temperatures during the growing season at southern sites was approximately 1 month ahead of that at northern sites in the latitudinal gradient. In one out of two altitudinal gradients, the timing for the strongest negative correlation with temperature at low-altitude sites was ahead of treeline sites during the growing season, possibly due to differences in moisture limitation. Mean values and the standard deviation of tree-ring width increased with increasing mean July temperatures on both types of gradients. Our results showed similarities of tree growth responses to increasing seasonal temperature between latitudinal and altitudinal gradients. However, differences in climate–growth relationships were also found between gradients due to differences in other factors such as moisture conditions. Changes in the timing of the most

  2. Isotope Reanalysis for 20th century: Reproduction of isotopic time series in corals, tree-rings, and tropical ice cores

    Science.gov (United States)

    Yoshimura, K.

    2012-04-01

    In the present study, an isotope-incorporated GCM simulation for AD1871 to AD2008 nudged toward the so-called "20th Century Reanalysis (20CR)" atmospheric fields is conducted. Beforehand the long-term integration, a method to downscale ensemble mean fields is proposed, since 20CR is a product of 56-member ensemble Kalman filtering data assimilation. The method applies a correction to one of the ensemble members in such a way that the seasonal mean is equal to that of the ensemble mean, and then the corrected member is inputted into the isotope-incorporated GCM (i.e., IsoGSM) with the global spectral nudging technique. Use of the method clearly improves the skill than the cases of using only a single member and of using the ensemble means; the skill becomes equivalent to when 3-6 members are directly used. By comparing with GNIP precipitation isotope database, it is confirmed that the 20C Isotope Reanalysis's performance for latter half of the 20th century is just comparable to the other latest studies. For more comparisons for older periods, proxy records including corals, tree-rings, and tropical ice cores are used. First for corals: the 20C Isotope Reanalysis successfully reproduced the δ18O in surface sea water recorded in the corals at many sites covering large parts of global tropical oceans. The comparison suggests that coral records represent past hydrologic balance information where interannual variability in precipitation is large. Secondly for tree-rings: δ18O of cellulose extracted from the annual rings of the long-lived Bristlecone Pine from White Mountain in Southern California is well reproduced by 20C Isotope Reanalysis. Similar good performance is obtained for Cambodia, too. However, the mechanisms driving the isotopic variations are different over California and Cambodia; for California, Hadley cell's expansion and consequent meridional shift of the submerging dry zone and changes in water vapor source is the dominant control, but in Cambodia

  3. Characteristics of high-purity Teflon vial for 14C measurement in old tree rings

    International Nuclear Information System (INIS)

    Sakurai, H.; Saswaki, Y.; Matsumoto, T.; Aoki, T.; Kato, W.; Gandou, T.; Gunji, S.; Tokanai, F.

    2003-01-01

    14 C concentration in single-year tree rings of an old cedar of ca. 2500 years ago is measured to investigate the 11-yr periodicity of solar activity. Our highly accurate 14 C measuring system is composed of a benzene synthesizer capable of producing a large quantity (10 g) of benzene and a Quantulus 1220 TM liquid scintillation counting system. The accuracy is less than 0.2% for measurements of 14 C concentration. The benzene sample is contained in a high-purity Teflon/copper-counting vial (20 ml) manufactured by Wallac Oy Company. We found a vial with an irregular copper cap for the measurements of 11 tree rings. The behavior of the vial with the irregular cap was investigated. The Teflon sheet inside the cap plays an important role in achieving stable measurement. The rate of volatilization of the benzene was less than 0.35 mg/day for vials with ordinary caps. This results in the volatilization rate of 0.003% for 10.5 g of benzene and hence guarantees measurement at an accuracy of 0.2% for 70 days

  4. Runoff variations in Lake Balkhash Basin, Central Asia, 1779-2015, inferred from tree rings

    Science.gov (United States)

    Panyushkina, Irina P.; Meko, D. M.; Macklin, M. G.; Toonen, W. H. J.; Mukhamadiev, N. S.; Konovalov, V. G.; Ashikbaev, N. Z.; Sagitov, A. O.

    2018-01-01

    Long highly-resolved proxies for runoff are in high demand for hydrological forecasts and water management in arid Central Asia. An accurate (R2 = 0.53) reconstruction of October-September discharge of the Ili River in Kazakhstan, 1779-2015, is developed from moisture-sensitive tree rings of spruce sampled in the Tian Shan Mountains. The fivefold extension of the gauged discharge record represents the variability of runoff in the Lake Balkhash Basin for the last 235 years. The reconstruction shows a 40 year long interval of low discharge preceded a recent high peak in the first decade of the 2000s followed by a decline to more recent levels of discharge not seen since the start of the gauged record. Most reconstructed flow extremes (± 2σ) occur outside the instrumental record (1936-2015) and predate the start of large dam construction (1969). Decadal variability of the Ili discharge corresponds well with hydrological records of other Eurasian internal drainages modeled with tree rings. Spectral analysis identifies variance peaks (highest near 42 year) consistent with main hemispheric oscillations of the Eurasian climatic system. Seasonal comparison of the Ili discharge with sea-level-pressure and geopotential height data suggests periods of high flow likely result from the increased contribution of snow to runoff associated with the interaction of Arctic air circulation with the Siberian High-Pressure System and North Atlantic Oscillation.

  5. Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes

    Science.gov (United States)

    Salzer, Matthew W.; Hughes, Malcolm K.; Bunn, Andrew G.; Kipfmueller, Kurt F.

    2009-01-01

    Great Basin bristlecone pine (Pinus longaeva) at 3 sites in western North America near the upper elevation limit of tree growth showed ring growth in the second half of the 20th century that was greater than during any other 50-year period in the last 3,700 years. The accelerated growth is suggestive of an environmental change unprecedented in millennia. The high growth is not overestimated because of standardization techniques, and it is unlikely that it is a result of a change in tree growth form or that it is predominantly caused by CO2 fertilization. The growth surge has occurred only in a limited elevational band within ≈150 m of upper treeline, regardless of treeline elevation. Both an independent proxy record of temperature and high-elevation meteorological temperature data are positively and significantly correlated with upper-treeline ring width both before and during the high-growth interval. Increasing temperature at high elevations is likely a prominent factor in the modern unprecedented level of growth for Pinus longaeva at these sites. PMID:19918054

  6. SNOW AVALANCHE ACTIVITY IN PARÂNG SKI AREA REVEALED BY TREE-RINGS

    Directory of Open Access Journals (Sweden)

    F. MESEȘAN

    2014-11-01

    Full Text Available Snow Avalanche Activity in Parâng Ski Area Revealed by Tree-Rings. Snow avalanches hold favorable conditions to manifest in Parâng Mountains but only one event is historically known, without destructive impact upon infrastructure or fatalities and this region wasn’t yet the object of avalanche research. The existing ski infrastructure of Parâng resort located in the west of Parâng Mountains is proposed to be extended in the steep slopes of subalpine area. Field evidence pinpoints that these steep slopes were affected by snow avalanches in the past. In this study we analyzed 11 stem discs and 31 increment cores extracted from 22 spruces (Picea abies (L. Karst impacted by avalanches, in order to obtain more information about past avalanches activity. Using the dendrogeomorphological approach we found 13 avalanche events that occurred along Scărița avalanche path, since 1935 until 2012, nine of them produced in the last 20 years. The tree-rings data inferred an intense snow avalanche activity along this avalanche path. This study not only calls for more research in the study area but also proves that snow avalanches could constitute an important restrictive factor for the tourism infrastructure and related activities in the area. It must be taken into consideration by the future extension of tourism infrastructure. Keywords: snow avalanche, Parâng Mountains, dendrogeomorphology, ski area.

  7. Bayesian neural network modeling of tree-ring temperature variability record from the Western Himalayas

    Directory of Open Access Journals (Sweden)

    R. K. Tiwari

    2011-08-01

    Full Text Available A novel technique based on the Bayesian neural network (BNN theory is developed and employed to model the temperature variation record from the Western Himalayas. In order to estimate an a posteriori probability function, the BNN is trained with the Hybrid Monte Carlo (HMC/Markov Chain Monte Carlo (MCMC simulations algorithm. The efficacy of the new algorithm is tested on the well known chaotic, first order autoregressive (AR and random models and then applied to model the temperature variation record decoded from the tree-ring widths of the Western Himalayas for the period spanning over 1226–2000 AD. For modeling the actual tree-ring temperature data, optimum network parameters are chosen appropriately and then cross-validation test is performed to ensure the generalization skill of the network on the new data set. Finally, prediction result based on the BNN model is compared with the conventional artificial neural network (ANN and the AR linear models results. The comparative results show that the BNN based analysis makes better prediction than the ANN and the AR models. The new BNN modeling approach provides a viable tool for climate studies and could also be exploited for modeling other kinds of environmental data.

  8. Late summer temperature reconstruction based on tree-ring density for Sygera Mountain, southeastern Tibetan Plateau

    Science.gov (United States)

    Li, Mingyong; Duan, Jianping; Wang, Lily; Zhu, Haifeng

    2018-04-01

    Although several tree-ring density-based summer/late summer temperature reconstructions have been developed on the Tibetan Plateau (TP), the understanding of the local/regional characteristics of summer temperature fluctuations on a long-term scale in some regions is still limited. To improve our understanding in these aspects, more local or regional summer temperature reconstructions extending back over several centuries are required. In this study, a new mean latewood density (LWD) chronology from Abies georgei var. smithii from the upper tree line of Sygera Mountain on the southeastern TP was developed to reconstruct the late summer temperature variability since 1820 CE. The bootstrapped correlation analysis showed that the LWD chronology index was significantly and positively correlated with the late summer (August-September) mean temperatures (r1950-2008 = 0.63, p < 0.001) recorded at the nearest meteorological station and that this reconstruction has considerable potential to represent the late summer temperature variability at the regional scale. Our late summer temperature reconstruction revealed three obvious cold periods (i.e., 1872-1908, 1913-1937 and 1941-1966) and two relatively warm phases (i.e., 1821-1871 and 1970-2008) over the past two centuries. Comparisons of our reconstruction with other independent tree-ring-based temperature reconstructions, glacier fluctuations and historical documental records from neighboring regions showed good agreement in these relatively cold and warm intervals. Our reconstruction exhibits an overall increasing temperature trend since the 1960s, providing new evidence supporting the recent warming of the TP. Moreover, our results also indicate that the late summer temperature variability of Sygera Mountain on the southeastern TP has potential links with the Pacific Decadal Oscillation (PDO).

  9. Environmental relevance of correlations of δ13C and climate in tree rings of young pines (Pinus silvestris L.)

    International Nuclear Information System (INIS)

    Hemmann, A.G.

    1993-08-01

    From two groups of trees, 15 damaged ones and 15 healthy ones, tree slices were taken and in these the tree-ring widths, ratios of δ 13 C isotopes in cellulose and trace element concentrations were determined. Healthy trees have wider tree-rings over their entire period of life from 1891 to 1986 than the group of trees of damage category 3 (severely damaged). The pattern of tree-ring width development, however, is similar. From eight synchronous δ 13 C traces of non-damaged pines a normal chronology was derived. The ontogenesis of some damaged individuals does not correspond to this normal course. In this way the onset of damage can be reconstructed by means of the δ 13 C values. A link between the δ 13 C values curves and anthropogenously induced changes of atmospheric CO 2 concentration could not be established. The yearly variations of the δ 13 C values of the normal chronology are climate-sensitive. The established trace element concentrations of the wood samples are neither in the toxic nor in the deficiency range. Their magnitude is abour equal in all radial sections, independently of the damage category. (UWA) [de

  10. Distribution of Mercury Concentrations in Tree Rings and Surface Soils Adjacent to a Phosphate Fertilizer Plant in Southern Korea.

    Science.gov (United States)

    Jung, Raae; Ahn, Young Sang

    2017-08-01

    This study aimed to determine mercury concentrations in tree rings and surface soils at distances of 4, 26 and 40 km from a fertilizer plant located in Yeosu City, Korea. Mercury concentrations in all tree rings were low prior to the establishment of the plant in 1977 and became elevated thereafter. The highest average mercury concentration in the tree rings was 11.96 ng g -1 at the Yeosu site located nearest to the plant, with the lowest average mercury concentration of 4.45 ng g -1 at the Suncheon site furthest away from the plant. In addition, the highest mercury content in the surface soil was 108.51 ng cm -3 at the Yeosu site, whereas the lowest mercury content in the surface soil was 31.47 ng cm -3 at the Suncheon site. The mercury levels decreased gradually with increasing distance from the plant.

  11. Oxygen isotopes in tree rings are a good proxy for Amazon precipitation and El Niño-Southern Oscillation variability

    Science.gov (United States)

    Brienen, Roel J. W.; Helle, Gerd; Pons, Thijs L.; Guyot, Jean-Loup; Gloor, Manuel

    2012-10-01

    We present a unique proxy for the reconstruction of variation in precipitation over the Amazon: oxygen isotope ratios in annual rings in tropical cedar (Cedrela odorata). A century-long record from northern Bolivia shows that tree rings preserve the signal of oxygen isotopes in precipitation during the wet season, with weaker influences of temperature and vapor pressure. Tree ring δ18O correlates strongly with δ18O in precipitation from distant stations in the center and west of the basin, and with Andean ice core δ18O showing that the signal is coherent over large areas. The signal correlates most strongly with basin-wide precipitation and Amazon river discharge. We attribute the strength of this (negative) correlation mainly to the cumulative rainout processes of oxygen isotopes (Rayleigh distillation) in air parcels during westward transport across the basin. We further find a clear signature of the El Niño-Southern Oscillation (ENSO) in the record, with strong ENSO influences over recent decades, but weaker influence from 1925 to 1975 indicating decadal scale variation in the controls on the hydrological cycle. The record exhibits a significant increase in δ18O over the 20th century consistent with increases in Andean δ18O ice core and lake records, which we tentatively attribute to increased water vapor transport into the basin. Taking these data together, our record reveals a fresh path to diagnose and improve our understanding of variation and trends of the hydrological cycle of the world's largest river catchment.

  12. Identification of Cherry green ring mottle virus on Sweet Cherry Trees in Korea

    Directory of Open Access Journals (Sweden)

    In-Sook Cho

    2013-12-01

    Full Text Available During the 2012 growing season, 154 leaf samples were collected from sweet cherry trees in Hwaseong, Pyeongtaek, Gyeongju, Kimcheon, Daegu, Yeongju and Eumseong and tested for the presence of Cherry green ring mottle virus (CGRMV. PCR products of the expected size (807 bp were obtained from 6 samples. The PCR products were cloned and sequenced. The nucleotide sequences of the clones showed over 88% identities to published coat protein sequences of CGRMV isolates in the GenBank database. The sequences of CGRMV isolates, CGR-KO 1−6 shared 98.8 to 99.8% nucleotide and 99.6 to 100% amino acid similarities. Phylogenetic analysis indicated that the Korean CGRMV isolates belong to the group II of CGRMV coat protein genes. The CGRMV infected sweet cherry trees were also tested for Apple chlorotic leaf spot virus (ACLSV, Apple mosaic virus (ApMV, Cherry necrotic rusty mottle virus (CNRMV, Cherry mottle leaf virus (CMLV, Cherry rasp leaf virus (CRLV, Cherry leafroll virus (CLRV, Cherry virus A (CVA, Little cherry virus 1 (LChV1, Prune dwarf virus (PDV and Prunus necrotic ringspot virus (PNRSV by RT-PCR. All of the tested trees were also infected with ACLSV.

  13. Landsat Time-series for the Masses: Predicting Wood Biomass Growth from Tree-rings Using Departures from Mean Phenology in Google Earth Engine

    Science.gov (United States)

    Foster, J. R.; D'Amato, A. W.; Itter, M.; Reinikainen, M.; Curzon, M.

    2017-12-01

    The terrestrial carbon cycle is perturbed when disturbances remove leaf biomass from the forest canopy during the growing season. Changes in foliar biomass arise from defoliation caused by insects, disease, drought, frost or human management. As ephemeral disturbances, these often go undetected and their significance to models that predict forest growth from climatic drivers remains unknown. Here, we seek to distinguish the roles of weather vs. canopy disturbance on forest growth by using dense Landsat time-series to quantify departures in mean phenology that in turn predict changes in leaf biomass. We estimated a foliar biomass index (FBMI) from 1984-2016, and predict plot-level wood growth over 28 years on 156 tree-ring monitoring plots in Minnesota, USA. We accessed the entire Landsat archive (sensors 4, 5 & 7) to compute FBMI using Google Earth Engine's cloud computing platform (GEE). GEE allows this pixel-level approach to be applied at any location; a feature we demonstrate with published wood-growth data from flux tower sites. Our Bayesian models predicted biomass changes from tree-ring plots as a function of Landsat FBMI and annual climate data. We expected model parameters to vary by tree functional groups defined by differences in xylem anatomy and leaf longevity, two traits with linkages to phenology, as reported in a recent review. We found that Landsat FBMI was a surprisingly strong predictor of aggregate wood-growth, explaining up to 80% of annual growth variation for some deciduous plots. Growth responses to canopy disturbance varied among tree functional groups, and the importance of some seasonal climate metrics diminished or changed sign when FBMI was included (e.g. fall and spring climatic water deficit), while others remained unchanged (current and lagged summer deficit). Insights emerging from these models can clear up sources of persistent uncertainty and open a new frontier for models of forest productivity.

  14. Extreme pointer years in tree-ring records of Central Spain as evidence of climatic events and the eruption of the Huaynaputina Volcano (Peru, 1600 AD)

    Science.gov (United States)

    Génova, M.

    2012-04-01

    The study of pointer years of numerous tree-ring chronologies of the central Iberian Peninsula (Sierra de Guadarrama) could provide complementary information about climate variability over the last 405 yr. In total, 64 pointer years have been identified: 30 negative (representing minimum growths) and 34 positive (representing maximum growths), the most significant of these being 1601, 1963 and 1996 for the negative ones, and 1734 and 1737 for the positive ones. Given that summer precipitation was found to be the most limiting factor for the growth of Pinus in the Sierra de Guadarrama in the second half of the 20th century, it is also an explanatory factor in almost 50% of the extreme growths. Furthermore, these pointer years and intervals are not evenly distributed throughout time. Both in the first half of the 17th and in the second half of 20th, they were more frequent and more extreme and these periods are the most notable for the frequency of negative pointer years in Central Spain. The interval 1600-1602 is of special significance, being one of the most unfavourable for tree growth in the centre of Spain, with 1601 representing the minimum index in the regional chronology. We infer that this special minimum annual increase was the effect of the eruption of Huaynaputina, which occurred in Peru at the beginning of 1600 AD. This is the first time that the effects of this eruption in the tree-ring records of Southern Europe have been demonstrated.

  15. Mediterranean drought fluctuation during the last 500 years based on tree-ring data

    Energy Technology Data Exchange (ETDEWEB)

    Nicault, A. [CEREGE, UMR 6635 CNRS/Universite Paul Cezanne, Aix-en-Provence (France); I.N.R.S., Centre ETE, Quebec, QC (Canada); Alleaume, S. [Cemagref, Aix en Provence (Germany); Brewer, S.; Guiot, J. [CEREGE, UMR 6635 CNRS/Universite Paul Cezanne, Aix-en-Provence (France); Carrer, M. [Universita degli Studi di Padova, Dipt. TeSAF - Treeline Ecology Research Unit - Agripolis, Legnaro (Italy); Nola, P. [Universita degli Studi di Pavia, Dipt. Ecologia del Territorio, Pavia (Italy)

    2008-08-15

    A 2.5 x 2.5 gridded summer (April-September) drought reconstruction over the larger Mediterranean land area (32.5 /47.5 N, 10 W/50 E; 152 grid points) is described, based on a network of 165 tree-ring series. The drought index used is the self-calibrated Palmer Drought Severity Index, and the period considered is 1500-2000. The reconstruction technique combines an analogue technique for the estimation of missing tree-ring data with an artificial neural network for optimal non-linear calibration, including a bootstrap error assessment. Tests were carried out on the various sources of error in the reconstructions. Errors related to the temporal variations of the number of proxies were tested by comparing four reconstructions calibrated with four different sized regressor datasets, representing the decrease in the number of available proxies over time. Errors related to the heterogeneous spatial density of predictors were tested using pseudo-proxies, provided by the global climate model ECHO-G. Finally the errors related to the imperfect climate signal recorded by tree-ring series were tested by adding white noise to the pseudo-proxies. Reconstructions pass standard cross-validation tests. Nevertheless tests using pseudo-proxies show that the reconstructions are less good in areas where proxies are rare, but that the average reconstruction curve is robust. Finally, the noise added to proxies, which is by definition a high frequency component, has a major effect on the low frequency signal, but not on the medium frequencies. The comparison of the low frequency trends of our mean reconstruction and the GCM simulation indicates that the detrending method used is able to preserve the long-term variations of reconstructed PDSI. The results also highlight similar multi-decadal PDSI variations in the central and western parts of the Mediterranean basin and less clear low frequency changes in the east. The sixteenth and the first part of the seventeenth centuries are

  16. 348-YEAR PRECIPITATION RECONSTRUCTION FROM TREE-RINGS FOR THE NORTH SLOPE OF THE MIDDLE TIANSHAN MOUNTAINS

    Institute of Scientific and Technical Information of China (English)

    袁玉江; 李江风; 张家宝

    2001-01-01

    Correlation census shows that the correlation between the tree-ring chronologies in the Urumqi River Basin and precipitation during July in the last year to February in the concurrent year is significant, and the best single correlation coefficient is 0.74, with significance level of 0. 0001.Using two residual chronologies collected from west Baiyanggou and Boerqingou, precipitation for 348 years can be reconstructed in the North Slope of middle Tianshan Mountains, its explained variance is 62%. According to much verification from independent precipitation data, historical climate records, glacier and other data, it shows that the reconstructed precipitation series of 348 years is reliable. Analysis of precipitation features indicates that there were three wet periods occurring during 1671 (?) -1692, 1716-1794 and 1825-1866 and three dry periods during 1693 - 1715, 1795- 1824 and 1867- 1969. Two wet periods, during 1716- 1794 and 1825 - 1866,correspond to the times of the second and the third glacial terminal moraine formation, which is in front of No. 1 glacier in Urumqi River source. According to computation, corresponding annual precipitation amounts are 59 mm and 30 mm more than now. The reconstructed precipitation series has a significant drying trend from 1716 to 1969, and has better representativeness to the precipitation of Urumqi and Changji Prefecture on the North Slope of Tianshan Mountains.

  17. Sensitivity of tree ring growth to local and large-scale climate variability in a region of Southeastern Brazil

    Science.gov (United States)

    Venegas-González, Alejandro; Chagas, Matheus Peres; Anholetto Júnior, Claudio Roberto; Alvares, Clayton Alcarde; Roig, Fidel Alejandro; Tomazello Filho, Mario

    2016-01-01

    We explored the relationship between tree growth in two tropical species and local and large-scale climate variability in Southeastern Brazil. Tree ring width chronologies of Tectona grandis (teak) and Pinus caribaea (Caribbean pine) trees were compared with local (Water Requirement Satisfaction Index—WRSI, Standardized Precipitation Index—SPI, and Palmer Drought Severity Index—PDSI) and large-scale climate indices that analyze the equatorial pacific sea surface temperature (Trans-Niño Index-TNI and Niño-3.4-N3.4) and atmospheric circulation variations in the Southern Hemisphere (Antarctic Oscillation-AAO). Teak trees showed positive correlation with three indices in the current summer and fall. A significant correlation between WRSI index and Caribbean pine was observed in the dry season preceding tree ring formation. The influence of large-scale climate patterns was observed only for TNI and AAO, where there was a radial growth reduction in months preceding the growing season with positive values of the TNI in teak trees and radial growth increase (decrease) during December (March) to February (May) of the previous (current) growing season with positive phase of the AAO in teak (Caribbean pine) trees. The development of a new dendroclimatological study in Southeastern Brazil sheds light to local and large-scale climate influence on tree growth in recent decades, contributing in future climate change studies.

  18. A technique to identify annual growth rings in Eucalyptus grandis using annual measurements of diameter at breast height and gamma ray densitometry

    CSIR Research Space (South Africa)

    Naidoo, Sasha

    2010-06-01

    Full Text Available A technique was developed to identify annual growth rings in E. grandis using a combination of annual measurements of diameter at breast height (DBH) from permanent sample plot (PSP) datasets and bark-pith density profiles. By assessing the pattern...

  19. [Dendroclimatic potentials for the tree rings of Huangshan pine (Pinus taiwanensis ) at Xiaolinhai in the western Dabie Mountains, China].

    Science.gov (United States)

    Peng, Jian-Feng; Li, Guo-Dong; Li, Ling-Ling

    2014-07-01

    By using the dendrochronology research methods, this paper developed the 1915-2011 tree ring-width standard chronology of the Huangshan pine (Pinus taiwanesis) at the north slope of western Dabie Mountains in the junction of Hubei, Henan and Anhui provinces. High mean sensitivity (MS) indicated that there was conspicuous high-frequency climate signals and high first-order autocorrelation (AC) showed there were significant lag-effects of tree previous growth. The higher signal-to-noise ratio (SNR) and expressed population signal (EPS) indicated that the trees had high levels of common climate signals. Correlations between the tree ring-width standard chronology and climatic factors (1959-2011) revealed the significant influences of temperature, precipitation and relative humidity on the tree width growth of Huangshan pine by the end of growing season (September and October). Significant positive correlations were found between the tree-ring indices and the Palmer drought severity index (PDSI) of current September and October. In conclusion, the combination of water and heat of September and October is the major effect factor for the growth of Huangshan pine in western Dabie Mountains.

  20. Tree-ring based reconstruction of rockfalls at Cofre de Perote volcano, Mexico

    Science.gov (United States)

    Franco-Ramos, Osvaldo; Stoffel, Markus; Vázquez-Selem, Lorenzo

    2017-08-01

    In this study, dendrogeomorphic techniques are employed to analyse the temporal frequency and spatial distribution of rockfalls on a talus slope of La Teta valley, located on the NW slopes of Cofre de Perote volcano at 4000 m above sea level. Based on the interpretation of disturbance signals in growth rings of old-growth Pinus hartwegii Lindl. trees, we identify 100 growth disturbances related with rockfall events dated between 1780 and 2011, with slightly more than half of these events being dated to the last 50 years. The sectors most susceptible to rockfall correspond with the young rock lobes located at the foot of scarps. Roughly three in ten events has been triggered by regional, M > 6 earthquakes, whereas half of the events activity coincides with periods characterized by severe, prolonged summer rainfalls such as the ones occurred in 1995, 1998, 2005 and 2011.

  1. Secular variation of cosmic ray intensity recorded in the radiocarbon concentration of tree rings

    International Nuclear Information System (INIS)

    Kigoshi, K.

    1978-01-01

    Study of the secular variations of cosmic ray intensity on the basis of the secular variations of atmospheric radiocarbon concentration in 8000 years is considered. The data on the radiocarbon concentration is received by three laboratories using the dendrochronologically dated tree ring samples. In order to use the data the variations due to geochemical process must be eliminated. From this point of view the climatic effect on the atmospheric radiocarbon concenttration is estimated using the data on sunspot number and global surface temperature during 1650-1800 y. The barge influence of climate on the atmospheric radiocarbon concentration syggests the small contribution of change of radiocarbon production rate to the short-period fluctuations in the atmospheric radiocarbon concentration. Elimination of variations caused by climate and sunspot activities from the variations in atmospheric radiocarbon concentration gives a long-term scale of its concentration which agrees well to the observed paleo-geomagnetic data

  2. Tree ring and ice core time scales around the Santorini eruption

    Science.gov (United States)

    Löfroth, Elin; Muscheler, Raimund; Aldahan, Ala; Possnert, Göran; Berggren, Ann-Marie

    2010-05-01

    When studying cosmogenic radionuclides in ice core and tree ring archives around the Santorini eruption a ~20 year discrepancy was found between the records (Muscheler 2009). In this study a new 10Be dataset from the NGRIP ice core is presented. It has a resolution of 7 years and spans the period 3752-3244 BP (1803-1295 BC). The NGRIP 10Be record and the previously published 10Be GRIP record were compared to the IntCal datasets to further investigate the discrepancy between the ice core and tree ring chronologies. By modelling the 14C production rate based on atmospheric 14C records a comparison could be made to the 10Be flux which is assumed to represent the 10Be production rate. This showed a time shift of ~23 years between the records. The sensitivity of the results to changes in important model parameters was evaluated. Uncertainties in the carbon cycle model cannot explain a substantial part of the timing differences. Potential influences of climate and atmospheric processes on the 10Be deposition were studied using δ18O from the respective cores and GISP2 ice core ion data. The comparison to δ18O revealed a small but significant correlation between 10Be flux and δ18O when the 14C-derived production signal was removed from the 10Be curves. The ion data, as proxies for atmospheric circulation changes, did not show any correlations to the 10Be record or the 10Be/14C difference. When including possible data uncertainties there is still a minimum discrepancy of ~10 years between the 10Be ice core and the 14C tree ring record. Due to lack of alternative explanations it is concluded that the ice core and/or the tree ring chronologies contains unaccounted errors in this range. This also reconciles the radiocarbon 1627-1600 BC (Friedrich et al., 2006) and ice core 1642±5 BC (Vinther et al., 2006) datings of the Santorini eruption. Friedrich, W.L., Kromer, B., Friedrich, M., Heinemeier, J., Pfeiffer, T., & Talamo, S., 2006: Santorini eruption radiocarbon dated to

  3. Central Vietnam climate over the past five centuries from cypress tree rings

    Science.gov (United States)

    Buckley, Brendan M.; Stahle, Daniel K.; Luu, Hong Truong; Wang, S.-Y. Simon; Nguyen, Tran Quoc Trung; Thomas, Philip; Le, Canh Nam; Ton, That Minh; Bui, The Hoang; Nguyen, Van Thiet

    2017-06-01

    We present the first crossdated tree ring record from central Vietnam, derived from the growth rings of the rare cypress Fokienia hodginsii from the mountains of Quang Nam Province near the Laos border. The Quang Nam Fokienia hodginsii time series (QNFH), based on the crossdated sequences of 71 increment core samples from 37 mature trees, is the third published dendrochronological record from this species. The record extends 667 years from AD 1347 to 2013 and exhibits a mean series intercorrelation of 0.526, similarly significant with the first two published Fokienia hodginsii records: 0.474 for Mu Cang Chai (MCFH) and 0.578 for Bidoup-Nui Ba National Park (BDFH) in the north and south of Vietnam, respectively. The Expressed Population Signal (EPS) for the QNFH record exceeds the generally accepted threshold of 0.85 back to AD 1567, but remains above 0.8 back to 1550. Similar to the MCFH and BDFH records, QNFH expresses statistically significant linkages to regional hydroclimate metrics and the El Niño-Southern Oscillation. Here we present a reconstruction of the Standardized Precipitation Evapotranspiration Index for the month of April, averaged over a large region of Southeast Asia. As with prior studies we demonstrate that cool phase (La Niña) and warm phase (El Niño) events are linked to regional wet and dry conditions, respectively, with linkages to modulation of the surface water temperature over the adjacent sea to the east of Vietnam as well as the Indian Ocean. A late eighteenth century megadrought that is expressed widely across South and Southeast Asia, and notably from the MCFH and BDFH records described above, is not as pronounced in Central Vietnam and we explore the reasons why.

  4. Bayesian Models for Streamflow and River Network Reconstruction using Tree Rings

    Science.gov (United States)

    Ravindranath, A.; Devineni, N.

    2016-12-01

    Water systems face non-stationary, dynamically shifting risks due to shifting societal conditions and systematic long-term variations in climate manifesting as quasi-periodic behavior on multi-decadal time scales. Water systems are thus vulnerable to long periods of wet or dry hydroclimatic conditions. Streamflow is a major component of water systems and a primary means by which water is transported to serve ecosystems' and human needs. Thus, our concern is in understanding streamflow variability. Climate variability and impacts on water resources are crucial factors affecting streamflow, and multi-scale variability increases risk to water sustainability and systems. Dam operations are necessary for collecting water brought by streamflow while maintaining downstream ecological health. Rules governing dam operations are based on streamflow records that are woefully short compared to periods of systematic variation present in the climatic factors driving streamflow variability and non-stationarity. We use hierarchical Bayesian regression methods in order to reconstruct paleo-streamflow records for dams within a basin using paleoclimate proxies (e.g. tree rings) to guide the reconstructions. The riverine flow network for the entire basin is subsequently modeled hierarchically using feeder stream and tributary flows. This is a starting point in analyzing streamflow variability and risks to water systems, and developing a scientifically-informed dynamic risk management framework for formulating dam operations and water policies to best hedge such risks. We will apply this work to the Missouri and Delaware River Basins (DRB). Preliminary results of streamflow reconstructions for eight dams in the upper DRB using standard Gaussian regression with regional tree ring chronologies give streamflow records that now span two to two and a half centuries, and modestly smoothed versions of these reconstructed flows indicate physically-justifiable trends in the time series.

  5. Tree-ring based reconstruction of the seasonal timing, major events and origin of rockfall on a case-study slope in the Swiss Alps

    Directory of Open Access Journals (Sweden)

    D. M. Schneuwly

    2008-03-01

    Full Text Available Tree-ring analysis has been used to reconstruct 22 years of rockfall behavior on an active rockfall slope near Saas Balen (Swiss Alps. We analyzed 32 severely injured trees (L. decidua, P. abies and P. cembra and investigated cross-sections of 154 wounds.

    The intra-annual position of callus tissue and of tangential rows of traumatic resin ducts was determined in order to reconstruct the seasonality of past rockfall events. Results indicate strong intra- and inter-annual variations of rockfall activity, with a peak (76% observed in the dormant season (early October – end of May. Within the growth season, rockfall regularly occurs between the end of May and mid July (21.4%, whereas events later in the season appear to be quite rare (2.6%. Findings suggest that rockfall activity at the study site is driven by annual thawing processes and the circulation of melt water in preexisting fissures. Data also indicate that 43% of all rockfall events occurred in 1995, when two major precipitation events are recorded in nearby meteorological stations. Finally, data on impact angles are in very good agreement with the geomorphic situation in the field.

  6. Temperature variability over the past millennium inferred from Northwestern Alaska tree rings

    Energy Technology Data Exchange (ETDEWEB)

    D' Arrigo, Rosanne; Mashig, Erika; Jacoby, Gordon [Lamont-Doherty Earth Observatory, Tree-Ring Laboratory, Palisades, NY (United States); Frank, David [WSL, Birmensdorf (Switzerland); Wilson, Rob [University of Edinburgh, School of Geosciences, Grant Institute, Edinburgh (United Kingdom)

    2005-02-01

    We describe a new tree-ring width data set of 14 white spruce chronologies for the Seward Peninsula (SP), Alaska, based on living and subfossil wood dating from 1358 to 2001 AD. A composite chronology derived from these data correlates positively and significantly with summer temperatures at Nome from 1910 to 1970, after which there is some loss of positive temperature response. There is inferred cooling during periods within the Little Ice Age (LIA) from the early to middle 1600s and late 1700s to middle 1800s; and warming from the middle 1600s to early 1700s. We also present a larger composite data set covering 978-2001 AD, utilizing the SP ring-width data in combination with archaeological wood measurements and other recent collections from northwestern Alaska. The Regional Curve Standardization (RCS) method was employed to maximize potential low-frequency information in this data set. The RCS chronology shows intervals of persistent above-average growth around the time of the Medieval Warm Period (MWP) early in the millennium, which are comparable to growth levels in recent centuries. There is a more sustained cold interval during the LIA inferred from the RCS record as compared to the SP ring-width series. The chronologies correlate significantly with Bering and Chukchi Sea sea surface temperatures and with the Pacific Decadal Oscillation index. These atmosphere-ocean linkages probably account for the differences between these records and large-scale reconstructions of Arctic and Northern Hemisphere temperatures based largely on continental interior proxy data. (orig.)

  7. Growth tree rings as bioindicator of environmental pollution employing SR-TXRF

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Bruna Fernanda; Moreira, Silvana [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: silvana@fec.unicamp.br; Vives, Ana Elisa Sirito de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil)]. E-mail: aesvives@unimep.br; Medeiros, Jean Gabriel da Silva; Tomazello Filho, Mario [Universidade de Sao Paulo (USP), SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz]. E-mail: jeangm@esalq.usp.br; Zucchi, Orgheda Luiza Araujo Domingues [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: olzucchi@fcfrp.usp.br

    2007-07-01

    The present work has the aim to evaluate the use of tree ring as a bioindicator of the environmental pollution in urban and industrial areas. The sampling was made in a area located at the Forest Park, in the Bauru city, Sao Paulo state/Brazil. The area was contaminated by battery industries residues, which was interdicted by the Environmental Control Agency of the Sao Paulo State (CETESB), on March, 2002. Trees of Copaifera langsdorffi L. species were sampling in two different sites. The first one is near to the industry and other site 1700 m far. Synchrotron Radiation Total Reflection X-Ray Fluorescence technique (SR-TXRF) was employed to identify and quantify the metals of toxicological importance in the wood samples. The analysis was performed in the Brazilian Synchrotron Light Laboratory using a white beam for excitation and a hyperpure germanium detector for X-ray detection. In wood samples Cr, Co, Ni, Cu, Zn, As and Pb were determined. (author)

  8. Growth tree rings as bioindicator of environmental pollution employing SR-TXRF

    International Nuclear Information System (INIS)

    Faria, Bruna Fernanda; Moreira, Silvana; Medeiros, Jean Gabriel da Silva; Tomazello Filho, Mario; Zucchi, Orgheda Luiza Araujo Domingues

    2007-01-01

    The present work has the aim to evaluate the use of tree ring as a bioindicator of the environmental pollution in urban and industrial areas. The sampling was made in a area located at the Forest Park, in the Bauru city, Sao Paulo state/Brazil. The area was contaminated by battery industries residues, which was interdicted by the Environmental Control Agency of the Sao Paulo State (CETESB), on March, 2002. Trees of Copaifera langsdorffi L. species were sampling in two different sites. The first one is near to the industry and other site 1700 m far. Synchrotron Radiation Total Reflection X-Ray Fluorescence technique (SR-TXRF) was employed to identify and quantify the metals of toxicological importance in the wood samples. The analysis was performed in the Brazilian Synchrotron Light Laboratory using a white beam for excitation and a hyperpure germanium detector for X-ray detection. In wood samples Cr, Co, Ni, Cu, Zn, As and Pb were determined. (author)

  9. AMS measurement of C-14 concentration in a single-year ring of a 2500-yr-old tree

    International Nuclear Information System (INIS)

    Sakurai, H.; Gandou, T.; Kato, W.; Sawaki, Y.; Matsumoto, T.; Aoki, T.; Matsuzaki, H.; Gunji, S.; Tokanai, F.

    2004-01-01

    The 14 C concentration in rings of an old tree that date back approximately 2500 yr has been measured at single-year intervals with a highly accurate liquid scintillation counter (LSC) (0.2%) to investigate the 11-yr periodicity of solar activity. To investigate the applicability of AMS to accurate 14 C measurement, 16 graphite samples produced from the cellulose of a single-year tree ring of a 2500-yr-old cedar were measured with the micro analysis laboratory tandem (MALT) accelerator, at The University of Tokyo, and the results were compared with the 14 C age determined using LSC. The average 14 C age of the single-year tree ring calculated from 16 measurements was 2496 ± 23 yr BP, corresponding to the statistical accuracy of 0.26%. This was consistent with the age of 2514 ± 23 yr BP determined using LSC within the acceptable error range, which indicates that accelerator mass spectrometry (AMS) is applicable for accurate 14 C measurement using multi-graphite for the same single-year tree ring

  10. Flood-ring formation and root development in response to experimental flooding of young Quercus robur trees

    NARCIS (Netherlands)

    Copini, Paul; Ouden, den Jan; Robert, Elisabeth M.R.; Tardif, Jacques C.; Loesberg, Walter A.; Goudzwaard, Leo; Sass-Klaassen, Ute

    2016-01-01

    Spring flooding in riparian forests can cause significant reductions in earlywood-vessel size in submerged stem parts of ring-porous tree species, leading to the presence of ‘flood rings’ that can be used as a proxy to reconstruct past flooding events, potentially over millennia. The mechanism of

  11. New tree-ring evidence for the Late Glacial period from the northern pre-Alps in eastern Switzerland

    Czech Academy of Sciences Publication Activity Database

    Reinig, F.; Nievergelt, D.; Esper, J.; Friedrich, M.; Helle, G.; Hellmann, L.; Kromer, B.; Morganti, S.; Pauly, M.; Sookdeo, A.; Tegel, W.; Treydte, K.; Verstege, A.; Wacker, L.; Büntgen, Ulf

    2018-01-01

    Roč. 186, APR (2018), s. 215-224 ISSN 0277-3791 Keywords : new-zealand kauri * laacher see volcano * ice-core records * radiocarbon calibration * central-europe * cal bp * southern-hemisphere * last deglaciation * hohenheim oak * climate * Central Europe * Dendrochronology * Late Glacial * Paleoclimatology * Radiocarbon * Subfossil wood * Switzerland * Tree rings * Younger Dryas Impact factor: 4.797, year: 2016

  12. TREE-RING INDICES AND ISOTOPE SIGNATURES OF PINUS PONDEROSA RELATED TO HISTORIC OZONE CHANGES OUTSIDE LOS ANGELES

    Science.gov (United States)

    Ozone concentrations in the Los Angeles (LA) basin were at historic highs in the late 1970s. Since that time Clean Air regulations have helped lower ozone, but little is known of the long-term vegetation responses. Extensive research has used tree-ring indices together with the...

  13. Measurement of {sup 14}C time scale of the rings of a tree by accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Hirotaka; Furukawa, Michiaki [Nagoya Univ. (Japan). School of Science; Yonenobu, Hitoshi; Ikeda, Akiko; Nakamura, Toshio

    1996-12-01

    {sup 14}C time scale is different from a histrical data in order that it is calculated by assuming that the concentration of {sup 14}C in the sample has not been changed by age. The object of this work is to make clear the errors in measurement of {sup 14}C time scale of the ring of a tree known the tree age. The every year ring of a Hinoki in Kiso, 950 years old, was used as a sample. The most external ring is determined as 1923 years old on the basis of the dendrochronology. The rings after 1120 years were used as the samples. {alpha}-cellulose, the most stable component in the structural components of cell of tree, was prepared from each ring. About 8 mg of {alpha}-cellulose was reduced to graphite to be measured by the tandem thoron analytic meter. The results obtained showed that {sup 14}C time scale was older than that of the histrical data in the twelfth and thirteenth century, but it was more new than that of the histrical data from the late seventeenth to the middle of eighteenth century. The results were agreement with that of Stuiver and Pearson (1933). (S.Y.)

  14. Modelling tree ring cellulose δ18O variations in two temperature-sensitive tree species from North and South America

    Directory of Open Access Journals (Sweden)

    A. Lavergne

    2017-11-01

    Full Text Available Oxygen isotopes in tree rings (δ18OTR are widely used to reconstruct past climates. However, the complexity of climatic and biological processes controlling isotopic fractionation is not yet fully understood. Here, we use the MAIDENiso model to decipher the variability in δ18OTR of two temperature-sensitive species of relevant palaeoclimatological interest (Picea mariana and Nothofagus pumilio and growing at cold high latitudes in North and South America. In this first modelling study on δ18OTR values in both northeastern Canada (53.86° N and western Argentina (41.10° S, we specifically aim at (1 evaluating the predictive skill of MAIDENiso to simulate δ18OTR values, (2 identifying the physical processes controlling δ18OTR by mechanistic modelling and (3 defining the origin of the temperature signal recorded in the two species. Although the linear regression models used here to predict daily δ18O of precipitation (δ18OP may need to be improved in the future, the resulting daily δ18OP values adequately reproduce observed (from weather stations and simulated (by global circulation model δ18OP series. The δ18OTR values of the two species are correctly simulated using the δ18OP estimation as MAIDENiso input, although some offset in mean δ18OTR levels is observed for the South American site. For both species, the variability in δ18OTR series is primarily linked to the effect of temperature on isotopic enrichment of the leaf water. We show that MAIDENiso is a powerful tool for investigating isotopic fractionation processes but that the lack of a denser isotope-enabled monitoring network recording oxygen fractionation in the soil–vegetation–atmosphere compartments limits our capacity to decipher the processes at play. This study proves that the eco-physiological modelling of δ18OTR values is necessary to interpret the recorded climate signal more reliably.

  15. Trends of 13C/12C ratios in pinyon tree rings of the American Southwest and the global carbon cycle

    International Nuclear Information System (INIS)

    Leavitt, S.W.; Long, A.

    1986-01-01

    An accurate atmospheric 13 C/ 12 C chronology can provide important constraints to models of the global carbon cycle. Trees accumulate carbon from atmospheric CO 2 into growth rings and offer potential for 13 C/ 12 C reconstructions, but results have not been reproducible. This paper presents δ 13 C curves from 5 sites, representing 20 pinyon (Pinus edulis) trees, where cores of 4 trees from each site have been pooled into a composite sample. Isotopic analysis of cellulose in 5-yr ring groups produces curves with a general trend of decreasing δ 13 C after 1800, but with pronounced short-term fluctuations superimposed upon the trend. Evidence indicates the fluctuations are strongly related to moisture availability (drought). A mean curve of the 5 δ 13 C chronologies from which the fossil-fuel component is subtracted suggests a substantial biospheric CO 2 contribution to the atmosphere since 1800

  16. Quantitative Reconstruction of Sulfur Deposition Using a Mixing Model Based on Sulfur Isotope Ratios in Tree Rings.

    Science.gov (United States)

    Ishida, Takuya; Tayasu, Ichiro; Takenaka, Chisato

    2015-11-01

    Quantification of sulfur (S) deposition is critical to deciphering the environmental archive of S in terrestrial ecosystems. Here we propose a mixing model that quantifies S deposition based on the S isotope ratio (δS) in tree rings. We collected samples from Japanese cedar ( D. Don) stumps from two sites: one near Yokkaichi City (YOK), which is well known for having the heaviest S air pollution in the world, and one at Inabu-cho (INA) in central Japan, which has been much less affected by air pollution. The δS profiles at both sites are consistent with S air pollution and contributions of anthropogenic S. The minimum value in YOK is lower than the δS values of anthropogenic S or any other possible source. Because the δS in the tree rings is affected by fractionation in the forest ecosystems, we used a mixing model to account for the isotope effects and to distinguish the sources of S. Based on the model results, we infer that the peak of S emissions at YOK occurred sometime between the late 1960s and early 1970s (489 mmol m yr). This estimated value is comparable with the highest reported values in Europe. This is the first quantitative estimate of anthropogenic input of S in forest systems based on δS in tree rings. Our results suggest that tree ring data can be used when monitoring stations of atmospheric S are lacking and that estimates of S deposition using δS in tree rings will advance our understanding of the local-scale S dynamics and the effect of human activities on it. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  17. AMS 14C measurements for tree-ring samples from Japanese woods from 4c AD to 8c AD

    International Nuclear Information System (INIS)

    Ozaki, Hiromasa; Sakamoto, Minoru; Imamura, Mineo; Mitsutani, Takumi

    2010-01-01

    Regional offsets of atmospheric 14 C concentration, as represented by differences from IntCal calibration datasets, are discussed at times in relation to universal use of international radiocarbon calibration curve. In the construction of IntCal, 14 C contents of contemporaneous tree-ring samples from different regions in the northern hemisphere have been used, because the regional differences were indistinguishable from errors of measurements. Nowadays, high-precision 14 C results can be obtained much more easily than before, so more attention should be paid to the possible regional offsets. Most parts of IntCal has been constructed by using 14 C contents of tree-ring samples from woods in high latitude of Europe and North America, which are farthest from Japan in the northern hemisphere. So far, we have measured 14 C contents of tree-ring samples from Japanese wood samples dendrochronologically dated from 11th century BC to 4th century AD in order to investigate regional offset in Japan. Although the obtained results agreed well with IntCal in general, there were some periods when the 14 C contents differ significantly from IntCal. In this paper, we report the new results of AMS 14 C measurement for Japanese tree-ring samples ranging from 4th century AD to 8th century AD. The results show a significant disagreement with IntCal at around 630 AD. Similar difference was indicated by 14 C contents of tree-ring samples from other Japanese woods (Imamura et al., 2007). So it is certain that the regional offset in Japan exists at around 630 AD. (author)

  18. Imprints of climate signals in a 204 year 18O tree-ring record of Nothofagus pumilio from Perito Moreno Glacier, southern Patagonia (50°S).

    Science.gov (United States)

    Grießinger, Jussi; Langhamer, Lukas; Schneider, Christoph; Saß, Björn-Lukas; Steger, David; Skvarca, Pedro; Braun, Matthias H.; Meier, Wolfgang J.-H.; Srur, Ana M.; Hochreuther, Philipp

    2018-04-01

    A 204 year-long record of 18O in tree-ring cellulose of southern beech (Nothofagus pumilio) from a site near Perito Moreno Glacier (50°S) in southern Patagonia was established to assess its potential for a climate reconstruction. The annually resolved oxygen isotope chronology is built out of seven individual tree-ring 18O series with a significant mean inter-series correlation (r = 0.61) and is the first of its kind located in Southern America south of 50°S. Over a common period from 1960 to 2013 of available stationary and high-resolution gridded CRU TS v. 4.01 data, the 18O chronology exhibits a strong sensitivity towards hydroclimatic as well as temperature parameters as revealed by correlation analyses. Among these, positive correlations with maximum temperature in the first part of the summer season (CRU rONDJ = 0.51, pAmerica. The modulation of positive and negative anomalies within this series can be interlinked to changes in moisture source origin as revealed by backward trajectory modeling. Additionally, these anomalies can be directly associated to positive or negative phases of the Antarctic Oscillation Index (AAOI) and therefore the strength of the Westerlies. Aligned by the analysis on the influence of different main weather types on the 18O chronology it is shown that such time-series hold the potential to additionally capture their respective influence and change during the last centuries.

  19. Above-ground woody carbon sequestration measured from tree rings is coherent with net ecosystem productivity at five eddy-covariance sites.

    Science.gov (United States)

    Babst, Flurin; Bouriaud, Olivier; Papale, Dario; Gielen, Bert; Janssens, Ivan A; Nikinmaa, Eero; Ibrom, Andreas; Wu, Jian; Bernhofer, Christian; Köstner, Barbara; Grünwald, Thomas; Seufert, Günther; Ciais, Philippe; Frank, David

    2014-03-01

    • Attempts to combine biometric and eddy-covariance (EC) quantifications of carbon allocation to different storage pools in forests have been inconsistent and variably successful in the past. • We assessed above-ground biomass changes at five long-term EC forest stations based on tree-ring width and wood density measurements, together with multiple allometric models. Measurements were validated with site-specific biomass estimates and compared with the sum of monthly CO₂ fluxes between 1997 and 2009. • Biometric measurements and seasonal net ecosystem productivity (NEP) proved largely compatible and suggested that carbon sequestered between January and July is mainly used for volume increase, whereas that taken up between August and September supports a combination of cell wall thickening and storage. The inter-annual variability in above-ground woody carbon uptake was significantly linked with wood production at the sites, ranging between 110 and 370 g C m(-2) yr(-1) , thereby accounting for 10-25% of gross primary productivity (GPP), 15-32% of terrestrial ecosystem respiration (TER) and 25-80% of NEP. • The observed seasonal partitioning of carbon used to support different wood formation processes refines our knowledge on the dynamics and magnitude of carbon allocation in forests across the major European climatic zones. It may thus contribute, for example, to improved vegetation model parameterization and provides an enhanced framework to link tree-ring parameters with EC measurements. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  20. Ozone air pollution effects on tree-ring growth,{delta}{sup 13}C, visible foliar injury and leaf gas exchange in three ozone-sensitive woody plant species

    Energy Technology Data Exchange (ETDEWEB)

    Novak, K. [Swiss Federal Inst. for Forest, Snow and Landscape Research, Birmensdorf (Switzerland); Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Zurich (Switzerland); Saurer, M. [Paul Scherrer Inst. Villigen (Switzerland); Fuhrer, J. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Zurich (Switzerland); Skelly, J.M. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Plant Pathology; Krauchi, N.; Schaub, M. [Swiss Federal Inst. for Forest, Snow and Landscape Research, Birmensdorf (Switzerland)

    2007-07-15

    Species specific plant responses to tropospheric ozone pollution depend on a range of morphological, biochemical and physiological characteristics as well as environmental factors. The effects of ambient tropospheric ozone on annual tree-ring growth, {delta}{sup 13} C in the rings, leaf gas exchange and ozone-induced visible foliar injury in three ozone-sensitive woody plant species in southern Switzerland were assessed during the 2001 and 2002 growing seasons. Seedlings of Populus nigra L., Viburnum lantana L. and Fraxinus excelsior L. were exposed to charcoal-filtered air and non-filtered air in open-top chambers, and to ambient air (AA) in open plots. The objective was to determine if a relationship exists between measurable ozone-induced effects at the leaf level and subsequent changes in annual tree-ring growth and {delta} {sup 13} C signatures. The visible foliar injury, early leaf senescence and premature leaf loss in all species was attributed to the ambient ozone exposures in the region. Ozone had pronounced negative effects on net photosynthesis and stomatal conductance in all species in 2002 and in V. lantana and F. excelsior in 2001. Water-use efficiency decreased and intercellular carbon dioxide concentrations increased in all species in response to ozone in 2002 only. The width and {delta}{sup 13} C of the 2001 and 2002 growth rings were measured for all species at the end of the 2002 growing season. Significant ozone-induced effects at the leaf level did not correspond to reduced tree-ring growth or increased {delta}{sup 13} C in all species, suggesting that the timing of ozone exposure and extent of leaf-level responses may be relevant in determining the sensitivity of tree productivity to ozone exposure. 48 refs., 4 tabs., 2 figs.

  1. Forest Growth Responses to Drought at Short- and Long-Term Scales in Spain: Squeezing the Stress Memory from Tree Rings

    Directory of Open Access Journals (Sweden)

    J. Julio Camarero

    2018-02-01

    Full Text Available Drought-triggered declines in forest productivity and associated die-off events have increased considerably due to climate warming in the last decades. There is an increasing interest in quantifying the resilience capacity of forests against climate warming and drought to uncover how different stands and tree species will resist and recover after more frequent and intense droughts. Trees form annual growth rings that represent an accurate record of how forest growth responded to past droughts. Here we use dendrochronology to quantify the radial growth of different forests subjected to contrasting climatic conditions in Spain during the last half century. Particularly, we considered four climatically contrasting areas where dominant forests showed clear signs of drought-induced dieback. Studied forests included wet sites dominated by silver fir (Abies alba in the Pyrenees and beech (Fagus sylvatica stands in northern Spain, and drought-prone sites dominated by Scots pine (Pinus sylvestris in eastern Spain and black pine (Pinus nigra in the semi-arid south-eastern Spain. We quantified the growth reduction caused by different droughts and assessed the short-and long-term resilience capacity of declining vs. non-declining trees in each forest. In all cases, drought induced a marked growth reduction regardless tree vigor. However, the capacity to recover after drought (resilience at short- and long-term scales varied greatly between declining and non-declining individuals. In the case of beech and silver fir, non-declining individuals presented greater growth rates and capacity to recover after drought than declining individuals. For Scots pine, the resilience to drought was found to be lower in recent years regardless the tree vigor, but the growth reduction caused by successive droughts was more pronounced in declining than in non-declining individuals. In the black pine forest an extreme drought induced a marked growth reduction in declining

  2. Preliminary evaluation of the potential of tree-ring cellulose content as a novel supplementary proxy in dendroclimatology

    Science.gov (United States)

    Ziehmer, Malin M.; Nicolussi, Kurt; Schlüchter, Christian; Leuenberger, Markus

    2018-02-01

    Cellulose content (CC (%)) in tree rings is usually utilised as a tool to control the quality of the α-cellulose extraction from tree rings in the preparation of stable-isotope analysis in wooden tissues. Reported amounts of CC (%) are often limited to mean values per tree. For the first time, CC (%) series from two high-Alpine species, Larix decidua Mill. (European Larch, LADE) and Pinus cembra L. (Swiss stone pine, PICE) are investigated in modern wood samples and Holocene wood remains from the Early and mid-Holocene. Modern CC (%) series reveal a species-specific low-frequency trend independent of their sampling site over the past 150 years. Climate-cellulose relationships illustrate the ability of CC (%) to record temperature in both species but for slightly different periods within the growing season. The Holocene CC (%) series illustrate diverging low-frequency trends in both species, independent of sampling site characteristics (latitude, longitude and elevation). Moreover, potential age trends are not apparent in the two coniferous species. The arithmetic mean of CC (%) series in the Early and mid-Holocene indicate low CC (%) succeeding cold events. In conclusion, CC (%) in tree rings show high potential to be established as novel supplementary proxy in dendroclimatology.

  3. Study of Z > 18 elements concentration in tree rings from surroundings forests of the Mexico Valley using external beam PIXE

    International Nuclear Information System (INIS)

    Calva-Vazquez, G.; Razo-Angel, G.; Rodriguez-Fernandez, L.; Ruvalcaba-Sil, J.L.

    2006-01-01

    The concentration of elements with Z > 18 is measured in tree rings from forests at the surroundings of the Mexico Valley: El Chico National Park (ECP) and Desierto de los Leones National Park (DLP). The analysis was done by simultaneous PIXE-RBS using an external proton beam on tree rings of Pine and Sacred fir (species Pinus montezumae and Abies religiosa, respectively). This study provides information about the elemental concentration in trees of those parks during the years from 1965 to 2003. Typical elements such as K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Sr and Pb were detected using PIXE technique while the wood matrix composition (mainly C and O) was determined by RBS. In general, elemental contents present large variations but concentrations oscillate around the mean value during this period of time. Nevertheless, the measurements showed some trends for Fe and Zn in the tree-rings elemental composition that may be correlated to recent volcanic activities in the region. The low Mn contents indicate soil acidification in DLP from 1968 and the forest decline in ECP during the last 15 years

  4. Evaluating the use of strontium isotopes in tree rings to record the isotopic signal of dust deposited on the Wasatch Mountains

    International Nuclear Information System (INIS)

    Miller, Olivia L.; Solomon, Douglas Kip; Fernandez, Diego P.; Cerling, Thure E.; Bowling, David R.

    2014-01-01

    Highlights: • Dust was a major contributor of Sr to soil and tree rings over Sr poor bedrocks. • Tree rings were evaluated for their use as a record of dust strontium isotope history. • The isotopic signal of dust deposited on the Wasatch Mountains changed over the past ∼75 years. - Abstract: Dust cycling from the Great Basin to the Rocky Mountains is an important component of ecological and hydrological processes. We investigated the use of strontium (Sr) concentrations and isotope ratios ( 87 Sr/ 86 Sr) in tree rings as a proxy for dust deposition. We report Sr concentrations and isotope ratios ( 87 Sr/ 86 Sr) from atmospherically deposited dust, soil, bedrock, and tree rings from the Wasatch Mountains to investigate provenance of dust landing on the Wasatch Mountains and to determine if a dust Sr record is preserved in tree rings. Trees obtained a majority of their Sr from dust, making them a useful record of dust source and deposition. Dust contributions of Sr to soils were more than 94% over quartzite, 63% over granodiorite, and 50% over limestone. Dust contributions of Sr to trees were more than 85% in trees growing over quartzite, 55% over granodiorite, and between 0% and 92% over limestone. These findings demonstrate that a dust signal was preserved in some tree rings and reflects how Sr from dust and bedrock mixes within the soil. Trees growing over quartzite were most sensitive to dust. Changes in Sr isotope ratios for a tree growing over quartzite were interpreted as changes in dust source over time. This work has laid the foundation for using tree rings as a proxy for dust deposition over time

  5. Annual global tree cover estimated by fusing optical and SAR satellite observations

    Science.gov (United States)

    Feng, M.; Sexton, J. O.; Channan, S.; Townshend, J. R.

    2017-12-01

    Tree cover defined structurally as the proportional, vertically projected area of vegetation (including leaves, stems, branches, etc.) of woody plants above a given height affects terrestrial energy and water exchanges, photosynthesis and transpiration, net primary production, and carbon and nutrient fluxes. Tree cover provides a measurable attribute upon which forest cover may be defined. Changes in tree cover over time can be used to monitor and retrieve site-specific histories of forest disturbance, succession, and degradation. Measurements of Earth's tree cover have been produced at regional, national, and global extents. However, most representations are static, and those for which multiple time periods have been produced are neither intended nor adequate for consistent, long-term monitoring. Moreover, although a substantial proportion of change has been shown to occur at resolutions below 250 m, existing long-term, Landsat-resolution datasets are either produced as static layers or with annual, five- or ten-year temporal resolution. We have developed an algorithms to retrieve seamless and consistent, sub-hectare resolution estimates of tree-canopy from optical and radar satellite data sources (e.g., Landsat, Sentinel-2, and ALOS-PALSAR). Our approach to estimation enables assimilation of multiple data sources and produces estimates of both cover and its uncertainty at the scale of pixels. It has generated the world's first Landsat-based percent tree cover dataset in 2013. Our previous algorithms are being adapted to produce prototype percent-tree and water-cover layers globally in 2000, 2005, and 2010—as well as annually over North and South America from 2010 to 2015—from passive-optical (Landsat and Sentinel-2) and SAR measurements. Generating a global, annual dataset is beyond the scope of this support; however, North and South America represent all of the world's major biomes and so offer the complete global range of environmental sources of error and

  6. Analysis of polycyclic aromatic hydrocarbons in tree-rings of Masson pine (Pinus massoniana L.) from two industrial sites in the Pearl River Delta, south China.

    Science.gov (United States)

    Kuang, Yuan-wen; Zhou, Guo-yi; Wen, Da-zhi; Li, Jiong; Sun, Fang-fang

    2011-09-01

    Concentrations of polycyclic aromatic hydrocarbons (PAHs) were examined and potential sources of PAHs were identified from the dated tree-rings of Masson pine (Pinus massoniana L.) near two industrial sites (Danshuikeng, DSK and Xiqiaoshan, XQS) in the Pearl River Delta of south China. Total concentrations of PAHs (∑PAHs) were revealed with similar patterns of temporal trends in the tree-rings at both sites, suggesting tree-rings recorded the historical variation in atmospheric PAHs. The differences of individual PAHs and of ∑PAHs detected in the tree-rings between the two sites reflected the historical differences of airborne PAHs. Regional changes in industrial activities might contribute to the site-specific and period-specific patterns of the tree-ring PAHs. The diagnostic PAH ratios of Ant/(Ant + PA), FL/(FL + Pyr), and BaA/(BaA + Chr)) revealed that PAHs in the tree-rings at both sites mainly stemmed from the combustion process (pyrogenic sources). Principal component analysis further confirmed that wood burning, coal combustion, diesel, and gasoline-powered vehicular emissions were the dominant contributors of PAHs sources at DSK, while diesel combustion, gasoline and natural gas combustion, and incomplete coal combustion were responsible for the main origins of PAHs at XQS. Tree-ring analysis of PAHs was indicative of PAHs from a mixture of sources of combustion, thus minimizing the bias of short-term active air sampling.

  7. Paleo Data Assimilation of Pseudo-Tree-Ring-Width Chronologies in a Climate Model

    Science.gov (United States)

    Fallah Hassanabadi, B.; Acevedo, W.; Reich, S.; Cubasch, U.

    2016-12-01

    Using the Time-Averaged Ensemble Kalman Filter (EnKF) and a forward model, we assimilate the pseudo Tree-Ring-Width (TRW) chronologies into an Atmospheric Global Circulation model. This study investigates several aspects of Paleo-Data Assimilation (PDA) within a perfect-model set-up: (i) we test the performance of several forward operators in the framework of a PDA-based climate reconstruction, (ii) compare the PDA-based simulations' skill against the free ensemble runs and (iii) inverstigate the skill of the "online" (with cycling) DA and the "off-line" (no-cycling) DA. In our experiments, the "online" (with cycling) PDA approach did not outperform the "off-line" (no-cycling) one, despite its considerable additional implementation complexity. On the other hand, it was observed that the error reduction achieved by assimilating a particular pseudo-TRW chronology is modulated by the strength of the yearly internal variability of the model at the chronology site. This result might help the dendrochronology community to optimize their sampling efforts.

  8. Multi-century variability in the Pacific North American circulation pattern reconstructed from tree rings

    Science.gov (United States)

    Trouet, Valerie; Taylor, Alan H.

    2010-11-01

    We here present a reconstruction (1725-1999) of the winter Pacific North American (PNA) pattern based on three winter climate sensitive tree ring records from the western USA. Positive PNA phases in our record are associated with warm phases of ENSO and PDO and the reorganization of the PNA pattern towards a positive mode is strongest when ENSO and PDO are in phase. Regime shifts in our PNA record correspond to climatic shifts in other proxies of Pacific climate variability, including two well-documented shifts in the instrumental period (1976 and 1923). The correspondence breaks down in the early 19th century, when our record shows a prolonged period of positive PNA, with a peak in 1800-1820. This period corresponds to a period of low solar activity (Dalton Minimum), suggesting a `positive PNA like' response to decreased solar irradiance. The distinct 30-year periodicity that dominates the PNA reconstruction in the 18th century and again from 1875 onwards is disrupted during this period.

  9. A Wireless Fatigue Monitoring System Utilizing a Bio-Inspired Tree Ring Data Tracking Technique

    Directory of Open Access Journals (Sweden)

    Shi Bai

    2014-03-01

    Full Text Available Fatigue, a hot scientific research topic for centuries, can trigger sudden failure of critical structures such as aircraft and railway systems, resulting in enormous casualties as well as economic losses. The fatigue life of certain structures is intrinsically random and few monitoring techniques are capable of tracking the full life-cycle fatigue damage. In this paper, a novel in-situ wireless real-time fatigue monitoring system using a bio-inspired tree ring data tracking technique is proposed. The general framework, methodology, and verification of this intelligent system are discussed in details. The rain-flow counting (RFC method is adopted as the core algorithm which quantifies fatigue damages, and Digital Signal Processing (DSP is introduced as the core module for data collection and analysis. Laboratory test results based on strain gauges and polyvinylidene fluoride (PVDF sensors have shown that the developed intelligent system can provide a reliable quick feedback and early warning of fatigue failure. With the merits of low cost, high accuracy and great reliability, the developed wireless fatigue sensing system can be further applied to mechanical engineering, civil infrastructures, transportation systems, aerospace engineering, etc.

  10. A wireless fatigue monitoring system utilizing a bio-inspired tree ring data tracking technique.

    Science.gov (United States)

    Bai, Shi; Li, Xuan; Xie, Zhaohui; Zhou, Zhi; Ou, Jinping

    2014-03-05

    Fatigue, a hot scientific research topic for centuries, can trigger sudden failure of critical structures such as aircraft and railway systems, resulting in enormous casualties as well as economic losses. The fatigue life of certain structures is intrinsically random and few monitoring techniques are capable of tracking the full life-cycle fatigue damage. In this paper, a novel in-situ wireless real-time fatigue monitoring system using a bio-inspired tree ring data tracking technique is proposed. The general framework, methodology, and verification of this intelligent system are discussed in details. The rain-flow counting (RFC) method is adopted as the core algorithm which quantifies fatigue damages, and Digital Signal Processing (DSP) is introduced as the core module for data collection and analysis. Laboratory test results based on strain gauges and polyvinylidene fluoride (PVDF) sensors have shown that the developed intelligent system can provide a reliable quick feedback and early warning of fatigue failure. With the merits of low cost, high accuracy and great reliability, the developed wireless fatigue sensing system can be further applied to mechanical engineering, civil infrastructures, transportation systems, aerospace engineering, etc.

  11. A Performance Comparison of Tree and Ring Topologies in Distributed System

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Min [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    A distributed system is a collection of computers that are connected via a communication network. Distributed systems have become commonplace due to the wide availability of low-cost, high performance computers and network devices. However, the management infrastructure often does not scale well when distributed systems get very large. Some of the considerations in building a distributed system are the choice of the network topology and the method used to construct the distributed system so as to optimize the scalability and reliability of the system, lower the cost of linking nodes together and minimize the message delay in transmission, and simplify system resource management. We have developed a new distributed management system that is able to handle the dynamic increase of system size, detect and recover the unexpected failure of system services, and manage system resources. The topologies used in the system are the tree-structured network and the ring-structured network. This thesis presents the research background, system components, design, implementation, experiment results and the conclusions of our work. The thesis is organized as follows: the research background is presented in chapter 1. Chapter 2 describes the system components, including the different node types and different connection types used in the system. In chapter 3, we describe the message types and message formats in the system. We discuss the system design and implementation in chapter 4. In chapter 5, we present the test environment and results, Finally, we conclude with a summary and describe our future work in chapter 6.

  12. Comparing forest measurements from tree rings and a space-based index of vegetation activity in Siberia

    International Nuclear Information System (INIS)

    Bunn, Andrew G; Hughes, Malcolm K; Losleben, Mark; Kirdyanov, Alexander V; Shishov, Vladimir V; Vaganov, Eugene A; Berner, Logan T; Oltchev, Alexander

    2013-01-01

    Different methods have been developed for measuring carbon stocks and fluxes in the northern high latitudes, ranging from intensively measured small plots to space-based methods that use reflectance data to drive production efficiency models. The field of dendroecology has used samples of tree growth from radial increments to quantify long-term variability in ecosystem productivity, but these have very limited spatial domains. Since the cambium material in tree cores is itself a product of photosynthesis in the canopy, it would be ideal to link these two approaches. We examine the associations between the normalized differenced vegetation index (NDVI) and tree growth using 19 pairs of tree-ring widths (TRW) and maximum latewood density (MXD) across much of Siberia. We find consistent correlations between NDVI and both measures of tree growth and no systematic difference between MXD and TRW. At the regional level we note strong correspondence between the first principal component of tree growth and NDVI for MXD and TRW in a temperature-limited bioregion, indicating that canopy reflectance and cambial production are broadly linked. Using a network of 21 TRW chronologies from south of Lake Baikal, we find a similarly strong regional correspondence with NDVI in a markedly drier region. We show that tree growth is dominated by variation at decadal and multidecadal time periods, which the satellite record is incapable of recording given its relatively short record. (letter)

  13. Extreme pointer years in tree-ring records of Central Spain as evidence of climatic events and the eruption of the Huaynaputina Volcano (Peru, 1600 AD

    Directory of Open Access Journals (Sweden)

    M. Génova

    2012-04-01

    Full Text Available The study of pointer years of numerous tree-ring chronologies of the central Iberian Peninsula (Sierra de Guadarrama could provide complementary information about climate variability over the last 405 yr. In total, 64 pointer years have been identified: 30 negative (representing minimum growths and 34 positive (representing maximum growths, the most significant of these being 1601, 1963 and 1996 for the negative ones, and 1734 and 1737 for the positive ones. Given that summer precipitation was found to be the most limiting factor for the growth of Pinus in the Sierra de Guadarrama in the second half of the 20th century, it is also an explanatory factor in almost 50% of the extreme growths. Furthermore, these pointer years and intervals are not evenly distributed throughout time. Both in the first half of the 17th and in the second half of 20th, they were more frequent and more extreme and these periods are the most notable for the frequency of negative pointer years in Central Spain. The interval 1600–1602 is of special significance, being one of the most unfavourable for tree growth in the centre of Spain, with 1601 representing the minimum index in the regional chronology. We infer that this special minimum annual increase was the effect of the eruption of Huaynaputina, which occurred in Peru at the beginning of 1600 AD. This is the first time that the effects of this eruption in the tree-ring records of Southern Europe have been demonstrated.

  14. Evidence of 11-year solar cycles in tree rings from 1010 to 1110 AD - Progress on high precision AMS measurements

    Energy Technology Data Exchange (ETDEWEB)

    Guettler, D., E-mail: guettler@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, HPK G31, Schafmattstrasse 20, 8093 Zurich (Switzerland); Wacker, L. [Laboratory of Ion Beam Physics, ETH Zurich, HPK G31, Schafmattstrasse 20, 8093 Zurich (Switzerland); Kromer, B.; Friedrich, M. [Heidelberg Academy of Sciences, 69120 Heidelberg (Germany); Institute of Botany, University of Hohenheim, 70593 Stuttgart (Germany); Synal, H.-A. [Laboratory of Ion Beam Physics, ETH Zurich, HPK G31, Schafmattstrasse 20, 8093 Zurich (Switzerland)

    2013-01-15

    Oak tree rings from Southern Germany covering the AD 1010-1110 years have been analyzed for radiocarbon with accelerator mass spectrometry (AMS) at the laboratory at ETH Zurich. High-precision measurements with a precision down to 12 years radiocarbon age and a time resolution of 2 years aimed to identify modulations of the {sup 14}C concentration in tree ring samples caused by the 11 years solar cycles, a feature that so far is not visible in the IntCal calibration curve. Our results are in good agreement with the current calibration curve IntCal09. However, we observed an offset in radiocarbon age of 25-40 years towards older values. An evaluation of our sample preparation, that included variations of e.g.: chemicals, test glasses and processing steps did not explain this offset. The numerous measurements using the AMS-MICADAS system validated its suitability for high precision measurements with high repeatability.

  15. Tree-Rings Mirror Management Legacy: Dramatic Response of Standard Oaks to Past Coppicing in Central Europe

    Czech Academy of Sciences Publication Activity Database

    Altman, Jan; Hédl, Radim; Szabó, Péter; Mazůrek, Petr; Riedl, Vladan; Müllerová, Jana; Kopecký, Martin; Doležal, Jiří

    2013-01-01

    Roč. 8, č. 2 (2013), e55770 E-ISSN 1932-6203 R&D Projects: GA ČR GAP504/12/1952; GA AV ČR IAA600050812; GA MŠk(CZ) EE2.3.20.0267 Institutional support: RVO:67985939 Keywords : tree-rings * coppicing * competition Subject RIV: EH - Ecology, Behaviour Impact factor: 3.534, year: 2013

  16. Exploring Relationships among Tree-Ring Growth, Climate Variability, and Seasonal Leaf Activity on Varying Timescales and Spatial Resolutions

    OpenAIRE

    Bhuyan, Upasana;Zang, Christian;Vicente-Serrano, Sergio;Menzel, Annette

    2018-01-01

    In the first section of this study, we explored the relationship between ring width index (RWI) and normalized difference vegetation index (NDVI) time series on varying timescales and spatial resolutions, hypothesizing positive associations between RWI and current and previous- year NDVI at 69 forest sites scattered in the Northern Hemisphere. We noted that the relationship between RWI and NDVI varies over space and between tree types (deciduous versus coniferous), bioclimatic zones, cumulati...

  17. A new tree-ring-based summer temperature reconstruction over the last three centuries for east-central Europe

    Czech Academy of Sciences Publication Activity Database

    Treml, V.; Ponočná, T.; King, G. M.; Büntgen, Ulf

    2015-01-01

    Roč. 35, č. 10 (2015), s. 3160-3171 ISSN 0899-8418 R&D Projects: GA MŠk(CZ) EE2.3.20.0248 Institutional support: RVO:67179843 Keywords : high-resolution paleoclimatology * climate * growth * standardization * records * millennium * mountains * responses * density * signal * tree rings * climate reconstruction * dendroclimatology * documentary evidence * Little Ice Age * warm ing * Norway spruce * proxy archives * Sudetes Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.609, year: 2015

  18. Exploring Relationships among Tree-Ring Growth, Climate Variability, and Seasonal Leaf Activity on Varying Timescales and Spatial Resolutions

    OpenAIRE

    Upasana Bhuyan; Christian Zang; Sergio M. Vicente-Serrano; Annette Menzel

    2017-01-01

    In the first section of this study, we explored the relationship between ring width index (RWI) and normalized difference vegetation index (NDVI) time series on varying timescales and spatial resolutions, hypothesizing positive associations between RWI and current and previous- year NDVI at 69 forest sites scattered in the Northern Hemisphere. We noted that the relationship between RWI and NDVI varies over space and between tree types (deciduous versus coniferous), bioclimatic zones, cumulati...

  19. Reconstructing Century-Scale Changes in Nitrogen Cycling in Forests Throughout the United States using Tree-Ring δ15N Chronologies

    Science.gov (United States)

    Gerhart-Barley, L.; McLauchlan, K. K.; Battles, J. J.; Craine, J. M.; Higuera, P. E.; Mack, M. C.; McNeil, B. E.; Nelson, D. M.; Pederson, N.; Perakis, S. S.

    2016-12-01

    In recent decades, human perturbation of the global nitrogen (N) cycle has been immense with reactive nitrogen supply to ecosystems from anthropogenic sources now exceeding that of natural fixation. The impact of these perturbations on ecosystem nutrient cycling and plant communities is limited by the lack of long-term `baseline' assessments of N cycling prior to anthropogenic influences. Stable N isotope analysis (δ15N) of dendrochronological records have the potential to provide this baseline data, but to date have focused on short term, regional assessments. Here, we address this question with a data set incorporating 311 individual trees and 7,661 δ15N measurements from 50 sites throughout the contiguous United States. These sites represent the diversity of US forest types, climate conditions, N deposition, soil types, and disturbance histories. The chronologies span, on average, the last 162 calendar years, with the oldest chronology dating back to 1572 C.E. Consequently, this study is the first century- and continental-scale assessment of ecosystem N cycling using tree-ring chronologies. When aggregated, the chronologies show a consistent decline from 1825 C.E. to present, indicating declining N availability in US forests, despite global increases in N supply. Environmental factors such as mean annual precipitation (MAP), mean annual temperature (MAT), and mean annual nitrogen deposition (Ndep) did not contribute to average site δ15N values; however, MAP and MAT significantly affected temporal trajectories in tree-ring δ15N, with more negative slopes toward present occurring in regions with low MAT and high MAP. Quantity of atmospheric N deposition had no discernible impact on mean δ15N values or on the temporal slope. This lack of response is either because levels of N deposition are too low to produce a discernible response in any meaningful aspects of the N cycle, and/or the δ15N signature of depositional N is similar enough to ecosystem N pools that

  20. Combining tree-ring metal concentrations and lead, carbon and oxygen isotopes to reconstruct peri-urban atmospheric pollution

    Directory of Open Access Journals (Sweden)

    Annick Doucet

    2012-08-01

    Full Text Available In this study, we analysed the tree-ring metal concentrations and isotope ratios of five stands located in three contrasted settings to infer the diffuse air pollution history of the northern part of the Windsor–Québec City Corridor in eastern Canada. Tree-ring series show that the Cd and Zn accumulation rates were higher between 1960 and 1986 and that the long-term acidification of the soil (Ca/Al series was likely induced by NOx and SOx deposition (δ15N and δ13C trends as proxy. The Pb concentrations and 206Pb/207Pb ratios indicate that the dominant source of lead from 1880 to the 1920s was the combustion of north-eastern American coal, which was succeeded by the combustion of leaded gasoline from the 1920s to the end of the 1980s. Our modelling approach allows separating the climatic and anthropogenic effects on the tree-ring δ13C and δ18O responses. Diffuse air pollution caused an enrichment in 13C in all stands and a decrease of the δ18O values only in three of the stands. This study indicates that dendrogeochemistry can show contrasted responses to environmental changes and that the combination of several independent indicators constitutes a powerful tool to reconstruct the air pollution history in the complex context of peri-urban regions.

  1. Determination of As in tree-rings of poplar (Populus alba L.) by U-shaped DC arc.

    Science.gov (United States)

    Marković, D M; Novović, I; Vilotić, D; Ignjatović, Lj

    2009-04-01

    An argon-stabilized U-shaped DC arc with a system for aerosol introduction was used for determination of As in poplar (Populus alba L.) tree-rings. After optimization of the operating parameters and selection of the most appropriate signal integration time (30 s), the limit of detection for As was reduced to 15.0 ng/mL. This detection limit obtained with the optimal integration time was compared with those for other methods: inductively coupled plasma-atomic emission spectrometry (ICP-AES), direct coupled plasma-atomic emission spectrometry (DCP-AES), microwave induced plasma-atomic emission spectrometry (MIP-AES) and improved thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS). Arsenic is toxic trace element which can adversely affect plant, animal and human health. As an indicator of environment pollution we collected poplar tree-rings from two locations. The first area was close to the "Nikola Tesla" (TENT-A) power plant, Obrenovac, while the other was in the urban area of Novi Sad. In all cases elevated average concentrations of As were registered in poplar tree-rings from the Obrenovac location.

  2. There is no temperature dependence of net biochemical fractionation of hydrogen and oxygen isotopes in tree-ring cellulose.

    Science.gov (United States)

    Roden, J S; Ehleringer, J R

    2000-01-01

    The isotopic composition of tree-ring cellulose was obtained over a two-year period from small diameter, riparian zone trees along an elevational transect in Big Cottonwood Canyon, Utah, USA to test for a possible temperature dependence of net biological fractionation during cellulose synthesis. The isotope ratios of stream water varied by only 3.6% and 0.2% in deltaD and delta18O, respectively, over an elevation change of 810m. The similarity in stream water and macroenvironment over the short (13km) transect produced nearly constant stem and leaf water deltaD and delta18O values. In addition, what few seasonal variations observed in the isotopic composition of source water and atmospheric water vapor or in leaf water evaporative enrichment were experienced equally by all sites along the elevational transect. The temperature at each site along the transect spanned a range of > or = 5 degrees C as calculated using the adiabatic lapse rate. Since the deltaD and delta18O values of stem and leaf water varied little for these trees over this elevation/temperature transect, any differences in tree-ring cellulose deltaD and delta18O values should have been associated with temperature effects on net biological fractionation. However, the slopes of the regressions of elevation versus the deltaD and delta18O values of tree-ring cellulose were not significantly different from zero indicating little or no temperature dependence of net biological fractionation. Therefore, cross-site climatic reconstruction studies using the isotope ratios of cellulose need not be concerned that temperatures during the growing season have influenced results.

  3. [Tree-ring growth responses of Mongolian oak (Quercus mongolica) to climate change in southern northeast: a case study in Qianshan Mountains].

    Science.gov (United States)

    Teng, Li; Xing-Yuan, He; Zhen-Ju, Chen

    2014-07-01

    Mongolian oak is one of the most important broad-leaved tree species in forests, Northeast China. Based on the methodology of dendrochronology, the variations of tree ring radial growth of Mongolian oak in Qianshan Mountains, south of Northeast China, were analyzed. Combined with the temperature and precipitation data from meteorological stations since 1951, the relationships between standardized tree ring width chronology and main climatic factors were analyzed. In this region, the precipitation between April and July of the current year had an significant relationship with the tree ring width of Mongolian oak, and was the main factor limiting the radial growth. The extreme maximum temperature of May was also a key factor influencing the tree ring width, which had a significant on the tree ring width of Mongolian oak. The precipitation in April had a significant and stable relationship with the growth of Mongolian oak since the 1950s. The 'divergence problem' was found in the study area, which the sensitivity of tree growth to summer temperature reduced since the 1980s. The tree growth response to temperature showed a seasonal change from summer to spring.

  4. Using Tree-Rings and Remote Sensing to Investigate Forest Productivity Response to Landscape Fragmentation in Northeastern Algeria

    Science.gov (United States)

    Rouini, N.; Lepley, K. S.; Messaoudene, M.

    2017-12-01

    Remote sensing and dendrochronology are valuable tools in the face of climate change and land use change, yet the connection between these resources remains largely unexploited. Research on forest fragmentation is mainly focused on animal groups, while our work focuses on tree communities. We link tree-rings and remotely-sensed Normalized Difference Vegetation Index (NDVI) using seasonal correlation analysis to investigate forest primary productivity response to fragmentation. Tree core samples from Quercus afares have been taken from two sites within the Guerrouche Forest in northeastern Algeria. The first site is located within a very fragmented area while the second site is intact. Fragmentation is estimated to have occurred with the construction of a road in 1930. We find raw tree-ring width chronologies from each site reveal growth release in the disturbed site after 1930. The means of each chronology for the 1930 to 2016 period are statistically different (p < 0.01). Based on these preliminary results we hypothesize that reconstructed primary productivity (NDVI) will be higher in the fragmented site after fragmentation took place.

  5. Population differentiation in tree-ring growth response of white fir (Abies concolor) to climate: Implications for predicting forest responses to climate change

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Deborah Bowne [Univ. of California, Berkeley, CA (United States)

    1993-01-01

    Forest succession models and correlative models have predicted 200--650 kilometer shifts in the geographic range of temperate forests and forest species as one response to global climate change. Few studies have investigated whether population differences may effect the response of forest species to climate change. This study examines differences in tree-ring growth, and in the phenotypic plasticity of tree-ring growth in 16-year old white fir, Abies concolor, from ten populations grown in four common gardens in the Sierra Nevada of California. For each population, tree-ring growth was modelled as a function of precipitation and degree-day sums. Tree-ring growth under three scenarios of doubled CO2 climates was estimated.

  6. Tree-ring reconstruction of streamflow in the Snare River Basin, Northwest Territories, Canada

    Science.gov (United States)

    Martin, J. P.; Pisaric, M. F.

    2017-12-01

    Drought is a component of many ecosystems in North America causing environmental and socioeconomical impacts. In the ongoing context of climatic and environmental changes, drought-related issues are becoming problematic in northern Canada, which have not been associated with drought-like conditions in the past. Dryer than average conditions threatens the energy security of northern canadian communities, since this region relies on the production of hydroelectricity as an energy source. In the North Slave Region of Northwest Territory (NWT), water levels and streamflows were significantly lower in 2014/2015. The Government of the NWT had to spend nearly $50 million to purchase diesel fuel to generate enough electricity to supplement the reduced power generation of the Snare River hydroelectric system, hence the need to better understand the multi-decadal variability in streamflow. The aims of this presentation are i) to present jack pine and white spruce tree-ring chronologies of Southern NWT; ii) to reconstruct past streamflow of the Snare River Basin; iii) to evaluate the frequency and magnitude of extreme drought conditions, and iv) to identify which large-scale atmospheric or oceanic patterns are teleconnected to regional hydraulic conditions. Preliminary results show that the growth of jack pine and white spruce populations is better correlated with precipitation and temperature, respectively, than hydraulic conditions. Nonetheless, we present a robust streamflow reconstruction of the Snare River that is well correlated with the summer North Atlantic Oscillation (NAO) index, albeit the strength of the correlation is non-stationary. Spectral analysis corroborate the synchronicity between negative NAO conditions and drought conditions. From an operational standpoint, considering that the general occurrence of positive/negative NAO can be predicted, it the hope of the authors that these results can facilitate energetic planning in the Northwest Territories through

  7. Mexican drought: an observational modeling and tree ring study of variability and climate change

    Energy Technology Data Exchange (ETDEWEB)

    Seager, R.; Ting, M. [Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY (United States)]. E-mail: seager@ldeo.columbia.edu; Davis, M. [Department of History, University of California at Irvine, CA (United States); Cane, M.; Naik, N.; Nakamura, J.; Li, C.; Cook, E. [Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY (United States); Stahle, D.W. [Tree Ring Laboratory, University of Arkansas, Fayetteville, Arkansas (United States)

    2009-01-15

    Variability of Mexican hydroclimate, with special attention to persistent drought, is examined using observations, model simulations forced by historical sea surface temperature (SST), tree ring reconstructions of past climate and model simulations and projections of naturally and anthropogenically forced climate change. During the winter half year, hydroclimate across Mexico is influenced by the state of the tropical Pacific Ocean with the Atlantic playing little role. Mexican winters tend to be wetter during El Nino conditions. In the summer half year northern Mexico is also wetter when El Nino conditions prevail, but southern Mexico is drier. A warm tropical North Atlantic Ocean makes northern Mexico dry and southern Mexico wet. These relationships are reasonably well reproduced in ensembles of atmosphere model simulations forced by historical SST for the period from 1856 to 2002. Large ensembles of 100 day long integrations are used to examine the day to day evolution of the atmospheric circulation and precipitation in response to a sudden imposition of a El Nino SST anomaly in the summer half year. Kelvin waves propagate east and immediately cause increased column-integrated moisture divergence and reduced precipitation over the tropical Americas and Intra-America Seas. Within a few days a low level high pressure anomaly develops over the Gulf of Mexico. A forced nonlinear model is used to demonstrate that this low is forced by the reduced atmospheric heating over the tropical Atlantic-Intra-America Seas area. Tree ring reconstructions that extend back before the period of instrumental precipitation data coverage are used to verify long model simulations forced by historical SST. The early to mid 1950s drought in northern Mexico appears to have been the most severe since the mid nineteenth century and likely arose as a response to both a multiyear La Nina and a warm tropical North Atlantic. A drought in the 1890s was also severe and appears driven by a

  8. Radiocarbon adjustments to the dendrochronology of a yellowwood tree

    CSIR Research Space (South Africa)

    Vogel, JC

    2001-03-01

    Full Text Available High-precision radiocarbon dating of a millennium-old yellowwood tree from the Midlands of Natal shows that the tree-rings do, in general, record annual growth, but that both missing and false rings occur. At two places along the transect...

  9. Tree-Rings, Timbers and Trees: A dendrochronological survey of the 14th-century cog, Doel 1

    DEFF Research Database (Denmark)

    Haneca, Kristof; Daly, Aoife

    2014-01-01

    In 2000, the remains of a cog, Doel 1, were found in Doel, Belgium. Wood species identification of all ship timbers and smaller elements was performed. European oak was the dominant species, followed by alder that was used for the fairings. In total 150 ring-width series were recorded. The constr......In 2000, the remains of a cog, Doel 1, were found in Doel, Belgium. Wood species identification of all ship timbers and smaller elements was performed. European oak was the dominant species, followed by alder that was used for the fairings. In total 150 ring-width series were recorded...

  10. Oxygen isotopes in tree rings record variation in precipitation δ18O and amount effects in the south of Mexico.

    Science.gov (United States)

    Brienen, Roel J W; Hietz, Peter; Wanek, Wolfgang; Gloor, Manuel

    2013-12-01

    [1] Natural archives of oxygen isotopes in precipitation may be used to study changes in the hydrological cycle in the tropics, but their interpretation is not straightforward. We studied to which degree tree rings of Mimosa acantholoba from southern Mexico record variation in isotopic composition of precipitation and which climatic processes influence oxygen isotopes in tree rings ( δ 18 O tr ). Interannual variation in δ 18 O tr was highly synchronized between trees and closely related to isotopic composition of rain measured at San Salvador, 710 km to the southwest. Correlations with δ 13 C, growth, or local climate variables (temperature, cloud cover, vapor pressure deficit (VPD)) were relatively low, indicating weak plant physiological influences. Interannual variation in δ 18 O tr correlated negatively with local rainfall amount and intensity. Correlations with the amount of precipitation extended along a 1000 km long stretch of the Pacific Central American coast, probably as a result of organized storm systems uniformly affecting rainfall in the region and its isotope signal; episodic heavy precipitation events, of which some are related to cyclones, deposit strongly 18 O-depleted rain in the region and seem to have affected the δ 18 O tr signal. Large-scale controls on the isotope signature include variation in sea surface temperatures of tropical north Atlantic and Pacific Ocean. In conclusion, we show that δ 18 O tr of M . acantholoba can be used as a proxy for source water δ 18 O and that interannual variation in δ 18 O prec is caused by a regional amount effect. This contrasts with δ 18 O signatures at continental sites where cumulative rainout processes dominate and thus provide a proxy for precipitation integrated over a much larger scale. Our results confirm that processes influencing climate-isotope relations differ between sites located, e.g., in the western Amazon versus coastal Mexico, and that tree ring isotope records can help in

  11. Functional adjustments of xylem anatomy to climatic variability: insights from long-term Ilex aquifolium tree-ring series.

    Science.gov (United States)

    Rita, Angelo; Cherubini, Paolo; Leonardi, Stefano; Todaro, Luigi; Borghetti, Marco

    2015-08-01

    The present study assessed the effects of climatic conditions on radial growth and functional anatomical traits, including ring width, vessel size, vessel frequency and derived variables, i.e., potential hydraulic conductivity and xylem vulnerability to cavitation in Ilex aquifolium L. trees using long-term tree-ring time series obtained at two climatically contrasting sites, one mesic site in Switzerland (CH) and one drought-prone site in Italy (ITA). Relationships were explored by examining different xylem traits, and point pattern analysis was applied to investigate vessel clustering. We also used generalized additive models and bootstrap correlation functions to describe temperature and precipitation effects. Results indicated modified radial growth and xylem anatomy in trees over the last century; in particular, vessel frequency increased markedly at both sites in recent years, and all xylem traits examined, with the exception of xylem cavitation vulnerability, were higher at the CH mesic compared with the ITA drought site. A significant vessel clustering was observed at the ITA site, which could contribute to an enhanced tolerance to drought-induced embolism. Flat and negative relationships between vessel size and ring width were observed, suggesting carbon was not allocated to radial growth under conditions which favored stem water conduction. Finally, in most cases results indicated that climatic conditions influenced functional anatomical traits more substantially than tree radial growth, suggesting a crucial role of functional xylem anatomy in plant acclimation to future climatic conditions. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. (15)N in tree rings as a bio-indicator of changing nitrogen cycling in tropical forests: an evaluation at three sites using two sampling methods.

    Science.gov (United States)

    van der Sleen, Peter; Vlam, Mart; Groenendijk, Peter; Anten, Niels P R; Bongers, Frans; Bunyavejchewin, Sarayudh; Hietz, Peter; Pons, Thijs L; Zuidema, Pieter A

    2015-01-01

    Anthropogenic nitrogen deposition is currently causing a more than twofold increase of reactive nitrogen input over large areas in the tropics. Elevated (15)N abundance (δ(15)N) in the growth rings of some tropical trees has been hypothesized to reflect an increased leaching of (15)N-depleted nitrate from the soil, following anthropogenic nitrogen deposition over the last decades. To find further evidence for altered nitrogen cycling in tropical forests, we measured long-term δ(15)N values in trees from Bolivia, Cameroon, and Thailand. We used two different sampling methods. In the first, wood samples were taken in a conventional way: from the pith to the bark across the stem of 28 large trees (the "radial" method). In the second, δ(15)N values were compared across a fixed diameter (the "fixed-diameter" method). We sampled 400 trees that differed widely in size, but measured δ(15)N in the stem around the same diameter (20 cm dbh) in all trees. As a result, the growth rings formed around this diameter differed in age and allowed a comparison of δ(15)N values over time with an explicit control for potential size-effects on δ(15)N values. We found a significant increase of tree-ring δ(15)N across the stem radius of large trees from Bolivia and Cameroon, but no change in tree-ring δ(15)N values over time was found in any of the study sites when controlling for tree size. This suggests that radial trends of δ(15)N values within trees reflect tree ontogeny (size development). However, for the trees from Cameroon and Thailand, a low statistical power in the fixed-diameter method prevents to conclude this with high certainty. For the trees from Bolivia, statistical power in the fixed-diameter method was high, showing that the temporal trend in tree-ring δ(15)N values in the radial method is primarily caused by tree ontogeny and unlikely by a change in nitrogen cycling. We therefore stress to account for tree size before tree-ring δ(15)N values can be properly

  13. 15N in tree rings as a bio-indicator of changing nitrogen cycling in tropical forests: an evaluation at three sites using two sampling methods

    Directory of Open Access Journals (Sweden)

    Peter evan der Sleen

    2015-04-01

    Full Text Available Anthropogenic nitrogen deposition is currently causing a more than twofold increase of reactive nitrogen input over large areas in the tropics. Elevated 15N abundance (δ15N in the growth rings of some tropical trees has been hypothesized to reflect an increased leaching of 15N-depleted nitrate from the soil following anthropogenic nitrogen deposition over the last decades. To find further evidence for altered nitrogen cycling in tropical forests we measured long-term δ15N values in trees from Bolivia, Cameroon and Thailand. We used two different sampling methods. In the first, wood samples were taken in a conventional way: from the pit to the bark across the stem of 28 large trees (the ‘radial’ method. In the second, δ15N values were compared across a fixed diameter (the ‘fixed-diameter’ method. We sampled 400 trees that differed widely in size, but measured δ15N in the stem around the same diameter (20 cm dbh in all trees. As a result, the growth rings formed around this diameter differed in age and allowed a comparison of δ15N values over time with an explicit control for the potential size-effects on δ15N values. We found a significant increase of tree-ring δ15N across the stem radius of large trees from Bolivia and Cameroon, but no change in tree-ring δ15N values over time was found in any of the study sites when controlling for tree size. This suggests that radial trends of δ15N values within trees reflect tree ontogeny (size development. However, for the trees from Cameroon and Thailand, a low statistical power in the fixed-diameter method prevents to conclude this with high certainty. For the trees from Bolivia, statistical power in the fixed-diameter method was high, showing that the temporal trend in tree-ring δ15N values in the radial method is primarily caused by tree ontogeny and unlikely by a change in nitrogen cycling. We therefore stress to account for tree size before tree-ring δ15N values can be properly

  14. Drought-associated tree mortality: Global patterns and insights from tree-ring studies in the southwestern U.S.A

    Science.gov (United States)

    Macalady, Alison Kelly

    Forests play an important role in the earth system, regulating climate, maintaining biodiversity, and provisioning human communities with water, food and fuel. Interactions between climate and forest dynamics are not well constrained, and high uncertainty characterizes projections of global warming impacts on forests and associated ecosystem services. Recently observed tree mortality and forest die-off forewarn an acceleration of forest change with rising temperature and increased drought. However, the processes leading to tree death during drought are poorly understood, limiting our ability to anticipate future forest dynamics. The objective of this dissertation was to improve understanding of drought-associated tree mortality through literature synthesis and tree-ring studies on trees that survived and died during droughts in the southwestern USA. Specifically, this dissertation 1) documented global tree mortality patterns and identified emerging trends and research gaps; 2) quantified relationships between growth, climate, competition and mortality of pinon pine during droughts in New Mexico; 3) investigated tree defense anatomy as a potentially key element in pinon avoidance of death; and, 4) characterized the climate sensitivity of pinon resin ducts in order to gain insight into potential trends in tree defenses with climate variability and change. There has been an increase in studies reporting tree mortality linked to drought, heat, and the associated activity of insects and pathogens. Cases span the forested continents and occurred in water, light and temperature-limited forests. We hypothesized that increased tree mortality may be an emerging global phenomenon related to rising temperatures and drought (Appendix A). Recent radial growth was 53% higher on average in pinon that survived versus died during two episodes of drought-associated mortality, and statistical models of mortality risk based on average growth, growth variability, and abrupt growth

  15. Biophysical modelling of intra-ring variations in tracheid features and wood density of Pinus pinaster trees exposed to seasonal droughts

    Science.gov (United States)

    Sarah Wilkinson; Jerome Ogee; Jean-Christophe Domec; Mark Rayment; Lisa Wingate

    2015-01-01

    Process-based models that link seasonally varying environmental signals to morphological features within tree rings are essential tools to predict tree growth response and commercially important wood quality traits under future climate scenarios. This study evaluated model portrayal of radial growth and wood anatomy observations within a mature maritime pine (Pinus...

  16. An investigation of the role of winter and spring precipitation as drivers of streamflow in the Missouri River Headwaters using tree-ring reconstructions

    Science.gov (United States)

    Frederick, S. E.; Woodhouse, C. A.; Martin, J. T.; Pederson, G. T.

    2017-12-01

    The Missouri River supplies water to over 3 million basin residents and is a driving force for the nation's agricultural and energy sectors. However, with changing climate and declining snowpack in western North America, seasonal water yields are becoming less predictable, revealing a gap in our understanding of regional hydroclimate and drivers of streamflow within the basin. By analyzing the relationship between seasonal precipitation and streamflow in the Missouri River Headwaters sub-basin, this study seeks to expand our knowledge based on the instrumental record alone. Here we present the first annually-resolved tree-ring reconstruction of spring precipitation for the Missouri River Headwaters. This reconstruction along with existing tree-ring reconstructions of April 1 snow-water equivalence (SWE) (Pederson et al. 2011) and natural streamflow (Martin, J.T. & Pederson, G.T., personal communication, June 2017) are used to test the feasibility of detecting a variable influence of winter and spring precipitation on streamflow over past centuries, and relative to the modern period. Initial analyses indicate that April 1 SWE is a significant control on streamflow, however, the April 1 SWE record does not fully account for anomalies observed in the streamflow record. This study therefore seeks to determine whether spring precipitation can account for some of this asynchronous variability observed between the April 1 SWE and streamflow records. Aside from improved understanding of the relationship between hydroclimate and streamflow in the headwaters of the Missouri River, our findings offer insights relating to changing contributions from snowmelt and spring precipitation, and long-term hydrologic variability and trends relevant to water resource management and planning efforts.

  17. The Response of Tree-Ring Growth to Climate at Upper Timberline of Southern Aspect of Mt. Taibai

    Directory of Open Access Journals (Sweden)

    Qin Jin

    2016-01-01

    Full Text Available In recent years, the impact of climate change on vegetation in Qinling mountainous area has already been authenticated by numerous investigations, nevertheless, as the major ridge of Qinling Mountains as well as national natural conservation reserve, the ecology response of Mt. Taibai sub-alpine vegetation to climate change has not yet gained enough public attention.In this study, in accordance with the method of dendrochronology, response analysis was carried out to contrast characteristic parameters of tree-ring width chronologies for Larix chinensis from different elevations as well as their response pattern to climate change. The result showed that, Mean sensitivity, standard deviation and variance in first eigenvector are increasing with the rise of elevation, but the correlation coefficients (R1, R2, R3 were decreasing which indicated that the strength of the tree’s common or relative response to environment was decreasing with altitude. Precipitation had stronger correlation with the tree-ring radial growth than air temperature in both of the sites, during the growing season, trees in lower altitude had better correlation with temperature than in higher altitude, thus showing the different response to climate between the two different sites.

  18. Determination of forest growth trends in Komi Republic (northwestern Russia): combination of tree-ring analysis and remote sensing data

    Energy Technology Data Exchange (ETDEWEB)

    Lopatin, E. [Joensuu Univ., Faculty of Forestry, Joensuu (Finland); Kolstroem, T. [Joensuu Univ., Mekrijaervi Research Station, Joensuu (Finland); Spiecker, H. [Univ. of Freiburg, Inst. for Forest Growth, Freiburg (Germany)

    2006-07-01

    It is very important to detect changes in forest productivity due to the global change on a large scale. In this work, the evolution of the vegetation in the Komi Republic (northwestern Russia) from 1982 to 2001 was analyzed using NOAA AVHRR PAL time series. A statistically significant correlation (adjusted r2 = 0.44-0.59) between Normalized Difference Vegetation Index (NDVI) data and tree ring width (261 living trees) was identified for the territory of the Komi Republic. The increased site productivity reflected an increase of integrated NDVI values from June to August. This allows NDVI to be used as a proxy for estimation of forest growth trends for the recent decades. A positive and significant trend in NDVI data was identified from 1982 to 2001, coinciding with an increase in site productivity in the study area. The decrease in precipitations coincided with an increase in site productivity (highest r2 was 0.71). The increase in productivity reflected in NDVI data is maximal on the sites with increased temperature and decreased precipitations. In the Komi Republic the distribution of the trends in NDVI data changes on the south-west to north-east gradient. NDVI data could be used to increase spatial resolution of tree ring width series. Taking into account the relatively small role of human activity in the Komi Republic compared with Europe, the site productivity during recent decades also increased in relatively untouched forests. (orig.)

  19. A feasibility study on the retrospective evaluation of anomalous local tritium fallout by the analysis of tree rings from selected districts in Austria and Hungary

    International Nuclear Information System (INIS)

    Rank, D.

    1987-01-01

    In May 1974 some of the rain samples collected in the Austrian Alps exhibited unusually high tritium concentrations. The monthly mean values ranged up to 360 Bq/kg (3000 TU) compared with the 20-30 Bq/kg background measured in ''normal'' areas. Tree samples have been collected from the exposed area and rings of 1973, 1974 and 1975 were separated. Cellulose prepared from the wood was combusted and the water samples were analysed for tritium by LSC. The results of measurements show that tritium fallout detected in rainfall was reflected in tree rings: a significant increase of tritium concentration was found in the 1974 rings from the exposed area

  20. Did the late spring frost in 2007 and 2011 affect tree-ring width and earlywood vessel size in Pedunculate oak (Quercus robur) in northern Poland?

    Science.gov (United States)

    Puchałka, Radosław; Koprowski, Marcin; Przybylak, Julia; Przybylak, Rajmund; Dąbrowski, Henryk P

    2016-08-01

    Trees are sensitive to extreme weather and environmental conditions. This sensitivity is visible in tree-ring widths and cell structure. In our study, we hypothesized that the sudden frost noted at the beginning of May in both 2007 and 2011 affected cambial activity and, consequently, the number and size of vessels in the tree rings. It was decided to test this hypothesis after damage to leaves was observed. The applied response function model did not show any significant relationships between spring temperature and growth. However, this method uses average values for long periods and sometimes misses the short-term effects. This is why we decided to study each ring separately, comparing them with rings unaffected by the late frost. Our study showed that the short-term effect of sudden frost in late spring did not affect tree rings and selected cell parameters. The most likely reasons for this are (i) cambial activity producing the earlywood vessels before the occurrence of the observed leaf damage, (ii) the forest micro-climate protecting the trees from the harsh frost and (iii) the temperature decline being too short-lived an event to affect the oaks. On the other hand, the visible damage may be occasional and not affect cambium activity and tree vitality at all. We conclude that oak is well-adapted to this phenomenon.

  1. Air-sea exchange of CO2 in the Gulf of Kutch, northern Arabian Sea based on bomb-carbon in corals and tree rings

    International Nuclear Information System (INIS)

    Chakraborty, S.; Ramesh, R.; Krishnaswami, S.

    1994-01-01

    Radiocarbon analyses were carried out in the annual bands of a 40 year old coral collected from the Gulf of Kutch (22.6degN, 70degE) in the northern Arabian Sea and in the annual rings of a teak tree from Thane (19deg14'N, 73deg24'E) near Bombay. These measurements were made in order to obtain the rates of air-sea exchange of CO 2 and the advective mixing of water in the Gulf of Kutch. The Δ 14 C peak in the Thane tree occurs in the year 1964, with a value of ∼630 part per thousand, significantly lower than that of the mean atmospheric Δ 14 C of the northern hemisphere (∼1000 part per thousand). The radiocarbon time series of the coral was modelled considering the supply of carbon and radiocarbon to the gulf through air-sea exchange and advective water transport from the open Arabian Sea. A reasonable fit for the coral data was obtained with an air-sea CO 2 exchange rate of 11-12 mol m -2 yr -1 , and an advective velocity of 28 m yr -1 between the Arabian Sea and the Gulf of Kutch; this was based on a model generated time series for radiocarbon in the Arabian Sea. The deduced velocity (∼ 28 m yr -1 ) of the advective transport of water between the Gulf and the Arabian Sea is much lower than the surface tidal current velocity in this region, but can be understood in terms of net fluxes of carbon and radiocarbon to the gulf to match the observed coral Δ 14 C time series. (author). 30 refs., 7 figs., 2 tabs

  2. Pollen reconstructions, tree-rings and early climate data from Minnesota, USA: a cautionary tale of bias and signal attentuation

    Science.gov (United States)

    St-Jacques, J. M.; Cumming, B. F.; Smol, J. P.; Sauchyn, D.

    2015-12-01

    High-resolution proxy reconstructions are essential to assess the rate and magnitude of anthropogenic global warming. High-resolution pollen records are being critically examined for the production of accurate climate reconstructions of the last millennium, often as extensions of tree-ring records. Past climate inference from a sedimentary pollen record depends upon the stationarity of the pollen-climate relationship. However, humans have directly altered vegetation, and hence modern pollen deposition is a product of landscape disturbance and climate, unlike in the past with its dominance of climate-derived processes. This could cause serious bias in pollen reconstructions. In the US Midwest, direct human impacts have greatly altered the vegetation and pollen rain since Euro-American settlement in the mid-19th century. Using instrumental climate data from the early 1800s from Fort Snelling (Minnesota), we assessed the bias from the conventional method of inferring climate from pollen assemblages in comparison to a calibration set from pre-settlement pollen assemblages and the earliest instrumental climate data. The pre-settlement calibration set provides more accurate reconstructions of 19th century temperature than the modern set does. When both calibration sets are used to reconstruct temperatures since AD 1116 from a varve-dated pollen record from Lake Mina, Minnesota, the conventional method produces significant low-frequency (centennial-scale) signal attenuation and positive bias of 0.8-1.7 oC, resulting in an overestimation of Little Ice Age temperature and an underestimation of anthropogenic warming. We also compared the pollen-inferred moisture reconstruction to a four-century tree-ring-inferred moisture record from Minnesota and Dakotas, which shows that the tree-ring reconstruction is biased towards dry conditions and records wet periods relatively poorly, giving a false impression of regional aridity. The tree-ring chronology also suggests varve

  3. Flood-Ring Formation and Root Development in Response to Experimental Flooding of Young Quercus robur Trees

    Science.gov (United States)

    Copini, Paul; den Ouden, Jan; Robert, Elisabeth M. R.; Tardif, Jacques C.; Loesberg, Walter A.; Goudzwaard, Leo; Sass-Klaassen, Ute

    2016-01-01

    Spring flooding in riparian forests can cause significant reductions in earlywood-vessel size in submerged stem parts of ring-porous tree species, leading to the presence of ‘flood rings’ that can be used as a proxy to reconstruct past flooding events, potentially over millennia. The mechanism of flood-ring formation and the relation with timing and duration of flooding are still to be elucidated. In this study, we experimentally flooded 4-year-old Quercus robur trees at three spring phenophases (late bud dormancy, budswell, and internode expansion) and over different flooding durations (2, 4, and 6 weeks) to a stem height of 50 cm. The effect of flooding on root and vessel development was assessed immediately after the flooding treatment and at the end of the growing season. Ring width and earlywood-vessel size and density were measured at 25- and 75-cm stem height and collapsed vessels were recorded. Stem flooding inhibited earlywood-vessel development in flooded stem parts. In addition, flooding upon budswell and internode expansion led to collapsed earlywood vessels below the water level. At the end of the growing season, mean earlywood-vessel size in the flooded stem parts (upon budswell and internode expansion) was always reduced by approximately 50% compared to non-flooded stem parts and 55% compared to control trees. This reduction was already present 2 weeks after flooding and occurred independent of flooding duration. Stem and root flooding were associated with significant root dieback after 4 and 6 weeks and mean radial growth was always reduced with increasing flooding duration. By comparing stem and root flooding, we conclude that flood rings only occur after stem flooding. As earlywood-vessel development was hampered during flooding, a considerable number of narrow earlywood vessels present later in the season, must have been formed after the actual flooding events. Our study indicates that root dieback, together with strongly reduced hydraulic

  4. The limited contribution of large trees to annual biomass production in an old-growth tropical forest.

    Science.gov (United States)

    Ligot, Gauthier; Gourlet-Fleury, Sylvie; Ouédraogo, Dakis-Yaoba; Morin, Xavier; Bauwens, Sébastien; Baya, Fidele; Brostaux, Yves; Doucet, Jean-Louis; Fayolle, Adeline

    2018-04-16

    Although the importance of large trees regarding biodiversity and carbon stock in old-growth forests is undeniable, their annual contribution to biomass production and carbon uptake remains poorly studied at the stand level. To clarify the role of large trees in biomass production, we used data of tree growth, mortality, and recruitment monitored during 20 yr in 10 4-ha plots in a species-rich tropical forest (Central African Republic). Using a random block design, three different silvicultural treatments, control, logged, and logged + thinned, were applied in the 10 plots. Annual biomass gains and losses were analyzed in relation to the relative biomass abundance of large trees and by tree size classes using a spatial bootstrap procedure. Although large trees had high individual growth rates and constituted a substantial amount of biomass, stand-level biomass production decreased with the abundance of large trees in all treatments and plots. The contribution of large trees to annual stand-level biomass production appeared limited in comparison to that of small trees. This pattern did not only originate from differences in abundance of small vs. large trees or differences in initial biomass stocks among tree size classes, but also from a reduced relative growth rate of large trees and a relatively constant mortality rate among tree size classes. In a context in which large trees are increasingly gaining attention as being a valuable and a key structural characteristic of natural forests, the present study brought key insights to better gauge the relatively limited role of large trees in annual stand-level biomass production. In terms of carbon uptake, these results suggest, as already demonstrated, a low net carbon uptake of old-growth forests in comparison to that of logged forests. Tropical forests that reach a successional stage with relatively high density of large trees progressively cease to be carbon sinks as large trees contribute sparsely or even

  5. Rooting depth varies differentially in trees and grasses as a function of mean annual rainfall in an African savanna.

    Science.gov (United States)

    Holdo, Ricardo M; Nippert, Jesse B; Mack, Michelle C

    2018-01-01

    A significant fraction of the terrestrial biosphere comprises biomes containing tree-grass mixtures. Forecasting vegetation dynamics in these environments requires a thorough understanding of how trees and grasses use and compete for key belowground resources. There is disagreement about the extent to which tree-grass vertical root separation occurs in these ecosystems, how this overlap varies across large-scale environmental gradients, and what these rooting differences imply for water resource availability and tree-grass competition and coexistence. To assess the extent of tree-grass rooting overlap and how tree and grass rooting patterns vary across resource gradients, we examined landscape-level patterns of tree and grass functional rooting depth along a mean annual precipitation (MAP) gradient extending from ~ 450 to ~ 750 mm year -1 in Kruger National Park, South Africa. We used stable isotopes from soil and stem water to make inferences about relative differences in rooting depth between these two functional groups. We found clear differences in rooting depth between grasses and trees across the MAP gradient, with grasses generally exhibiting shallower rooting profiles than trees. We also found that trees tended to become more shallow-rooted as a function of MAP, to the point that trees and grasses largely overlapped in terms of rooting depth at the wettest sites. Our results reconcile previously conflicting evidence for rooting overlap in this system, and have important implications for understanding tree-grass dynamics under altered precipitation scenarios.

  6. A Standardized Precipitation Evapotranspiration Index Reconstruction in the Taihe Mountains Using Tree-Ring Widths for the Last 283 Years.

    Directory of Open Access Journals (Sweden)

    Yongyong Ma

    Full Text Available Tree-ring samples from Chinese Pine (Pinus tabulaeformis Carr. that were collected in the Taihe Mountains on the western Loess Plateau, China, were used to analyze the effects of climate and drought on radial growth and to reconstruct the mean April-June Standardized Precipitation Evapotranspiration Index (SPEI during the period 1730-2012 AD. Precipitation positively affected tree growth primarily during wet seasons, while temperature negatively affected tree growth during dry seasons. Tree growth responded positively to SPEI at long time scales most likely because the trees were able to withstand water deficits but lacked a rapid response to drought. The 10-month scale SPEI was chosen for further drought reconstruction. A calibration model for the period 1951-2011 explained 51% of the variance in the modeled SPEI data. Our SPEI reconstruction revealed long-term patterns of drought variability and captured some significant drought events, including the severe drought of 1928-1930 and the clear drying trend since the 1950s which were widespread across northern China. The reconstruction was also consistent with two other reconstructions on the western Loess Plateau at both interannual and decadal scales. The reconstructed SPEI series showed synchronous variations with the drought/wetness indices and spatial correlation analyses indicated that this reconstruction could be representative of large-scale SPEI variability in northern China. Period analysis discovered 128-year, 25-year, 2.62-year, 2.36-year, and 2.04-year cycles in this reconstruction. The time-dependency of the growth response to drought should be considered in further studies of the community dynamics. The SPEI reconstruction improves the sparse network of long-term climate records for an enhanced understanding of climatic variability on the western Loess Plateau, China.

  7. A Standardized Precipitation Evapotranspiration Index Reconstruction in the Taihe Mountains Using Tree-Ring Widths for the Last 283 Years

    Science.gov (United States)

    Ma, Yongyong; Liu, Yu; Song, Huiming; Sun, Junyan; Lei, Ying; Wang, Yanchao

    2015-01-01

    Tree-ring samples from Chinese Pine (Pinus tabulaeformis Carr.) that were collected in the Taihe Mountains on the western Loess Plateau, China, were used to analyze the effects of climate and drought on radial growth and to reconstruct the mean April-June Standardized Precipitation Evapotranspiration Index (SPEI) during the period 1730–2012 AD. Precipitation positively affected tree growth primarily during wet seasons, while temperature negatively affected tree growth during dry seasons. Tree growth responded positively to SPEI at long time scales most likely because the trees were able to withstand water deficits but lacked a rapid response to drought. The 10-month scale SPEI was chosen for further drought reconstruction. A calibration model for the period 1951–2011 explained 51% of the variance in the modeled SPEI data. Our SPEI reconstruction revealed long-term patterns of drought variability and captured some significant drought events, including the severe drought of 1928–1930 and the clear drying trend since the 1950s which were widespread across northern China. The reconstruction was also consistent with two other reconstructions on the western Loess Plateau at both interannual and decadal scales. The reconstructed SPEI series showed synchronous variations with the drought/wetness indices and spatial correlation analyses indicated that this reconstruction could be representative of large-scale SPEI variability in northern China. Period analysis discovered 128-year, 25-year, 2.62-year, 2.36-year, and 2.04-year cycles in this reconstruction. The time-dependency of the growth response to drought should be considered in further studies of the community dynamics. The SPEI reconstruction improves the sparse network of long-term climate records for an enhanced understanding of climatic variability on the western Loess Plateau, China. PMID:26207621

  8. New tree-ring evidence for the Late Glacial period from the northern pre-Alps in eastern Switzerland

    Science.gov (United States)

    Reinig, Frederick; Nievergelt, Daniel; Esper, Jan; Friedrich, Michael; Helle, Gerhard; Hellmann, Lena; Kromer, Bernd; Morganti, Sandro; Pauly, Maren; Sookdeo, Adam; Tegel, Willy; Treydte, Kerstin; Verstege, Anne; Wacker, Lukas; Büntgen, Ulf

    2018-04-01

    The rate and magnitude of temperature variability at the transition from the Last Glacial Maximum into the early Holocene represents a natural analog to current and predicted climate change. A limited number of high-resolution proxy archives, however, challenges our understanding of environmental conditions during this period. Here, we present combined dendrochronological and radiocarbon evidence from 253 newly discovered subfossil pine stumps from Zurich, Switzerland. The individual trees reveal ages of 41-506 years and were growing between the Allerød and Preboreal (∼13‧900-11‧300 cal BP). Together with previously collected pines from this region, this world's best preserved Late Glacial forest substantially improves the earliest part of the absolutely dated European tree-ring width chronology between 11‧300 and 11‧900 cal BP. Radiocarbon measurements from 65 Zurich pines between ∼12‧320 and 13‧950 cal BP provide a perspective to prolong the continuous European tree-ring record by another ∼2000 years into the Late Glacial era. These data will also be relevant for pinpointing the Laacher See volcanic eruption (∼12‧900 cal BP) and two major Alpine earthquakes (∼13‧770 and ∼11‧600 cal BP). In summary, this study emphasizes the importance of dating precision and multi-proxy comparison to disentangle environmental signals from methodological noise, particularly during periods of high climate variability but low data availability, such as the Younger Dryas cold spell (∼11‧700 and 12‧900 cal BP).

  9. A rapid cosmic-ray increase in BC 3372-3371 from ancient buried tree rings in China.

    Science.gov (United States)

    Wang, F Y; Yu, H; Zou, Y C; Dai, Z G; Cheng, K S

    2017-11-14

    Cosmic rays interact with the Earth's atmosphere to produce 14 C, which can be absorbed by trees. Therefore, rapid increases of 14 C in tree rings can be used to probe previous cosmic-ray events. By this method, three 14 C rapidly increasing events have been found. Plausible causes of these events include large solar proton events, supernovae, or short gamma-ray bursts. However, due to the lack of measurements of 14 C by year, the occurrence frequency of such 14 C rapidly increasing events is poorly known. In addition, rapid increases may be hidden in the IntCal13 data with five-year resolution. Here we report the result of 14 C measurements using an ancient buried tree during the period between BC 3388 and 3358. We found a rapid increase of about 9‰ in the 14 C content from BC 3372 to BC 3371. We suggest that this event could originate from a large solar proton event.

  10. Unthinned slow-growing ponderosa pine (Pinus ponderosa) trees contain muted isotopic signals in tree rings as compared to thinned trees

    Science.gov (United States)

    We analysed the oxygen isotopic values of wood (δ18Ow) of 12 ponderosa pine (Pinus ponderosa) trees from control, moderately, and heavily thinned stands and compared them with existing wood-based estimates of carbon isotope discrimination (∆13C), basal area increment (BAI), and g...

  11. Characterization of sulfur deposition over the period of industrialization in Japan using sulfur isotope ratio in Japanese cedar tree rings taken from stumps.

    Science.gov (United States)

    Ishida, Takuya; Tayasu, Ichiro; Takenaka, Chisato

    2015-07-01

    We characterized the sulfur deposition history over the period of industrialization in Japan based on the sulfur isotope ratio (δ(34)S) in tree rings of Japanese cedar (Cryptomeria japonica D. Don) stumps. We analyzed and compared δ(34)S values in the rings from two types of disk samples from 170-year-old stumps that had been cut 5 years earlier (older forest stand) and from 40-year-old living trees (younger forest stand) in order to confirm the validity of using stump disks for δ(34)S analysis. No differences in δ(34)S values by age were found between the sample types, indicating that stump disks can be used for δ(34)S analysis. The δ(34)S profile in tree rings was significantly correlated with anthropogenic SO2 emissions in Japan (r = -0.76, p tree rings serve as a record of anthropogenic sulfur emissions. In addition, the values did not change largely from pre-industrialization to the 1940s (+4.2 to +6.1‰). The values before the 1940s are expected to reflect the background sulfur conditions in Japan and, thus, disks containing rings formed before the 1940s contain information about the natural environmental sulfur, which is useful for biogeochemical studies.

  12. Tree-ring analysis of teak (Tectona grandis L.F.) in central India and ...

    Indian Academy of Sciences (India)

    ON), current win- ter (DJF), pre-monsoon (MAM), monsoon (JJAS), post-monsoon (ON) and annual series of tempera- ture, rainfall and moisture index. Though the temperature is an important para- meter in photosynthesis, the correlation ...

  13. Distribution of 90Sr in the tree rings of a Japanese cedar exposed to the black rain from the Nagasaki atomic bomb

    International Nuclear Information System (INIS)

    Katayama, Y.; Nagai, M.; Aoki, T.; Nagatomo, T.; Okada, N.

    2006-01-01

    Cedar sample was collected at the black rain area in Nagasaki city. A clear peak of 90 Sr/Sr was observed in the 1924-1925 rings. To investigate the mobility of Sr in a cedar tree stem, strontium chloride solution was injected into a living tree, and the distribution profiles of Sr in the stem at 8 months later were determined. The strontium moves radially through the sapwood of a cedar stem but that it almost stops at the heartwood. It was concluded that the peak in the 1924-1925 rings was due to the black rain from the Nagasaki atomic bomb. (author)

  14. Investigation on the variation of annual ring thicknesses and word densities in South African Pinus radiata stands under the influence of climate and different thinning measures by means of radiodensitometry

    International Nuclear Information System (INIS)

    Bues, C.T.

    1984-01-01

    The present work investigates three phenomena of growth biology in Pinus radiata stands: In the first investigation project: the thickness of the annual rings in relation to climate factors; In the second project: the variability of annual ring thickness and wood density as a function of different thinning measures; In the third project the variability of wood density within a Pinus radiate stand is analyzed. To determine the thickness of the annual rings and the wood density values within the annual rings, the method of radiodensitometry, developed during the last decade, is adopted: In the first investigation project the thicknesses of 800 annual rings are determined, in the second project 3808 annual ring structures are investigated, and in the third project 2000 annual rings are evaluated for their density characteristics. (orig./MG) [de

  15. Tree-rings mirror management legacy: dramatic response of standard oaks to past coppicing in Central Europe.

    Directory of Open Access Journals (Sweden)

    Jan Altman

    Full Text Available BACKGROUND: Coppicing was one of the most important forest management systems in Europe documented in prehistory as well as in the Middle Ages. However, coppicing was gradually abandoned by the mid-20(th century, which has altered the ecosystem structure, diversity and function of coppice woods. METHODOLOGY/PRINCIPAL FINDINGS: Our aim was to disentangle factors shaping the historical growth dynamics of oak standards (i.e. mature trees growing through several coppice cycles in a former coppice-with-standards in Central Europe. Specifically, we tried to detect historical coppicing events from tree-rings of oak standards, to link coppicing events with the recruitment of mature oaks, and to determine the effects of neighbouring trees on the stem increment of oak standards. Large peaks in radial growth found for the periods 1895-1899 and 1935-1939 matched with historical records of coppice harvests. After coppicing, the number of newly recruited oak standards markedly grew in comparison with the preceding or following periods. The last significant recruitment of oak standards was after the 1930s following the last regular coppicing event. The diameter increment of oak standards from 1953 to 2003 was negatively correlated with competition indices, suggesting that neighbouring trees (mainly resprouting coppiced Tilia platyphyllos partly suppressed the growth of oak standards. Our results showed that improved light conditions following historical coppicing events caused significant increase in pulses of radial growth and most probably maintained oak recruitment. CONCLUSIONS/SIGNIFICANCE: Our historical perspective carries important implications for oak management in Central Europe and elsewhere. Relatively intense cutting creating open canopy woodlands, either as in the coppicing system or in the form of selective cutting, is needed to achieve significant radial growth in mature oaks. It is also critical for the successful regeneration and long

  16. Reconstructed Temperature And Precipitation On A Millennial Timescale From Tree-Rings In The Southern Colorado Plateau, U.S.A.

    Energy Technology Data Exchange (ETDEWEB)

    Salzer, M.W. [Laboratory of Tree-Ring Research, The University of Arizona, Tucson, Arizona, 85721 (United States); Kipfmueller, K.F. [Department of Geography, University of Minnesota, Minneapolis, MN, 55455 (United States)

    2005-06-01

    Two independent calibrated and verified climate reconstructions from ecologically contrasting tree-ring sites in the southern Colorado Plateau, U.S.A. reveal decadal-scale climatic trends during the past two millennia. Combining precisely dated annual mean-maximum temperature and October through July precipitation reconstructions yields an unparalleled record of climatic variability. The approach allows for the identification of thirty extreme wet periods and thirty-five extreme dry periods in the 1,425-year precipitation reconstruction and 30 extreme cool periods and 26 extreme warm periods in 2,262-year temperature reconstruction. In addition, the reconstructions were integrated to identify intervals when conditions were extreme in both climatic variables (cool/dry, cool/wet, warm/dry, warm/wet). Noteworthy in the reconstructions are the post-1976 warm/wet period, unprecedented in the 1,425-year record both in amplitude and duration, anomalous and prolonged late 20th century warmth, that while never exceeded, was nearly equaled in magnitude for brief intervals in the past, and substantial decadal-scale variability within the Medieval Warm Period and Little Ice Age intervals.

  17. Oxygen and hydrogen isotope ratios in tree rings: how well do models predict observed values?

    CSIR Research Space (South Africa)

    Waterhouse, JS

    2002-07-30

    Full Text Available . Cosmo- chim. Acta 46 (1982) 955^965. [35] W.M. Buhay, T.W.D. Edwards, Climate in southwestern Ontario, Canada, between AD 1610 and 1885 inferred from oxygen and hydrogen isotopic measurements of wood cellulose from trees in di?erent hydrological set...

  18. Commentary to Wetter et al. (2014): Limited tree-ring evidence for a 1540 European 'Megadrought'

    Czech Academy of Sciences Publication Activity Database

    Büntgen, Ulf; Tegel, W.; Carrera, M.; Krusic, P. J.; Hayes, M.; Esper, J. D.

    2015-01-01

    Roč. 131, č. 2 (2015), s. 183-190 ISSN 0165-0009 Institutional support: RVO:67179843 Keywords : last millennium * documentary evidence * climate sensitivity * forest trees * drought * summer * extremes * temperatures * variability * responses Subject RIV: EH - Ecology, Behaviour Impact factor: 3.344, year: 2015

  19. Changes in Mercury Deposition in a Mining and Smelting Region as Recorded in Tree Rings

    Czech Academy of Sciences Publication Activity Database

    Hojdová, Maria; Navrátil, Tomáš; Rohovec, Jan; Žák, Karel; Vaněk, A.; Chrastný, V.; Bače, R.; Svoboda, M.

    2011-01-01

    Roč. 216, 1/4 (2011), s. 73-82 ISSN 0049-6979 R&D Projects: GA ČR GP526/09/P404 Institutional research plan: CEZ:AV0Z30130516 Keywords : mercury * dendrochemistry * trees * geochemical archives Subject RIV: DD - Geochemistry Impact factor: 1.625, year: 2011

  20. Tree growth inference and prediction from diameter censuses and ring widths

    Science.gov (United States)

    James S. Clark; Michael Wolosin; Michael Dietze; Ines Ibanez; Shannon LaDeau; Miranda Welsh; Brian Kloeppel

    2007-01-01

    Knowledge of tree growth is needed to understand population dynamics (Condit et al. 1993, Fastie 1995, Frelich and Reich 1995, Clark and Clark 1999, Wyckoff and Clark 2002, 2005, Webster and Lorimer 2005), species interactions (Swetnam and Lynch 1993), carbon sequestration (DeLucia et al. 1999, Casperson et al. 2000), forest response to climate change (Cook 1987,...

  1. Virtual private network design : a proof of the tree routing conjecture on ring networks

    NARCIS (Netherlands)

    Hurkens, C.A.J.; Keijsper, J.C.M.; Stougie, L.

    2007-01-01

    A basic question in virtual private network (VPN) design is if the symmetric version of the problem always has an optimal solution which is a tree network. An affirmative answer would imply that the symmetric VPN problem is solvable in polynomial time. We give an affirmative answer in case the

  2. Virtual private network design: a proof of the tree routing conjecture on ring networks

    NARCIS (Netherlands)

    C.A.J. Hurkens (Cor); J.C.M. Keijsper; L. Stougie (Leen)

    2005-01-01

    htmlabstractA basic question in Virtual Private Network (VPN) design is if the symmetric version of the problem always has an optimal solution which is a tree network. An affirmative answer would imply that the symmetric VPN problem is solvable in polynomial time. We give an affirmative answer in

  3. UPDATING THE CZECH MILLENNIA-LONG OAK TREE-RING WIDTH CHRONOLOGY

    Czech Academy of Sciences Publication Activity Database

    Prokop, O.; Kolář, Tomáš; Kyncl, T.; Rybníček, Michal

    2017-01-01

    Roč. 73, č. 1 (2017), s. 47-52 ISSN 1536-1098 R&D Projects: GA ČR GA13-04291S; GA ČR(CZ) GA17-22102S; GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : Belfry construction * Czech Republic * dendrochronology * Quercus * sapwood rings Subject RIV: GK - Forestry OBOR OECD: Forestry Impact factor: 1.769, year: 2016

  4. Stable carbon and oxygen isotope ratios of annual rings of pinus radiata provide an integrative record of canopy gas exchange

    International Nuclear Information System (INIS)

    Barbour, M.M.; Farquhar, G.D.

    2000-01-01

    Full text: Seasonal variation in δ 13 C and δ 18 O of cellulose from annual rings of Pinus radiata growing at each of three sites in New Zealand was measured. The three sites differed in annual water balance, temperature, and vapour pressure deficit, and these differences were reflected in cellulose δ 13 C and δ 18 O. Specific events such as drought or heavy rain were recorded as peaks and troughs in enrichment. A canopy-level combined photosynthesis and conductance model was linked to a model of soil water content and δ 18 O of xylem water to allow daily prediction of δ 13 C and δ 18 O of cellulose. A photosynthesis-weighted average of δ 13 C and δ 18 O was calculated for each sampling period. Each sample represented between 3 and 30 days, depending on stem growth rate. The timing and amplitude of changes in δ 13 C were predicted accurately by the model, while general seasonal patterns and event related peaks in δ 18 O enrichment were well predicted. These results suggest that stable isotope ratios of cellulose from annual rings reflect the canopy response to interactions between site-specific and seasonal variation in climatic conditions and soil water availability

  5. Temperature Signals in Tree-Ring Width Chronologies of Alpine Treeline Conifers from the Baishui River Nature Reserve, China

    Directory of Open Access Journals (Sweden)

    Huiqin Wang

    2013-01-01

    Full Text Available Numerous dendro-climatic reconstructions have been developed for China, but there are still regions with limited data of this type. One region is the Qinling Mountains which is characterized by complex interactions between the mountains and climate. Presently, the subalpine region of the Qinling Mountains is covered by widespread forests and has great potential for dendroclimatological studies. Here we developed tree-ring width chronologies from two fir (Abies faxoniana and one spruce (Picea brachytyla sites in the Baishui River Nature Reserve, the western region of the Qinling Mountains, China. Climate response analysis reveals that radial growth of the fir site (TLD is mainly controlled by temperature variations. The TLD chronology accounts for 32.7% of February - June temperature variance during the period 1959 - 2006. Using a linear regression approach, we reconstructed the February - June temperature of Wen County for the past 252 years. The cool periods are identified for AD 1795 - 1800, 1812 - 1827, 1881 - 1888, 1895 - 1902, 1916 - 1929, 1967 - 1972 and 1978 - 1995. Warm conditions prevailed during AD 1783 - 1794, 1801 - 1811, 1828 - 1856, 1867 - 1880, 1889 - 1894, 1903 - 1915 and 1930 - 1966. Wavelet analysis reveals the existence of some cycles (2.0 - 3.4, 5.7, 10.0 and 19.3 years. Spatial correlation analysis shows that the temperature reconstruction captures regional climatic variations over Central and Southwest China. The moving t-test indicated an abrupt warming change of our reconstruction occurred during the past 20 years. Overall, our study indicates the feasibility of combining tree-rings and the temperature to reconstruct large-scale temperature patterns over this area.

  6. Examining Basin-Scale Water and Climate Relations across the Pampa del Tamarugal, Atacama Desert through Spatial Analysis of Hydrogen, Carbon and Oxygen Isotopes in Tree Rings

    Science.gov (United States)

    Olson, E. J.; Dodd, J. P.; Rivera, M. A.

    2016-12-01

    Arid regions are extremely sensitive to variations hydroclimate. However, our understanding of past hydroclimate variations in these regions is often limited by a paucity of spatially resolved proxy data. The Atacama Desert of northern Chile is one of the driest regions on Earth, and hydroclimatic processes in the Atacama Desert may be a useful proxy for understanding the implications of expanding global aridity. In order to assess the ability of tree-ring isotope studies to record changes in hydrology and terrestrial climate in the Atacama Desert, oxygen (δ18O), carbon (δ13C) and hydrogen (δ2H) isotope values in tree rings of Prosopis tamarugo are analyzed for the modern period (1954-2014) when anthropogenic change to regional groundwater levels have been most notable. Samples of wood cellulose were collected throughout the Pampa del Tamarugal basin from 14 individuals and used to create an interpolated surface of isotope variations. The isotope data were then compared to groundwater depth from well monitoring data provided by the Dirección de General de Agua of Chile. There is a significant correlation between groundwater level and isotope values with best agreement occurring during the past two decades for δ18O (r = 0.58), δ13C (r = 0.55), and δ2H (r = 0.66) values. This spatial correlation analysis reveals that tree ring a-cellulose isotope values are a suitable proxy for reconstructing groundwater depth in the Pampa del Tamarugal Basin. A stepwise multiregression analysis between δ18O values of cellulose and several other environmental variables including groundwater level, relative humidity, and temperature suggest that groundwater depth is the dominate control of variation in the modern δ18O tree ring record. The response of tree cellulose to the hydroclimate in this region suggests that tree ring isotope variations may be used to reconstruct past hydroclimate conditions in arid regions throughout the globe.

  7. Imprints of Climate Signals in a 204 Year δ18O Tree-Ring Record of Nothofagus pumilio From Perito Moreno Glacier, Southern Patagonia (50°S

    Directory of Open Access Journals (Sweden)

    Jussi Grießinger

    2018-04-01

    Full Text Available A 204 year-long record of δ18O in tree-ring cellulose of southern beech (Nothofagus pumilio from a site near Perito Moreno Glacier (50°S in Southern Patagonia was established to assess its potential for a climate reconstruction. The annually resolved oxygen isotope chronology is built out of seven individual tree-ring δ18O series with a significant mean inter-series correlation (r = 0.61 and is the first of its kind located in Southern America south of 50°S. Over a common period from 1960 to 2013 of available stationary and high-resolution gridded CRU TS v. 4.01 data, the δ18O chronology exhibits a strong sensitivity toward hydroclimatic as well as temperature parameters as revealed by correlation analyses. Among these, positive correlations with maximum temperature in the first part of the summer season (CRU rONDJ = 0.51, p < 0.01 and negative correlations with precipitation in the latter half of the vegetation period (CRU rONDJ = −0.54, p < 0.01 show the highest sensitivities. A strong supra-regional influence of the Southern Annular Mode (SAM is clearly recorded in this chronology as indicated by significant positive correlations during the vegetation period (rONDJ = 0.62, p < 0.01. This indicates that the presented δ18O-chronology shows great promise to reconstruct the influence and variability of the SAM within the last two centuries in southern South America. The modulation of positive and negative anomalies within this series can be interlinked to changes in moisture source origin as revealed by backward trajectory modeling. Additionally, these anomalies can be directly associated to positive or negative phases of the Antarctic Oscillation Index (AAOI and therefore the strength of the Westerlies. Aligned by the analysis on the influence of different main weather types on the δ18O chronology it is shown that such time-series hold the potential to additionally capture their respective influence and change during the last centuries.

  8. The use of tree-rings and foliage as an archive of volcanogenic cation deposition

    Energy Technology Data Exchange (ETDEWEB)

    Watt, Sebastian F.L. [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom)]. E-mail: sebastian.watt@earth.ox.ac.uk; Pyle, David M. [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Mather, Tamsin A. [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Day, Jason A. [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Aiuppa, Alessandro [CFTA - Dipt. Chimica e Fisica della Terra e Applicazioni alle Georisorse, Universita degli Studi di Palermo, Via Archirafi 36, 90123 (Italy)

    2007-07-15

    Tree cores (Pinus nigra ssp. laricio) and leaves (Castanea sativa) from the flanks of Mount Etna, Sicily were analysed by ICP-MS to investigate whether volcanogenic cations within plant material provide an archive of a volcano's temporal and spatial depositional influence. There is significant compositional variability both within and between trees, but no systematic dendrochemical correlation with periods of effusive, explosive or increased degassing activity. Dendrochemistry does not provide a record of persistent but fluctuating volcanic activity. Foliar levels of bioaccumulated cations correspond to modelled plume transport patterns, and map short-term volcanic fumigation. Around the flanks of the volcano foliar variation is greater for volatile cations (Cs, Cd, Pb) than for lithophilic cations (Ba, Sr), consistent with trace-metal supply from volcanic aerosol during quiescent periods. - Dendrochemistry does not provide an archive of persistent volcanic activity.

  9. The use of tree-rings and foliage as an archive of volcanogenic cation deposition

    International Nuclear Information System (INIS)

    Watt, Sebastian F.L.; Pyle, David M.; Mather, Tamsin A.; Day, Jason A.; Aiuppa, Alessandro

    2007-01-01

    Tree cores (Pinus nigra ssp. laricio) and leaves (Castanea sativa) from the flanks of Mount Etna, Sicily were analysed by ICP-MS to investigate whether volcanogenic cations within plant material provide an archive of a volcano's temporal and spatial depositional influence. There is significant compositional variability both within and between trees, but no systematic dendrochemical correlation with periods of effusive, explosive or increased degassing activity. Dendrochemistry does not provide a record of persistent but fluctuating volcanic activity. Foliar levels of bioaccumulated cations correspond to modelled plume transport patterns, and map short-term volcanic fumigation. Around the flanks of the volcano foliar variation is greater for volatile cations (Cs, Cd, Pb) than for lithophilic cations (Ba, Sr), consistent with trace-metal supply from volcanic aerosol during quiescent periods. - Dendrochemistry does not provide an archive of persistent volcanic activity

  10. Estimating annual rainfall threshold for establishment of tree species in water-limited ecosystems using tree-ring data

    NARCIS (Netherlands)

    Lopez, B.C.; Holmgren, M.; Sabate, S.; Gracia, C.A.

    2008-01-01

    In arid and semi-arid ecosystems, water availability is discontinuous, highly variable, and characterized by discrete pulse events separated by long periods of limited resource availability. Plant recruitment in these ecosystems is also episodic and dependent on the water available during and after

  11. Tree-Ring Dating of the Reshui-1 Tomb in Dulan County, Qinghai Province, North-west China

    Science.gov (United States)

    LI, M.; Xuemei, S.; Yin, Z. Y.; Xu, X.

    2015-12-01

    Tuyuhun and Tubo were two important states that thrived in north-western China during AD 311-900 in parallel with the Han Chinese dynasties of Sui and Tang periods. The Reshui Tomb Cluster located in Dulan County of the north-eastern Tibetan Plateau is an important cultural relic of the Tuyuhun-Tubo age. The official excavations of the Reshui tombs were regarded as top events in archaeology in the 1980s and 1990s in China. The Reshui-1 Tomb is the largest one among the tombs in the area. Since its excavation, there have been debates on whether the owner of the tomb belonged to the Tuyuhun or Tubo ethnicity. Therefore, accurately dating the Reshui-1 Tomb has a critical place in studying the Tubo and Tuyuhun histories. We collected 7 discs and 11 increment cores of Qilian juniper (Juniperus przewalskii Kom.) from the exposed and fallen beams of the roof of the Reshui-1Tomb. The lengths of the 16 tree-ring records are between 69 and 152 years. Based on a previously developed master dating chronology using Qilian juniper samples from the eastern Qaidam Basin, the calendar dates of the 16 specimens were determined by the COFECHA program and visual dating procedure. The average inter-series correlation among the dated sample series is 0.696, indicating good quality of cross-dating. The year of the outermost rings is AD 715 for the 7 discs and 4 out of the 9 increment cores. Moreover, the ring-width variations of the samples are consistent with the existing chronologies from the region. The presence of late-wood of AD 715 in the samples indicated that the Reshui-1 Tomb was completed in late AD 715 or early 716, which means that the Reshui-1 Tomb was finished in the Tubo age. This date provides direct evidence for archaeologists to determine the owner's ethnicity and identify of the Reshui-1 Tomb.

  12. Tree-Ring Dating of the Reshui-1 Tomb in Dulan County, Qinghai Province, North-West China.

    Directory of Open Access Journals (Sweden)

    Mingqi Li

    Full Text Available Tuyuhun and Tubo were two important states that thrived in north-western China during AD 311-900 in parallel with the Han Chinese dynasties of Sui and Tang periods. The Reshui Tomb Cluster located in Dulan County of the north-eastern Tibetan Plateau is an important cultural relic of the Tuyuhun-Tubo age. The official excavations of the Reshui tombs were regarded as top events in archaeology in the 1980s and 1990s in China. The Reshui-1 Tomb is the largest one among the tombs in the area. Since its excavation, there have been debates on whether the owner of the tomb belonged to the Tuyuhun or Tubo ethnicity. Therefore, accurately dating the Reshui-1 Tomb has a critical place in studying the Tubo and Tuyuhun histories. We collected 7 discs and 11 increment cores of Qilian juniper (Juniperus przewalskii Kom. from the exposed and fallen beams of the roof of the Reshui-1Tomb. The lengths of the 16 tree-ring records are between 69 and 152 years. Based on a previously developed master dating chronology using Qilian juniper samples from the eastern Qaidam Basin, the calendar dates of the 16 specimens were determined by the COFECHA program and visual dating procedure. The average inter-series correlation among the dated sample series is 0.696, indicating good quality of cross-dating. The year of the outermost rings is AD 715 for the 7 discs and 4 out of the 9 increment cores. Moreover, the ring-width variations of the samples are consistent with the existing chronologies from the region. The presence of late-wood of AD 715 in the samples indicated that the Reshui-1 Tomb was completed in late AD 715 or early 716, which means that the Reshui-1 Tomb was finished in the Tubo age. This date provides direct evidence for archaeologists to determine the owner's ethnicity and identify of the Reshui-1 Tomb.

  13. Isotope signals and anatomical features in tree rings suggest a role for hydraulic strategies in diffuse drought-induced die-back of Pinus nigra.

    Science.gov (United States)

    Petrucco, Laura; Nardini, Andrea; von Arx, Georg; Saurer, Matthias; Cherubini, Paolo

    2017-04-01

    The 2003 and 2012 summer seasons were among the warmest and driest of the last 200 years over southeastern Europe, and in particular in the Karst region (northeastern Italy). Starting from winter-spring 2013, several black pines (Pinus nigra J.F. Arnold) suffered crown die-back. Declining trees occurred nearby individuals with no signs of die-back, raising hypotheses about the occurrence of individual-specific hydraulic strategies underlying different responses to extreme drought. We investigated possible processes driving black pine decline by dendrochronological and wood anatomical measurements, coupled with analysis of tree-ring carbon (δ13C) and oxygen (δ18O) isotopic composition in healthy trees (H) and trees suffering die-back (D). Die-back trees showed higher growth rates than H trees at the beginning of the last century, but suffered important growth reduction following the dry summers in 2003 and 2012. After the 2012 drought, D trees produced tracheids with larger diameter and greater vulnerability to implosion than H ones. Healthy trees had significantly higher wood δ13C than D trees, reflecting higher water-use efficiency for the surviving trees, i.e., less water transpired per unit carbon gain, which could be related to lower stomatal conductance and a more conservative use of water. Relatively high δ18O for D trees indicates that they were strongly dependent on shallow water sources, or that they sustained higher transpiration rates than H trees. Our results suggest that H trees adopted a more conservative water-use strategy under drought stress compared with D trees. We speculate that this diversity might have a genotypic basis, but other possible explanations, like different rooting depth, cannot be ruled out. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Tree-ring-based snowfall record for cold arid western Himalaya, India since A.D. 1460

    Science.gov (United States)

    Yadav, Ram R.; Bhutiyani, Mahendra R.

    2013-07-01

    Understanding snowfall variations in high-elevation cold arid regions of the western Himalaya is important as snowmelt water is the main source of water to meet the scores of socioeconomic needs. The ground-based observational data, though limited to the last two decades, show decreasing snowfall, raising the concern of looming water scarcity in the region. The tree-ring data of Himalayan cedar from a network of six moisture-stressed sites, where snowmelt water is the sole source of soil moisture for tree growth, were used to develop the November-April snow water equivalent (SWE) extending back to A.D. 1460. The reconstruction revealed persistent severe droughts in the 1780s followed by the 1480s and relatively lesser magnitude droughts in the 1540s-1560s, 1740s, and early twentieth century. The pluvial conditions observed in 1948-1958 and 1986-1996 stand out over any other period of such duration. The SWE reconstruction revealed large-scale spatial coherence with the corresponding month's Palmer Drought Severity Index over the western Himalayan region. Significant relationship observed between SWE reconstruction and January-March Chenab River flow revealed its potential utility in understanding water resource availability in the long-term perspective.

  15. 15N in tree rings as a bio-indicator of changing nitrogen cycling in tropical forests: an evaluation at three sites using two sampling methods

    NARCIS (Netherlands)

    Sleen, van der J.P.; Vlam, M.; Groenendijk, P.; Anten, N.P.R.; Bongers, F.; Bunyavejchewin, S.; Hietz, P.; Pons, T.L.; Zuidema, P.

    2015-01-01

    Anthropogenic nitrogen deposition is currently causing a more than twofold increase of reactive nitrogen input over large areas in the tropics. Elevated N-15 abundance (delta N-15) in the growth rings of some tropical trees has been hypothesized to reflect an increased leaching of N-15-depleted

  16. Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO2 assimilation and growth in Douglas-fir

    Science.gov (United States)

    Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible...

  17. Comparison of water-use efficiency estimates based on tree-ring carbon isotopes with simulations of a dynamic vegetation model

    Science.gov (United States)

    Saurer, Matthias; Renato, Spahni; Fortunat, Joos; David, Frank; Kerstin, Treydte; Rolf, Siegwolf

    2015-04-01

    Tree-ring d13C-based estimates of intrinsic water-use efficiency (iWUE, reflecting the ratio of assimilation A to stomatal conductance gs) generally show a strong increase during the industrial period, likely associated with the increase in atmospheric CO2. However, it is not clear, first, if tree-ring d13C-derived iWUE-values indeed reflect actual plant and ecosystem-scale variability in fluxes and, second, what physiological changes were the drivers of the observed iWUE increase, changes in A or gs or both. To address these questions, we used a complex dynamic vegetation model (LPX) that combines process-based vegetation dynamics with land-atmosphere carbon and water exchange. The analysis was conducted for three functional types, representing conifers, oaks, larch, and various sites in Europe, where tree-ring isotope data are available. The increase in iWUE over the 20th century was comparable in LPX-simulations as in tree-ring-estimates, strengthening confidence in these results. Furthermore, the results from the LPX model suggest that the cause of the iWUE increase was reduced stomatal conductance during recent decades rather than increased assimilation. High-frequency variation reflects the influence of climate, like for example the 1976 summer drought, resulting in strongly reduced A and g in the model, particularly for oak.

  18. Spatial and temporal distribution of 14C in cellulose in tree rings in Central and Eastern Canada: comparison with long-term atmospheric and environmental data

    International Nuclear Information System (INIS)

    Kotzer, T.G.; Watson, W.L.

    1999-05-01

    Dendrochronologically characterized tree rings from several different species across Central and Eastern Canada and spanning a time range of several decades have been analysed for their 14 C specific activities using oxygen combustion - direct liquid scintillation counting techniques. Carbon-14 specific activities varied between 218 and 439 Bq·kg -1 (±5 to 10%) and yielded a good correlation with the 14 C measured in long-term records of 14 C-in-air values, although 14 C levels in Canada are slightly higher (10 to 20 per mil). An average pre-bomb 14 C value of 225 Bq·kg -1 was obtained from tree rings between 1910 and 1945 which agrees with the value for NBS oxalic acid standard for 'modern' 14 C at 226 Bq·kg -1 . Present-day levels of 14 C in the tree rings are on the order of 250 Bq·kg -1 , indicating that they, like 14 C0 2 -in-air values, have yet to reach 'pre-nuclear testing' levels. Specific activities of 14 C in tree rings from several sites in Canada show no systematic changes with respect to their distance from CANDU heavy-water nuclear power generating stations, suggesting that these stations have had negligible effects on the atmospheric radiocarbon budget for mid-latitudinal North America. The radiocarbon data from the tree rings indicate that atmospheric 14 C has an atmospheric half-time on the order of approximately 15 years, similar to that from other data sets. (author)

  19. Tree-ring growth patterns and climatic signals along a vertical transect of larch sites in the Simplon and Rhône Valleys (Switzerland)

    Science.gov (United States)

    Riechelmann, Dana F. C.; Esper, Jan

    2017-04-01

    State-of-the-art millennial long temperature reconstructions from the European Alps integrate wood samples of Larix decidua Mill. from the Lötschental and Simplon regions in Switzerland (Büntgen et al., 2005; 2006). Some of the oldest samples that enable the extension of the time-series back into the first millennium AD are obtained from old buildings in Simplon Village, through the precise location of these samples and the elevation of sampling sites remain unknown. We here evaluate the growth characteristics of larch tree-ring width data along a vertical transect in the Simplon and Rhône valleys. 330 trees from nine sites in 985, 1100, 1400, 1575, 1710, 1712, 1900, 2020, and 2150 m asl have been sampled and analysed for their climate signals. The results indicate a stronger temperature signal in the tree-ring width with increasing elevation. The lower the sites the more a drought signal is imprinted in the ring width data. The intermediate site at 1400 m asl does not show any pronounced climate signal. A comparison of growth patterns of living-tree sites with samples from the historical buildings in Simplon Village (Riechelmann et al., 2013) indicates the construction timber to origin from intermediate to higher elevations. We therefore do not expect strong temperature signal from these timbers. References: Büntgen, U., Esper, J., Frank, D.C., Nicolussi, K., Schmidhalter, M., 2005. A 1052-year tree-ring proxy for Alpine summer temperatures. Climate Dynamics 25: 141-153. Büntgen, U., Frank, D.C., Nievergelt, D., Esper J., 2006. Summer temperature variations in the European Alps, A.D. 755-2004. Journal of Climate 19: 5606-5623. Riechelmann, D.F.C., Schmidhalter, M., Büntgen, U., Esper, J., 2013. Extending a high-elevation larch ring width chronology from the Simplon region in the Swiss Alps over the past millenium. TRACE 11:103-108.

  20. Spring-Summer Temperatures Since AD 1780 Reconstructed from Stable Oxygen Isotope Ratios in White Spruce Tree-Rings from the Mackenzie Delta, Northwestern Canada

    Science.gov (United States)

    Porter, Trevor J.; Pisaric, Michael F. J.; Field, Robert D.; Kokelj, Steven V.; Edwards, Thomas W. D.; deMontigny, Peter; Healy, Richard; LeGrande, Allegra N.

    2013-01-01

    High-latitude delta(exp 18)O archives deriving from meteoric water (e.g., tree-rings and ice-cores) can provide valuable information on past temperature variability, but stationarity of temperature signals in these archives depends on the stability of moisture source/trajectory and precipitation seasonality, both of which can be affected by atmospheric circulation changes. A tree-ring delta(exp 18)O record (AD 1780-2003) from the Mackenzie Delta is evaluated as a temperature proxy based on linear regression diagnostics. The primary source of moisture for this region is the North Pacific and, thus, North Pacific atmospheric circulation variability could potentially affect the tree-ring delta(exp 18)O-temperature signal. Over the instrumental period (AD 1892-2003), tree-ring delta(exp 18)O explained 29% of interannual variability in April-July minimum temperatures, and the explained variability increases substantially at lower-frequencies. A split-period calibration/verification analysis found the delta(exp 18)O-temperature relation was time-stable, which supported a temperature reconstruction back to AD 1780. The stability of the delta(exp 18)O-temperature signal indirectly implies the study region is insensitive to North Pacific circulation effects, since North Pacific circulation was not constant over the calibration period. Simulations from the NASA-GISS ModelE isotope-enabled general circulation model confirm that meteoric delta(exp 18)O and precipitation seasonality in the study region are likely insensitive to North Pacific circulation effects, highlighting the paleoclimatic value of tree-ring and possibly other delta(exp 18)O records from this region. Our delta(exp 18)O-based temperature reconstruction is the first of its kind in northwestern North America, and one of few worldwide, and provides a long-term context for evaluating recent climate warming in the Mackenzie Delta region.

  1. Summer drought reconstruction in northeastern Spain inferred from a tree ring latewood network since 1734

    Science.gov (United States)

    Tejedor, E.; Saz, M. A.; Esper, J.; Cuadrat, J. M.; de Luis, M.

    2017-08-01

    Drought recurrence in the Mediterranean is regarded as a fundamental factor for socioeconomic development and the resilience of natural systems in context of global change. However, knowledge of past droughts has been hampered by the absence of high-resolution proxies. We present a drought reconstruction for the northeast of the Iberian Peninsula based on a new dendrochronology network considering the Standardized Evapotranspiration Precipitation Index (SPEI). A total of 774 latewood width series from 387 trees of P. sylvestris and P. uncinata was combined in an interregional chronology. The new chronology, calibrated against gridded climate data, reveals a robust relationship with the SPEI representing drought conditions of July and August. We developed a summer drought reconstruction for the period 1734-2013 representative for the northeastern and central Iberian Peninsula. We identified 16 extremely dry and 17 extremely wet summers and four decadal scale dry and wet periods, including 2003-2013 as the driest episode of the reconstruction.

  2. Climatic response of stable isotope variations in wood cellulose of pine (Pinus sylvestris l.) and their tree-ring width on the Kola Peninsula, north-western Russia

    International Nuclear Information System (INIS)

    Boettger, T.; Hiller, A.; Gehre, M.; Friedrich, M.; Kremenetski, C.

    2002-01-01

    The Kola Peninsula region of northwestern Russia, adjacent to relatively well studied Scandinavian areas, is climatically affected by not only the Gulf Stream and the North Atlantic but also the Eurasian continent. Living and subfossil pine trees from the Khibiny mountains on the Kola Peninsula were analysed for carbon, oxygen and hydrogen isotope composition and for tree-ring width. Comparisons of local meteorological and tree-ring data revealed significant correlations. δ 13 C and δ 18 O values are particularly sensitive to changes in the temperature in July and August and to precipitation in the winter months of the previous year, respectively. On average, 13 C in the cellulose of pine trees between c. 1000 and 1300 AD is enriched by δ values of around 1 per mille compared to the modern trees from this region. This indicates a distinctly warmer summer climate at that time (the Medieval Warm epoch in Europe) than recently observed. The δ 18 O values of wood cellulose and the δ 2 H values of non-exchangeable hydrogen of tree cellulose from both fossil and modern samples cover a wide range between around 22 and 29 per mille and between about -80 and -120 per mille vs. SMOW, respectively. This suggests variations in the seasonal distribution of precipitation at that time, assuming its source has remained the same as in the past. (author)

  3. Exploring Historical Coffee and Climate Relations in Southern Guatemala: An Integration of Tree Ring Analysis and Remote Sensing Data =

    Science.gov (United States)

    Pons, Diego

    This dissertation makes use of a physical geography perspective to examine the relationship between agriculture and climate in Guatemala using dendrochronology. I examined the potential of high-resolution climate proxy data from dendrochronology to help fill in the gaps of past climate information to better understand the natural and anthropogenic variability of precipitation which, in turn, can inform Guatemala's agriculture sector. This research has demonstrated successful cross-dating and climate sensitivity of Abies guatemalensis in the Pacific slope of Guatemala. Based on this, I have produced a 124-year record of mean precipitation from June-July-August. The mean precipitation from June-July-August at this site seems to receive an important influence from the sea surface temperature (SST) in the Pacific Ocean in the form of El Nino-Southern Oscillation (ENSO) in the region 3.4. The analysis on the frequency of the precipitation records suggests that single year droughts dominate the record yet, periods of 9 years below-average rainfall can persist. Likewise, single year pluvial events also dominate the evaluated period. The long-term reconstruction of precipitation allowed to describe past relationships between coffee plantations and pests. For instance, the frequency analysis suggests that 4 or more consecutive periods of above-average precipitation are associated with several coffee pests and subsequently great economical losses due to crop failures, including the last coffee leaf rust crisis. This study also presents a streamflow reconstruction of the Upper Samala River watershed using a tree ring-width chronology derived from the Guatemalan fir (Abies guatemalensis) to reconstruct mean August-September-October streamflow volumes for the period 1889-2013. Our analysis shows that strong statistical correlations are present between tree-ring width measurements and monthly natural streamflow series. The mean August-September-October streamflow variability is

  4. Tree ring-based seven-century drought records for the Western Himalaya, India

    Science.gov (United States)

    Yadav, Ram R.

    2013-05-01

    The paucity of available instrumental climate records in cold and arid regions of the western Himalaya, India, hampers our understanding of the long-term variability of regional droughts, which seriously affect the agrarian economy of the region. Using ring width chronologies of Cedrus deodara and Pinus gerardiana together from a network of moisture-stressed sites, Palmer Drought Severity Index values for October-May back to 1310 A.D. were developed. The twentieth century features dominant decadal-scale pluvial phases (1981-1995, 1952-1968, and 1918-1934) as compared to the severe droughts in the early seventeenth century (1617-1640) as well as late fifteenth to early sixteenth (1491-1526) centuries. The drought anomalies are positively (negatively) associated with central Pacific (Indo-Pacific Warm Pool) sea surface temperature anomalies. However, non-stationarity in such relationships appears to be the major riddle in the predictability of long-term droughts much needed for the sustainable development of the ecologically sensitive region of the Himalayas.

  5. A watershed modeling approach to streamflow reconstruction from tree-ring records

    International Nuclear Information System (INIS)

    Saito, Laurel; Biondi, Franco; Salas, Jose D; Panorska, Anna K; Kozubowski, Tomasz J

    2008-01-01

    Insight into long-term changes of streamflow is critical for addressing implications of global warming for sustainable water management. To date, dendrohydrologists have employed sophisticated regression techniques to extend runoff records, but this empirical approach cannot directly test the influence of watershed factors that alter streamflow independently of climate. We designed a mechanistic watershed model to calculate streamflows at annual timescales using as few inputs as possible. The model was calibrated for upper reaches of the Walker River, which straddles the boundary between the Sierra Nevada of California and the Great Basin of Nevada. Even though the model incorporated simplified relationships between precipitation and other components of the hydrologic cycle, it predicted water year streamflows with correlations of 0.87 when appropriate precipitation values were used

  6. Impact of trees on pollutant dispersion in street canyons: A numerical study of the annual average effects in Antwerp, Belgium.

    Science.gov (United States)

    Vranckx, Stijn; Vos, Peter; Maiheu, Bino; Janssen, Stijn

    2015-11-01

    Effects of vegetation on pollutant dispersion receive increased attention in attempts to reduce air pollutant concentration levels in the urban environment. In this study, we examine the influence of vegetation on the concentrations of traffic pollutants in urban street canyons using numerical simulations with the CFD code OpenFOAM. This CFD approach is validated against literature wind tunnel data of traffic pollutant dispersion in street canyons. The impact of trees is simulated for a variety of vegetation types and the full range of approaching wind directions at 15° interval. All these results are combined using meteo statistics, including effects of seasonal leaf loss, to determine the annual average effect of trees in street canyons. This analysis is performed for two pollutants, elemental carbon (EC) and PM10, using background concentrations and emission strengths for the city of Antwerp, Belgium. The results show that due to the presence of trees the annual average pollutant concentrations increase with about 8% (range of 1% to 13%) for EC and with about 1.4% (range of 0.2 to 2.6%) for PM10. The study indicates that this annual effect is considerably smaller than earlier estimates which are generally based on a specific set of governing conditions (1 wind direction, full leafed trees and peak hour traffic emissions). Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Sunshine duration reconstruction in the southeastern Tibetan Plateau based on tree-ring width and its relationship to volcanic eruptions.

    Science.gov (United States)

    Sun, Changfeng; Liu, Yu; Song, Huiming; Cai, Qiufang; Li, Qiang; Wang, Lu; Mei, Ruochen; Fang, Congxi

    2018-07-01

    Sunshine is as essential as temperature and precipitation for tree growth, but sunshine duration reconstructions based on tree rings have not yet been conducted in China. In this study, we presented a 497-year sunshine duration reconstruction for the southeastern Tibetan Plateau using a width chronology of Abies forrestii from the central Hengduan Mountains. The reconstruction accounted for 53.5% of the variance in the observed sunshine during the period of 1961-2013 based on a stable and reliable linear regression. This reconstructed sunshine duration contained six sunny periods (1630-1656, 1665-1697, 1731-1781, 1793-1836, 1862-1895 and 1910-1992) and seven cloudy periods (1522-1629, 1657-1664, 1698-1730, 1782-1792, 1837-1861, 1896-1909 and 1993-2008) at a low-frequency scale. There was an increasing trend from the 16th century to the late 18th and early 19th centuries and a decreasing trend from the mid-19th to the early 21st centuries. Sunshine displayed inverse patterns to the local Palmer drought severity index on a multidecadal scale, indicating that this region likely experienced droughts under more sunshine conditions. The decrease in sunshine particularly in recent decades was mainly due to increasing atmospheric anthropogenic aerosols. In terms of the interannual variations in sunshine, weak sunshine years matched well with years of major volcanic eruptions. The significant cycles of the 2- to 7-year, 20.0-year and 35.2-year durations as well as the 60.2-year and 78.7-year durations related to the El-Niño Southern Oscillation, the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation suggested that the variation in sunshine duration in the southeastern Tibetan Plateau was possibly affected by large-scale ocean-atmosphere circulations. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Sierra San Pedro Mártir, Baja California, cool-season precipitation reconstructed from earlywood width of Abies concolor tree rings

    Science.gov (United States)

    Meko, D. M.; Touchan, R.; Díaz, J. Villanueva; Griffin, D.; Woodhouse, C. A.; Castro, C. L.; Carillo, C.; Leavitt, S. W.

    2013-12-01

    Tree ring data are analyzed for a multicentury record of drought history in the Sierra San Pedro Mártir (SSPM) of Baja California, Mexico. Climatic variation in the study area is of particular interest because the SSPM is a rich biotic environment at the southern limit of the California floristic province and the southern limit of the planetary jet stream. Future shifts in the jet stream would be expected to have amplified effect on this marginal environment. The study applies linear regression to tree ring indices of earlywood-width of Abies concolor to estimate a 353 year (1658-2010 C.E.) record of cool-season (October-April) precipitation, P, in SSPM. Time-nested regression models account for more than half the variance of grid point P in calibration periods of length 50-65 years. Cross-spectral analysis indicates strong tracking of observed P by the reconstruction over a broad range of frequencies. Robustness of the reconstruction is supported by synchrony of reconstructed P with tree ring variations in other tree species from SSPM. The reconstruction emphasizes the severity of the 1950s drought in a long-term context and the single-year intensity of droughts in the last decade: 2007 stands out as the driest reconstructed year, with a high percentage of missing rings in A. concolor. The reconstruction identifies the early twentieth century pluvial as the wettest epoch in the last 353 years in the SSPM. High-elevation tree species in SSPM may be especially well-suited to sensing snowpack-related moisture variations associated with a southerly branched jet stream and the types of weather systems active in the pluvial.

  9. Treating pre-instrumental data as "missing" data: using a tree-ring-based paleoclimate record and imputations to reconstruct streamflow in the Missouri River Basin

    Science.gov (United States)

    Ho, M. W.; Lall, U.; Cook, E. R.

    2015-12-01

    Advances in paleoclimatology in the past few decades have provided opportunities to expand the temporal perspective of the hydrological and climatological variability across the world. The North American region is particularly fortunate in this respect where a relatively dense network of high resolution paleoclimate proxy records have been assembled. One such network is the annually-resolved Living Blended Drought Atlas (LBDA): a paleoclimate reconstruction of the Palmer Drought Severity Index (PDSI) that covers North America on a 0.5° × 0.5° grid based on tree-ring chronologies. However, the use of the LBDA to assess North American streamflow variability requires a model by which streamflow may be reconstructed. Paleoclimate reconstructions have typically used models that first seek to quantify the relationship between the paleoclimate variable and the environmental variable of interest before extrapolating the relationship back in time. In contrast, the pre-instrumental streamflow is here considered as "missing" data. A method of imputing the "missing" streamflow data, prior to the instrumental record, is applied through multiple imputation using chained equations for streamflow in the Missouri River Basin. In this method, the distribution of the instrumental streamflow and LBDA is used to estimate sets of plausible values for the "missing" streamflow data resulting in a ~600 year-long streamflow reconstruction. Past research into external climate forcings, oceanic-atmospheric variability and its teleconnections, and assessments of rare multi-centennial instrumental records demonstrate that large temporal oscillations in hydrological conditions are unlikely to be captured in most instrumental records. The reconstruction of multi-centennial records of streamflow will enable comprehensive assessments of current and future water resource infrastructure and operations under the existing scope of natural climate variability.

  10. Annual increments of juniper dwarf shrubs above the tree line on the central Tibetan Plateau: a useful climatic proxy

    Science.gov (United States)

    Liang, Eryuan; Lu, Xiaoming; Ren, Ping; Li, Xiaoxia; Zhu, Liping; Eckstein, Dieter

    2012-01-01

    Background and Aims Dendroclimatology is playing an important role in understanding past climatic changes on the Tibetan Plateau. Forests, however, are mainly confined to the eastern Tibetan Plateau. On the central Tibetan Plateau, in contrast, shrubs and dwarf shrubs need to be studied instead of trees as a source of climate information. The objectives of this study were to check the dendrochronological potential of the dwarf shrub Wilson juniper (Juniperus pingii var. wilsonii) growing from 4740 to 4780 m a.s.l. and to identify the climatic factors controlling its radial growth. Methods Forty-three discs from 33 stems of Wilson juniper were sampled near the north-eastern shore of the Nam Co (Heavenly Lake). Cross-dating was performed along two directions of each stem, avoiding the compression-wood side as far as possible. A ring-width chronology was developed after a negative exponential function or a straight line of any slope had been fit to the raw measurements. Then, correlations were calculated between the standard ring-width chronology and monthly climate data recorded by a weather station around 100 km away. Key Results Our study has shown high dendrochronological potential of Wilson juniper, based on its longevity (one individual was 324 years old), well-defined growth rings, reliable cross-dating between individuals and distinct climatic signals reflected by the ring-width variability. Unlike dwarf shrubs in the circum-arctic tundra ecosystem which positively responded to above-average temperature in the growing season, moisture turned out to be growth limiting for Wilson juniper, particularly the loss of moisture caused by high maximum temperatures in May–June. Conclusions Because of the wide distribution of shrub and dwarf shrub species on the central Tibetan Plateau, an exciting prospect was opened up to extend the presently existing tree-ring networks far up into one of the largest tundra regions of the world. PMID:22210848

  11. Annual increments of juniper dwarf shrubs above the tree line on the central Tibetan Plateau: a useful climatic proxy.

    Science.gov (United States)

    Liang, Eryuan; Lu, Xiaoming; Ren, Ping; Li, Xiaoxia; Zhu, Liping; Eckstein, Dieter

    2012-03-01

    Dendroclimatology is playing an important role in understanding past climatic changes on the Tibetan Plateau. Forests, however, are mainly confined to the eastern Tibetan Plateau. On the central Tibetan Plateau, in contrast, shrubs and dwarf shrubs need to be studied instead of trees as a source of climate information. The objectives of this study were to check the dendrochronological potential of the dwarf shrub Wilson juniper (Juniperus pingii var. wilsonii) growing from 4740 to 4780 m a.s.l. and to identify the climatic factors controlling its radial growth. Forty-three discs from 33 stems of Wilson juniper were sampled near the north-eastern shore of the Nam Co (Heavenly Lake). Cross-dating was performed along two directions of each stem, avoiding the compression-wood side as far as possible. A ring-width chronology was developed after a negative exponential function or a straight line of any slope had been fit to the raw measurements. Then, correlations were calculated between the standard ring-width chronology and monthly climate data recorded by a weather station around 100 km away. Our study has shown high dendrochronological potential of Wilson juniper, based on its longevity (one individual was 324 years old), well-defined growth rings, reliable cross-dating between individuals and distinct climatic signals reflected by the ring-width variability. Unlike dwarf shrubs in the circum-arctic tundra ecosystem which positively responded to above-average temperature in the growing season, moisture turned out to be growth limiting for Wilson juniper, particularly the loss of moisture caused by high maximum temperatures in May-June. Because of the wide distribution of shrub and dwarf shrub species on the central Tibetan Plateau, an exciting prospect was opened up to extend the presently existing tree-ring networks far up into one of the largest tundra regions of the world.

  12. Water availability reconstructions using tree-rings in the Valdivian rainforest ecoregion, Chile

    International Nuclear Information System (INIS)

    Urrutia, Rocio; Pena, M P; Christie, Duncan A; Lara, Antonio

    2010-01-01

    Water availability can be considered as one of the main restrictions for future development in South-Central Chile, due to the reported decreasing trends in precipitation in the last decades and the increasing demand for this resource. This issue makes the study of past water availability fundamental for the understanding of present and future variations. This paper presents a comparison of two water availability reconstructions within the Valdivian rainforest ecoregion (35 0 -48 0 S), one corresponding to a precipitation (37 0 -39.5 0 S) and the other to a streamflow reconstruction (41 0 S). This study shows that there are fundamental differences between them especially in the long term variability. However, there are also coincidences, mainly at higher frequency variations, such as at a bidecadal, decadal and annual scale. Another important finding is that these reconstructions show significant correlations with different climatic forcings in this area. The northern reconstruction presents a significant relationship with ENSO (El Nino Southern Oscillation), while the southern does the same with the AAO (Antarctic Oscillation Index).

  13. Trees

    Science.gov (United States)

    Al-Khaja, Nawal

    2007-01-01

    This is a thematic lesson plan for young learners about palm trees and the importance of taking care of them. The two part lesson teaches listening, reading and speaking skills. The lesson includes parts of a tree; the modal auxiliary, can; dialogues and a role play activity.

  14. Relating ring width of Mediterranean evergreen species to seasonal and annual variations of precipitation and temperature

    NARCIS (Netherlands)

    Nijland, W.; Jansma, E.; Addink, E.A.; Domínguez Delmás, M.; Jong, S.M. de

    2011-01-01

    Plant growth in Mediterranean landscapes is limited by the typical summer-dry climate. Forests in these areas are only marginally productive and may be quite susceptible to modern climate change. To improve our understanding of forest sensitivity to annual and seasonal climatic variability, we

  15. Synchronous multi-decadal climate variability of the whole Pacific areas revealed in tree rings since 1567

    Science.gov (United States)

    Fang, Keyan; Cook, Edward; Guo, Zhengtang; Chen, Deliang; Ou, Tinghai; Zhao, Yan

    2018-02-01

    Oceanic and atmospheric patterns play a crucial role in modulating climate variability from interannual to multi-decadal timescales by causing large-scale co-varying climate changes. The brevity of the existing instrumental records hinders the ability to recognize climate patterns before the industrial era, which can be alleviated using proxies. Unfortunately, proxy based reconstructions of oceanic and atmospheric modes of the past millennia often have modest agreements with each other before the instrumental period, raising questions about the robustness of the reconstructions. To ensure the stability of climate signals in proxy data through time, we first identified tree-ring datasets from distant regions containing coherent variations in Asia and North America, and then interpreted their climate information. We found that the multi-decadal covarying climate patterns of the middle and high latitudinal regions around the northern Pacific Ocean agreed quite well with the climate reconstructions of the tropical and southern Pacific areas. This indicates a synchronous variability at the multi-decadal timescale of the past 430 years for the entire Pacific Ocean. This pattern is closely linked to the dominant mode of the Pacific sea surface temperature (SST) after removing the warming trend. This Pacific multi-decadal SST variability resembles the Interdecadal Pacific Oscillation.

  16. Effects of elevated CO2 concentration on growth, annual ring structure and photosynthesis in Larix kaempferi seedlings

    International Nuclear Information System (INIS)

    Yazaki, K.; Ishida, S.; Kawagishi, T.; Fukatsu, E.; Funada, R.; Maruyama, Y.; Kitao, M.; Tobita, H.; Koike, T.

    2004-01-01

    The effects of elevated carbon dioxide concentration and two nutrient regimes on stem growth rate, annual ring structure and temporal variations in photosynthetic characteristics of seedlings of Japanese larch were evaluated. When compared with ambient carbon dioxide, elevated carbon dioxide reduced stem height and increased stem basal diameter, but had no significant effect on ring width or the number of tracheids per radial file. No obvious difference was observed in cell wall thickness or the relative area of cell wall between seedlings grown in ambient or elevated carbon dioxide. Net assimilation rate increased in the presence of elevated carbon dioxide, however, the increase in whole-crown photosynthetic rate was minimal due to the smaller needle area and acclimation of the photosynthetic characteristics of the needles to the growth in carbon dioxide concentration. Conclusion: elevated carbon dioxide concentration did not appear to significantly affect the capacity of stems of Japanese larch seedlings for carbon fixation for use in cell wall synthesis, although there was evidence of change in the temporal pattern of stem growth and stem thickening. 52 refs., 3 tabs., 4 figs

  17. Evidence of 11-year solar cycles in tree rings from 1010 to 1110 AD – Progress on high precision AMS measurements

    International Nuclear Information System (INIS)

    Güttler, D.; Wacker, L.; Kromer, B.; Friedrich, M.; Synal, H.-A.

    2013-01-01

    Oak tree rings from Southern Germany covering the AD 1010–1110 years have been analyzed for radiocarbon with accelerator mass spectrometry (AMS) at the laboratory at ETH Zurich. High-precision measurements with a precision down to 12 years radiocarbon age and a time resolution of 2 years aimed to identify modulations of the 14 C concentration in tree ring samples caused by the 11 years solar cycles, a feature that so far is not visible in the IntCal calibration curve. Our results are in good agreement with the current calibration curve IntCal09. However, we observed an offset in radiocarbon age of 25–40 years towards older values. An evaluation of our sample preparation, that included variations of e.g.: chemicals, test glasses and processing steps did not explain this offset. The numerous measurements using the AMS-MICADAS system validated its suitability for high precision measurements with high repeatability.

  18. Lengths of Schwabe cycles in the seventh and eighth centuries indicated by precise measurement of carbon-14 content in tree rings

    Science.gov (United States)

    Miyake, Fusa; Masuda, Kimiaki; Nakamura, Toshio

    2013-12-01

    (14C) is produced in the atmosphere by galactic cosmic rays, which are modulated by solar magnetic activity. Its content in tree rings is retained and provides a record of past cosmic ray intensity and solar activity. We have measured, with 2 year resolution, the 14C content in Japanese cedar tree rings for the period A.D. 600 to 760, which includes a small grand solar minimum in the seventh to eighth centuries. Periodicity analysis of the 14C data shows that there is a component in the frequency band of the Schwabe cycle, with a period of 12-13 years continuing throughout the minimum. This is the fourth case in which an increase in the length of the Schwabe cycle has been observed in a grand solar minimum, after the Maunder Minimum, the Spörer Minimum, and the Fourth Century B.C. Minimum.

  19. Tree-ring footprints of drought variability in last ˜300 years over Kumaun Himalaya, India and its relationship with crop productivity

    Science.gov (United States)

    Yadav, Ram R.; Misra, Krishna G.; Yadava, Akhilesh K.; Kotlia, Bahadur S.; Misra, Sandhya

    2015-06-01

    We reconstructed Standardized Precipitation Index (SPI), a metric of drought, using tree-ring width chronologies of Himalayan cedar (Cedrus deodara (Roxb.) G. Don) prepared from two ecologically homogeneous settings in the Kumaun Himalaya, India. The reconstruction employing first principal component of the two site chronologies in linear regression model helped in extending 7-month SPI of May (SPI7-May) back to 1720 CE. The calibration model capturing 60% of variance in the observed SPI series (1902-1967) is the strongest so far from the Indian region. On achieving such a robust tree-ring calibration we are of the opinion that SPI should provide a better option to develop long-term drought records for the data scarce Himalayan region. The SPI reconstruction revealed high year-to-year variability with 1816 (SPI -1.92) and 1737 (SPI +2.33) the driest and the wettest years respectively. The five year mean of reconstructed SPI revealed multiyear droughts in 1920-1924, 1782-1786, 1812-1816, 1744-1748, 1964-1968 and pluvial phases in 1911-1915, 1723-1727, 1788-1792, 1758-1762 and 1733-1737. The SPI7-May was found to be significantly correlated with wheat-barley productivity data of Almora in Kumaun, close to our tree ring sites (r = 0.60, two-tailed p cedar trees are in active vegetation phase of seasonal growth in Almora region. We observed strong and significant correlation in SPI7-May and SPI7-April (r = 0.75, two-tailed p = 0.0001) underpinning that the tree-ring derived SPI7-May could also be taken as a proxy of wheat-barley production in Almora region. This observation also stands for the past as we noted that most of the droughts recorded in our reconstruction (SPI tree rings should serve as an important base line data to quantify the impact of droughts on forest as well as rabi crop productivity in hilly terrains of the Kumaun Himalaya in long-term perspective.

  20. Biomonitoring of environmental pollution using growth tree rings of Tipuana tipu: Quantification by synchrotron radiation total reflection X-ray fluorescence

    Science.gov (United States)

    Geraldo, S. M.; Canteras, F. B.; Moreira, S.

    2014-02-01

    Currently, many studies use the bioindicators to qualitatively and/or quantitatively measure pollution. The analyses of tree growth rings represent one such bioindicator as changes in the environment are often recorded as impressions in the wood. The main objective of the present study is to examine the growth rings of Tipuana tipu - a member of the Leguminosae family that is native to Argentina and Bolivia and was introduced in Brazil as an ornamental plant - for potentially toxic elements. T. tipu is one of the most common trees in the urban landscape of Sao Paulo city and would provide an accurate reflection of environment changes. Tree ring samples previously dated using Synchrotron Radiation Total Reflection X-ray Fluorescence were collected from strategic locations in Sao Paulo. These locations include Piracicaba (SP) that has little access and small flow traffic and the campus of the University of São Paulo. Some trace elements present concentrations higher than considered as normal in some periods. In São Paulo city, samples collected from the campus of University of São Paulo (Butantã), showed the highest toxicity, with concentrations above the tolerable limit for the elements: Cr, Cu, and Pb. For the samples collected in Piracicaba city, one sample presented highest concentrations for the majority of the elements when compared to the other four samples collected at the same place, exceeding the toxicity limits for: Cr, Ni, Cu, and Pb.

  1. Dry seasons identified in oak tree-ring chronology in the Czech Lands over the last millennium

    Science.gov (United States)

    Dobrovolny, Petr; Brazdil, Rudolf; Büntgen, Ulf; Rybnicek, Michal; Kolar, Tomas; Reznickova, Ladislava; Valasek, Hubert; Kotyza, Oldrich

    2015-04-01

    There is growing evidence on amplification of hydrological regimes as a consequence of rising temperatures, increase in evaporation and changes in circulation patterns. These processes may be responsible for higher probability of hydroclimatic extremes occurrence in regional scale. Extreme events such as floods or droughts are rare from their definition and for better understanding of possible changes in the frequency and intensity of their occurrence, long-term proxy archives may be analysed. Recently several tree ring width chronologies were compiled from hardwood species occurring in lowland positions and their analysis proved that they are moisture-sensitive and suitable for hydroclimate reconstructions. Here, we introduce a new oak (Quercus sp) ring width (RW) dataset for the Czech Republic and the last 1250 years. We explain the process of oak chronology standardization that was based on several only slightly different de-trending techniques and subsequent chronology development steps. We hypothesize that the most severe RW increment reductions (negative extremes) reflect extremely dry spring-summer conditions. Negative extremes were assigned for years in which transformed oak RWs were lower than the minus 1.5 standard deviation. To verify our hypothesis, we compare typical climatic conditions in negative extreme years with climatology of the reference period 1961-1990. Comparison was done for various instrumental measurements (1805-2012), existing proxy reconstructions (1500-1804) and also for documentary evidence from historical archives (before 1500). We found that years of negative extremes are characterized with distinctly above average spring (MAM) and summer (JJA) air temperatures and below average precipitation amounts. Typical sea level pressure spatial distribution in those years shows positive pressure anomaly over British Isles and Northern Sea, the pattern that synoptically corresponds to blocking anticyclone bringing to Central Europe warm air

  2. Regional and Large-Scale Climate Influences on Tree-Ring Reconstructed Null Zone Position in San Francisco Bay

    Science.gov (United States)

    Stahle, D.; Griffin, D.; Cleaveland, M.; Fye, F.; Meko, D.; Cayan, D.; Dettinger, M.; Redmond, K.

    2007-05-01

    A new network of 36 moisture sensitive tree-ring chronologies has been developed in and near the drainage basins of the Sacramento and San Joaquin Rivers. The network is based entirely on blue oak (Quercus douglasii), which is a California endemic found from the lower forest border up into the mixed conifer zone in the Coast Ranges, Sierra Nevada, and Cascades. These blue oak tree-ring chronologies are highly correlated with winter-spring precipitation totals, Sacramento and San Joaquin streamflow, and with seasonal variations in salinity and null zone position in San Francisco Bay. Null zone is the non-tidal bottom water location where density-driven salinity and river-driven freshwater currents balance (zero flow). It is the area of highest turbidity, water residence time, sediment accumulation, and net primary productivity in the estuary. Null zone position is measured by the distance from the Golden Gate of the 2 per mil bottom water isohaline and is primarily controlled by discharge from the Sacramento and San Joaquin Rivers (and ultimately by winter-spring precipitation). The location of the null zone is an estuarine habitat indicator, a policy variable used for ecosystem management, and can have a major impact on biological resources in the San Francisco estuary. Precipitation-sensitive blue oak chronologies can be used to estimate null zone position based on the strong biogeophysical interaction among terrestrial, aquatic, and estuarine ecosystems, orchestrated by precipitation. The null zone reconstruction is 626-years long and provides a unique long term perspective on the interannual to decadal variability of this important estuarine habitat indicator. Consecutive two-year droughts (or longer) allow the null zone to shrink into the confined upper reaches of Suisun Bay, causing a dramatic reduction in phytoplankton production and favoring colonization of the estuary by marine biota. The reconstruction indicates an approximate 10 year recurrence interval

  3. Tree-ring-based reconstruction of precipitation in the Bighorn Basin, Wyoming, since 1260 A.D

    Science.gov (United States)

    Gray, S.T.; Fastie, C.L.; Jackson, S.T.; Betancourt, J.L.

    2004-01-01

    Cores and cross sections from 79 Douglas fir (Pseudotsuga menziesii) and limber pine (Pinus flexilis) trees at four sites in the Bighorn Basin of north-central Wyoming and south-central Montana were used to develop a proxy for annual (June-June) precipitation spanning 1260-1998 A.D. The reconstruction exhibits considerable nonstationarity, and the instrumental era (post-1900) in particular fails to capture the full range of precipitation variability experienced in the past ???750 years. Both single-year and decadal-scale dry events were more severe before 1900. Dry spells in the late thirteenth and sixteenth centuries surpass both magnitude and duration of any droughts in the Bighorn Basin after 1900. Precipitation variability appears to shift to a higher-frequency mode after 1750, with 15-20-yr droughts becoming rare. Comparisons between instrumental and reconstructed values of precipitation and indices of Pacific basin variability reveal that precipitation in the Bighorn Basin generally responds to Pacific forcing in a manner similar to that of the southwestern United States (drier during La Nin??a events), but high country precipitation in areas surrounding the basin displays the opposite response (drier during El Nin??o events). ?? 2004 American Meteorological Society.

  4. A 323-year long reconstruction of drought for SW Romania based on black pine (Pinus Nigra) tree-ring widths.

    Science.gov (United States)

    Levanič, Tom; Popa, Ionel; Poljanšek, Simon; Nechita, Constantin

    2013-09-01

    Increase in temperature and decrease in precipitation pose a major future challenge for sustainable ecosystem management in Romania. To understand ecosystem response and the wider social consequences of environmental change, we constructed a 396-year long (1615-2010) drought sensitive tree-ring width chronology (TRW) of Pinus nigra var. banatica (Georg. et Ion.) growing on steep slopes and shallow organic soil. We established a statistical relationship between TRW and two meteorological parameters-monthly sum of precipitation (PP) and standardised precipitation index (SPI). PP and SPI correlate significantly with TRW (r = 0.54 and 0.58) and are stable in time. Rigorous statistical tests, which measure the accuracy and prediction ability of the model, were all significant. SPI was eventually reconstructed back to 1688, with extreme dry and wet years identified using the percentile method. By means of reconstruction, we identified two so far unknown extremely dry years in Romania--1725 and 1782. Those 2 years are almost as dry as 1946, which was known as the "year of great famine." Since no historical documents for these 2 years were available in local archives, we compared the results with those from neighbouring countries and discovered that both years were extremely dry in the wider region (Slovakia, Hungary, Anatolia, Syria, and Turkey). While the 1800-1900 period was relatively mild, with only two moderately extreme years as far as weather is concerned, the 1900-2009 period was highly salient owing to the very high number of wet and dry extremes--five extremely wet and three extremely dry events (one of them in 1946) were identified.

  5. A Tree-Ring Reconstruction of the Salinity Gradient in the Northern Estuary of San Francisco Bay

    Directory of Open Access Journals (Sweden)

    David W. Stahle

    2011-04-01

    Full Text Available Blue oak tree-ring chronologies correlate highly with winter–spring precipitation totals over California, with Sacramento and San Joaquin river stream flow, and with seasonal variations in the salinity gradient in San Francisco Bay. The convergence of fresh and saline currents can influence turbidity, sediment accumulation, and biological productivity in the estuary. Three selected blue oak chronologies were used to develop a 625-year-long reconstruction of the seasonal salinity gradient, or low salinity zone (LSZ, which provides a unique perspective on the interannual-to-decadal variability of this important estuarine habitat indicator. The reconstruction was calibrated with instrumental LSZ data for the winter–spring season, and explains 73% of the variance in the February–June position of the LSZ from 1956 to 2003. Because this calibration period post-dates the sweeping changes that have occurred to land cover, channel morphology, and natural streamflow regimes in California, the reconstruction provides an idealized estimate for how the LSZ might have fluctuated under the seasonal precipitation variations of the past 625 years, given the modern geometry and bathymetry of the estuary and land cover across the drainage basin. The February–June season integrates precipitation and runoff variability during the cool season, and does not extend into the late-summer dry season when LSZ extremes can negatively affect Sacramento–San Joaquin Delta (Delta agriculture and some aquatic organisms. However, there is such strong inter-seasonal persistence in the instrumental LSZ data that precipitation totals during the cool season can strongly pre-condition LSZ position in late summer. The 625-year-long reconstruction indicates strong interannual and decadal variability, the frequent recurrence of consecutive 2-year LSZ maxima and minima, large-scale ocean atmospheric forcing, and an interesting asymmetrical influence of warm El Ni

  6. Distribution of radiocesium and stable elements within a pine tree

    International Nuclear Information System (INIS)

    Yoshida, S.; Watanabe, M.; Suzuki, A.

    2011-01-01

    Distributions of 137 Cs and stable elements in different parts of a pine tree collected in Chernobyl-contaminated area in Belarus were determined. Samples include annual tree rings of wood, branches and needles with different ages. The concentrations of 137 Cs and stable Cs in annual tree rings were the highest in cambium and decreased sharply towards inside. The youngest needles and branches contained higher 137 Cs and stable Cs than older ones. The concentration of 137 Cs being highest in growing parts suggests the highest radiation dose to the radiation-sensitive parts of tree. Distribution patterns of stable elements in pine tree differ among the elements. Distributions similar to those of Cs were observed for K and Rb, suggesting that alkaline metals tend to be translocated to young growing parts of pine tree. A similar distribution was also observed for phosphorus. Distributions of alkaline earth metals and several heavy metals were different from those of alkaline metals. (authors)

  7. Annual Growth Bands in Hymenaea courbaril

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, J A; Guilderson, T P; Colinvaux, P A

    2004-02-09

    One significant source of annual temperature and precipitation data arises from the regular annual secondary growth rings of trees. Several tropical tree species are observed to form regular growth bands that may or may not form annually. Such growth was observed in one stem disk of the tropical legume Hymenaea courbaril near the area of David, Panama. In comparison to annual reference {Delta}{sup 14}C values from wood and air, the {Delta}{sup 14}C values from the secondary growth rings formed by H. courbaril were determined to be annual in nature in this one stem disk specimen. During this study, H. courbaril was also observed to translocate recently produced photosynthate into older growth rings as sapwood is converted to heartwood. This process alters the overall {Delta}{sup 14}C values of these transitional growth rings as cellulose with a higher {Delta}{sup 14}C content is translocated into growth rings with a relatively lower {Delta}{sup 14}C content. Once the annual nature of these growth rings is established, further stable isotope analyses on H. courbaril material in other studies may help to complete gaps in the understanding of short and of long term global climate patterns.

  8. Tree ring δ18O reveals no long-term change of atmospheric water demand since 1800 in the northern Great Hinggan Mountains, China

    Science.gov (United States)

    Liu, Xiaohong; Zhang, Xuanwen; Zhao, Liangju; Xu, Guobao; Wang, Lixin; Sun, Weizhen; Zhang, Qiuliang; Wang, Wenzhi; Zeng, Xiaomin; Wu, Guoju

    2017-07-01

    Global warming will significantly increase transpirational water demand, which could dramatically affect plant physiology and carbon and water budgets. Tree ring δ18O is a potential index of the leaf-to-air vapor-pressure deficit (VPD) and therefore has great potential for long-term climatic reconstruction. Here we developed δ18O chronologies of two dominant native trees, Dahurian larch (Larix gmelinii Rupr.) and Mongolian pine (Pinus sylvestris var. mongolica), from a permafrost region in the Great Hinggan Mountains of northeastern China. We found that the July-August VPD and relative humidity were the dominant factors that controlled tree ring δ18O in the study region, indicating strong regulation of stomatal conductance. Based on the larch and pine tree ring δ18O chronologies, we developed a reliable summer (July-August) VPD reconstruction since 1800. Warming growing season temperatures increase transpiration and enrich cellulose 18O, but precipitation seemed to be the most important influence on VPD changes in this cold region. Periods with stronger transpirational demand occurred around the 1850s, from 1914 to 1925, and from 2005 to 2010. However, we found no overall long-term increasing or decreasing trends for VPD since 1800, suggesting that despite the increasing temperatures and thawing permafrost throughout the region, forest transpirational demand has not increased significantly during the past two centuries. Under current climatic conditions, VPD did not limit growth of larch and pine, even during extremely drought years. Our findings will support more realistic evaluations and reliable predictions of the potential influences of ongoing climatic change on carbon and water cycles and on forest dynamics in permafrost regions.

  9. Evaluation of Climate Change in northeastern China by means of d13C in tree-rings in the Great Xiang'An mountains region

    Science.gov (United States)

    Zhang, Qiqin; Lopez Caceres, Maximo Larry; Sugimoto, Atsuko; Wang, Xiaochun; Liu, Binhui

    2017-04-01

    The northeastern forest region of China represents one of the southern boundary of the Asian boreal forest and also represents the boundary between humid- semi humid area and arid- semi arid area of China. These forests are mainly dominated by larch (Larix gmelinii) stands with small areas covered by birch and pine forests. Increases in air temperature and precipitation caused by climate change are expected to have a great effect on forest ecosystems boundaries. Accordingly, from 1963-2006, air temperature has increased 1.5℃ in this region. Tree-ring chronologies are commonly used as indicator of climate changes and in recent decades the combination with carbon stable isotopes has shown a higher resolution in the results. Since this combine technique has not been used in northeastern China, we applied this combined technique to reconstruct the climate in the Great Xing'an mountains of northeastern China. Preliminary results showed that tree growth has increased in the middle and southernmost site in the last century while in the northernmost site it decreased for the same period which is in agreement with the mean air temperature increase from south to north in this region under negligible changes in precipitation regime. In contrast, tree-ring δ13C shows a gradual but steady increase along the three sites selected for our study, however the highest being observed in the middle site which experience the largest increased in air temperature in the last decade. This appears to indicate that increases in air temperature produced a stress in the stomatal conductance that so far has translated into tree ring growth decline.

  10. Medieval climate anomaly and little ice age as recorded in speleothem and tree-ring data from the Middle Atlas in Morocco

    Science.gov (United States)

    Wassenburg, J. A.; Immenhauser, A.; Richter, D. K.; Fietzke, J.; Scholz, D.; Jochum, K. P.; Riechelmann, D. F. C.; Schneider, L.; Esper, J.

    2012-04-01

    Progress has recently been made in assessing the spatial extend and timing of the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) on hemispheric and global scales (Graham et al. 2011). Uncertainties still exist, however, since the transition from the MCA into the LIA seems to be diachronous, and in many cases, reconstructions are based on single climate archives (e.g., speleothems, tree-rings, or pollen data). In Morocco, cedar trees from the Middle and High Atlas have been used to reconstruct the Palmer Drought Severity Index (PDSI) back to 1049 AD (Esper et al., 2007), a metric integrating the evaporation-precipitation balance and soil properties. According to Graham et al. (2011), the MCA/LIA transition recorded in Moroccan tree rings occurred rather late (around 1400 AD) in comparison to the reconstructed winter temperature in the European Alps (e.g., Mangini et al., 2005), which show substantial changes about 50 years earlier. Here we compare precisely dated speleothem δ13C and trace element records from the Middle Atlas with an updated version of the tree-ring based PDSI reconstruction from Esper et al. (2007). Both stalagmite δ13C and strontium records support the prevalence of exceptionally dry conditions during the MCA and relatively wet conditions during the LIA. These changes have formerly been suggested to be related to persistent positive and negative phases of the North Atlantic Oscillation (Trouet et al., 2009). The speleothem based reconstruction extends back to 700 AD and, thus, provides insight on the precise timing of the driest period during the MCA in the Moroccan Middle Atlas.

  11. Tree ring proxies show physiological responses of eastern red cedar to increased CO2 and SO4 concentrations over the 20th century

    Science.gov (United States)

    Thomas, R. B.; Spal, S.; Maxwell, S.; Nippert, J. B.

    2011-12-01

    We examined the relationships between tree growth during the past century and the ratio of internal carbon dioxide concentration to atmospheric CO2 concentration (ci/ca) and instantaneous water-use efficiency (iWUE) by analyzing δ13C in tree rings of Juniperus virginiana growing on a limestone outcrop in West Virginia, US. Tree rings from years 1909 to 2008 from five Juniperus virginiana trees that ranged from 116 years to over 300 years in age were measured for basal area growth and used for isotopic analysis. Instantaneous WUE increased from approximately 75 to 112μmol mmol-1 over the past century, representing a 49% increase. In addition, we found a positive relationship between iWUE and the basal area increase over this time period, suggesting the increase in WUE translated into greater growth of the Juniperus trees. Typically, we might expect that increased growth of these trees reflects increased photosynthetic rates and decreased stomatal conductance rates resulting from increased atmospheric CO2 concentrations. However, this area of the central Appalachian Mountains has historically received some of the highest rates of acid deposition in the nation resulting from being downwind from an abundance of coal-fired power plants in the Ohio River valley. Our results show that ci/ca declined 14% between 1909 and 1980, but increased 9.6% between 1980 and 2009. We hypothesize that the directional change in ci/ca that occurred around 1980 was due to a reduction in sulfur emissions imposed by the Clean Air Act, environmental legislation enacted in 1970 and amended in 1990. Sulfur deposition measured by the National Atmospheric Deposition Program (NADP) in West Virginia near our Juniperus site shows a 53% decline between 1979 and 2009 and these NADP data show a highly significant negative correlation with ci/ca of Juniperus over this time period. Previously, experimental studies have shown that acidic sulfur mist leaches calcium from leaves causing a reduction in

  12. Tree Rings Show Recent High Summer-Autumn Precipitation in Northwest Australia Is Unprecedented within the Last Two Centuries.

    Directory of Open Access Journals (Sweden)

    Alison J O'Donnell

    Full Text Available An understanding of past hydroclimatic variability is critical to resolving the significance of recent recorded trends in Australian precipitation and informing climate models. Our aim was to reconstruct past hydroclimatic variability in semi-arid northwest Australia to provide a longer context within which to examine a recent period of unusually high summer-autumn precipitation. We developed a 210-year ring-width chronology from Callitris columellaris, which was highly correlated with summer-autumn (Dec-May precipitation (r = 0.81; 1910-2011; p < 0.0001 and autumn (Mar-May self-calibrating Palmer drought severity index (scPDSI, r = 0.73; 1910-2011; p < 0.0001 across semi-arid northwest Australia. A linear regression model was used to reconstruct precipitation and explained 66% of the variance in observed summer-autumn precipitation. Our reconstruction reveals inter-annual to multi-decadal scale variation in hydroclimate of the region during the last 210 years, typically showing periods of below average precipitation extending from one to three decades and periods of above average precipitation, which were often less than a decade. Our results demonstrate that the last two decades (1995-2012 have been unusually wet (average summer-autumn precipitation of 310 mm compared to the previous two centuries (average summer-autumn precipitation of 229 mm, coinciding with both an anomalously high frequency and intensity of tropical cyclones in northwest Australia and the dominance of the positive phase of the Southern Annular Mode.

  13. Tree Rings Show Recent High Summer-Autumn Precipitation in Northwest Australia Is Unprecedented within the Last Two Centuries

    Science.gov (United States)

    O'Donnell, Alison J.; Cook, Edward R.; Palmer, Jonathan G.; Turney, Chris S. M.; Page, Gerald F. M.; Grierson, Pauline F.

    2015-01-01

    An understanding of past hydroclimatic variability is critical to resolving the significance of recent recorded trends in Australian precipitation and informing climate models. Our aim was to reconstruct past hydroclimatic variability in semi-arid northwest Australia to provide a longer context within which to examine a recent period of unusually high summer-autumn precipitation. We developed a 210-year ring-width chronology from Callitris columellaris, which was highly correlated with summer-autumn (Dec–May) precipitation (r = 0.81; 1910–2011; p < 0.0001) and autumn (Mar–May) self-calibrating Palmer drought severity index (scPDSI, r = 0.73; 1910–2011; p < 0.0001) across semi-arid northwest Australia. A linear regression model was used to reconstruct precipitation and explained 66% of the variance in observed summer-autumn precipitation. Our reconstruction reveals inter-annual to multi-decadal scale variation in hydroclimate of the region during the last 210 years, typically showing periods of below average precipitation extending from one to three decades and periods of above average precipitation, which were often less than a decade. Our results demonstrate that the last two decades (1995–2012) have been unusually wet (average summer-autumn precipitation of 310 mm) compared to the previous two centuries (average summer-autumn precipitation of 229 mm), coinciding with both an anomalously high frequency and intensity of tropical cyclones in northwest Australia and the dominance of the positive phase of the Southern Annular Mode. PMID:26039148

  14. Evaluation of the seasonal and annual abortifacient risk of western juniper trees on Oregon rangelands

    Science.gov (United States)

    Needles from ponderosa pine (Pinus ponderosa) trees are known to cause late term abortions in cattle. Recently, there have been several reports of abortion rates of 10-15% within cattle herds in Oregon after cattle were pastured in areas with abundant western juniper trees (Juniperus occidentalis)....

  15. Impacts of dwarf mistletoe on the physiology of host Tsuga heterophylla trees as recorded in tree-ring C and O stable isotopes

    Science.gov (United States)

    D. E. Marias; F. C. Meinzer; D. R. Woodruff; D. C. Shaw; S. L. Voelker; Steven W. Oak; William J. Otrosina; William D. Smith; Kamal J.K. Gandhi

    2014-01-01

    Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture and photosynthetic gas exchange and can eventually induce tree death. To investigate the long-term (1886–2010) impacts of dwarf mistletoe on the growth and gas exchange characteristics of host western hemlock, we...

  16. Impacts of dwarf mistletoe on the physiology of host Tsuga heterophylla trees as recorded in tree ring C and O stable isotopes

    Science.gov (United States)

    • Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture, and photosynthetic gas exchange and can eventually induce tree death. • To investigate long-term impacts of dwarf mistletoe...

  17. Intra-annual dynamics of non-structural carbohydrates in the cambium of mature conifer trees reflects radial growth demands.

    Science.gov (United States)

    Simard, Sonia; Giovannelli, Alessio; Treydte, Kerstin; Traversi, Maria Laura; King, Gregory M; Frank, David; Fonti, Patrick

    2013-09-01

    The presence of soluble carbohydrates in the cambial zone, either from sugars recently produced during photosynthesis or from starch remobilized from storage organs, is necessary for radial tree growth. However, considerable uncertainties on carbohydrate dynamics and the consequences on tree productivity exist. This study aims to better understand the variation in different carbon pools at intra-annual resolution by quantifying how cambial zone sugar and starch concentrations fluctuate over the season and in relation to cambial phenology. A comparison between two physiologically different species growing at the same site, i.e., the evergreen Picea abies Karst. and the deciduous Larix decidua Mill., and between L. decidua from two contrasting elevations, is presented to identify mechanisms of growth limitation. Results indicate that the annual cycle of sugar concentration within the cambial zone is coupled to the process of wood formation. The highest sugar concentration is observed when the number of cells in secondary wall formation and lignification stages is at a maximum, subsequent to most radial growth. Starch disappears in winter, while other freeze-resistant non-structural carbohydrates (NSCs) increase. Slight differences in NSC concentration between species are consistent with the differing climate sensitivity of the evergreen and deciduous species investigated. The general absence of differences between elevations suggests that the cambial activity of trees growing at the treeline was not limited by the availability of carbohydrates at the cambial zone but instead by environmental controls on the growing season duration.

  18. Importance of photoperiods in determining temporal pattern of annual testicular events in rose-ringed parakeet (Psittacula krameri).

    Science.gov (United States)

    Maitra, S K; Dey, M

    1992-01-01

    Male rose-ringed parakeets (Psittacula krameri) were transferred to a long photoperiod (LP; LD 16:8) or a short photoperiod (SP; LD 8:16) for 45 or 90 days on four dates corresponding to the beginnings of different reproductive phases in an annual testicular cycle, and testicular responsiveness was evaluated by comparison with the testicular volume, weight, seminiferous tubular diameter, and germ cell profiles of birds in a natural photoperiod (NP). Exposure of birds to LP during the progressive phase (November) led to precocious maturation of testes after 45 days, but induced regression at 90 days. After showing retarded gametogenic functions at 45 days, parallel (November) SP birds exhibited an accelerated rate of germ cell formation at day 90. During the prebreeding phase (January), there were no remarkable differences in any features of testes among NP. LP, and SP birds at 45 days, but gonadal involution in LP parakeets and active spermatogenesis in SP birds occurred after 90 days. The testes did not show any response to LP or SP for 45 and 90 days when the birds were transferred to altered photoperiods during the breeding (March) and preparatory (June) phases, indicating that the parakeets were photorefractory for at least 6 months (March through September). The results also suggest that initiation and termination of seasonal gametogenic activity in parakeets are possibly functions of endogenous rhythmicity or extraphotoperiodic environmental factors. Duration of light may have certain influences on the attainment of annual peak in spermatogenesis, but in all probability the species has a low photoperiod threshold for induction of testicular growth.

  19. [Responses of Pinus tabulaeformis forest ecosystem in North China to climate change and elevated CO2: a simulation based on BIOME-BGC model and tree-ring data].

    Science.gov (United States)

    He, Jun-Jie; Peng, Xing-Yuan; Chen, Zhen-Ju; Cui, Ming-Xing; Zhang, Xian-Liang; Zhou, Chang-Hong

    2012-07-01

    Based on BIOME-BGC model and tree-ring data, a modeling study was conducted to estimate the dynamic changes of the net primary productivity (NPP) of Pinus tabulaeformis forest ecosystem in North China in 1952-2008, and explore the responses of the radial growth and NPP to regional climate warming as well as the dynamics of the NPP in the future climate change scenarios. The simulation results indicated the annual NPP of the P. tabulaeformis ecosystem in 1952-2008 fluctuated from 244.12 to 645.31 g C x m(-2) x a(-1), with a mean value of 418.6 g C x m(-2) x a(-1) The mean air temperature in May-June and the precipitation from previous August to current July were the main factors limiting the radial growth of P. tabulaeformis and the NPP of P. tabulaeformis ecosystem. In the study period, both the radial growth and the NPP presented a decreasing trend due to the regional warming and drying climate condition. In the future climate scenarios, the NPP would have positive responses to the increase of air temperature, precipitation, and their combination. The elevated CO2 would benefit the increase of the NPP, and the increment would be about 16.1% due to the CO2 fertilization. At both ecosystem and regional scales, the tree-ring data would be an ideal proxy to predict the ecosystem dynamic change, and could be used to validate and calibrate the process-based ecosystem models including BIOME-BGC.

  20. Aridity changes in the temperate-Mediterranean transition of the Andes since ad 1346 reconstructed from tree-rings

    Energy Technology Data Exchange (ETDEWEB)

    Christie, Duncan A.; Quesne, Carlos le [Universidad Austral de Chile, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); Boninsegna, Jose A.; Morales, Mariano S.; Villalba, Ricardo [Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales, IANIGLA, Departamento de Dendrocronologia e Historia Ambiental, Mendoza (Argentina); Cleaveland, Malcolm K.; Stahle, David W. [University of Arkansas Fayetteville, Tree-Ring Laboratory, Department of Geosciences, Fayetteville, AR (United States); Lara, Antonio [Universidad Austral de Chile, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); Universidad Austral de Chile, Forest Ecosystem Services under Climatic Fluctuations (Forecos), Valdivia (Chile); Mudelsee, Manfred [Climate Risk Analysis, Hanover (Germany); Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany)

    2011-04-15

    The Andes Cordillera acts as regional ''Water Towers'' for several countries and encompasses a wide range of ecosystems and climates. Several hydroclimatic changes have been described for portions of the Andes during recent years, including glacier retreat, negative precipitation trends, an elevation rise in the 0 isotherm, and changes in regional streamflow regimes. The Temperate-Mediterranean transition (TMT) zone of the Andes (35.5 -39.5 S) is particularly at risk to climate change because it is a biodiversity hotspot with heavy human population pressure on water resources. In this paper we utilize a new tree-ring network of Austrocedrus chilensis to reconstruct past variations in regional moisture in the TMT of the Andes by means of the Palmer Drought Severity Index (PDSI). The reconstruction covers the past 657 years and captures interannual to decadal scales of variability in late spring-early summer PDSI. These changes are related to the north-south oscillations in moisture conditions between the Mediterranean and Temperate climates of the Andes as a consequence of the latitudinal position of the storm tracks forced by large-scale circulation modes. Kernel estimation of occurrence rates reveals an unprecedented increment of severe and extreme drought events during the last century in the context of the previous six centuries. Moisture conditions in our study region are linked to tropical and high-latitude ocean-atmospheric forcing, with PDSI positively related to Nino-3.4 SST during spring and strongly negatively correlated with the Antarctic Oscillation (AAO) during summer. Geopotential anomaly maps at 500-hPa show that extreme dry years are tightly associated with negative height anomalies in the Ross-Amundsen Seas, in concordance with the strong negative relationship between PDSI and AAO. The twentieth century increase in extreme drought events in the TMT may not be related to ENSO but to the positive AAO trend during late-spring and

  1. Climate signals in a multispecies tree-ring network from central and southern Italy and reconstruction of the late summer temperatures since the early 1700s

    Science.gov (United States)

    Leonelli, Giovanni; Coppola, Anna; Salvatore, Maria Cristina; Baroni, Carlo; Battipaglia, Giovanna; Gentilesca, Tiziana; Ripullone, Francesco; Borghetti, Marco; Conte, Emanuele; Tognetti, Roberto; Marchetti, Marco; Lombardi, Fabio; Brunetti, Michele; Maugeri, Maurizio; Pelfini, Manuela; Cherubini, Paolo; Provenzale, Antonello; Maggi, Valter

    2017-11-01

    A first assessment of the main climatic drivers that modulate the tree-ring width (RW) and maximum latewood density (MXD) along the Italian Peninsula and northeastern Sicily was performed using 27 forest sites, which include conifers (RW and MXD) and broadleaves (only RW). Tree-ring data were compared using the correlation analysis of the monthly and seasonal variables of temperature, precipitation and standardized precipitation index (SPI, used to characterize meteorological droughts) against each species-specific site chronology and against the highly sensitive to climate (HSTC) chronologies (based on selected indexed individual series). We find that climate signals in conifer MXD are stronger and more stable over time than those in conifer and broadleaf RW. In particular, conifer MXD variability is directly influenced by the late summer (August, September) temperature and is inversely influenced by the summer precipitation and droughts (SPI at a timescale of 3 months). The MXD sensitivity to August-September (AS) temperature and to summer drought is mainly driven by the latitudinal gradient of summer precipitation amounts, with sites in the northern Apennines showing stronger climate signals than sites in the south. Conifer RW is influenced by the temperature and drought of the previous summer, whereas broadleaf RW is more influenced by summer precipitation and drought of the current growing season. The reconstruction of the late summer temperatures for the Italian Peninsula for the past 300 years, based on the HSTC chronology of conifer MXD, shows a stable model performance that underlines periods of climatic cooling (and likely also wetter conditions) in 1699, 1740, 1814, 1914 and 1938, and follows well the variability of the instrumental record and of other tree-ring-based reconstructions in the region. Considering a 20-year low-pass-filtered series, the reconstructed temperature record consistently deviates divergence may also be due to the precipitation

  2. Climate signals in a multispecies tree-ring network from central and southern Italy and reconstruction of the late summer temperatures since the early 1700s

    Directory of Open Access Journals (Sweden)

    G. Leonelli

    2017-11-01

    Full Text Available A first assessment of the main climatic drivers that modulate the tree-ring width (RW and maximum latewood density (MXD along the Italian Peninsula and northeastern Sicily was performed using 27 forest sites, which include conifers (RW and MXD and broadleaves (only RW. Tree-ring data were compared using the correlation analysis of the monthly and seasonal variables of temperature, precipitation and standardized precipitation index (SPI, used to characterize meteorological droughts against each species-specific site chronology and against the highly sensitive to climate (HSTC chronologies (based on selected indexed individual series. We find that climate signals in conifer MXD are stronger and more stable over time than those in conifer and broadleaf RW. In particular, conifer MXD variability is directly influenced by the late summer (August, September temperature and is inversely influenced by the summer precipitation and droughts (SPI at a timescale of 3 months. The MXD sensitivity to August–September (AS temperature and to summer drought is mainly driven by the latitudinal gradient of summer precipitation amounts, with sites in the northern Apennines showing stronger climate signals than sites in the south. Conifer RW is influenced by the temperature and drought of the previous summer, whereas broadleaf RW is more influenced by summer precipitation and drought of the current growing season. The reconstruction of the late summer temperatures for the Italian Peninsula for the past 300 years, based on the HSTC chronology of conifer MXD, shows a stable model performance that underlines periods of climatic cooling (and likely also wetter conditions in 1699, 1740, 1814, 1914 and 1938, and follows well the variability of the instrumental record and of other tree-ring-based reconstructions in the region. Considering a 20-year low-pass-filtered series, the reconstructed temperature record consistently deviates < 1 °C from the instrumental

  3. Nitrogen deposition outweighs climatic variability in driving annual growth rate of canopy beech trees: Evidence from long-term growth reconstruction across a geographic gradient.

    Science.gov (United States)

    Gentilesca, Tiziana; Rita, Angelo; Brunetti, Michele; Giammarchi, Francesco; Leonardi, Stefano; Magnani, Federico; van Noije, Twan; Tonon, Giustino; Borghetti, Marco

    2018-07-01

    In this study, we investigated the role of climatic variability and atmospheric nitrogen deposition in driving long-term tree growth in canopy beech trees along a geographic gradient in the montane belt of the Italian peninsula, from the Alps to the southern Apennines. We sampled dominant trees at different developmental stages (from young to mature tree cohorts, with tree ages spanning from 35 to 160 years) and used stem analysis to infer historic reconstruction of tree volume and dominant height. Annual growth volume (G V ) and height (G H ) variability were related to annual variability in model simulated atmospheric nitrogen deposition and site-specific climatic variables, (i.e. mean annual temperature, total annual precipitation, mean growing period temperature, total growing period precipitation, and standard precipitation evapotranspiration index) and atmospheric CO 2 concentration, including tree cambial age among growth predictors. Generalized additive models (GAM), linear mixed-effects models (LMM), and Bayesian regression models (BRM) were independently employed to assess explanatory variables. The main results from our study were as follows: (i) tree age was the main explanatory variable for long-term growth variability; (ii) GAM, LMM, and BRM results consistently indicated climatic variables and CO 2 effects on G V and G H were weak, therefore evidence of recent climatic variability influence on beech annual growth rates was limited in the montane belt of the Italian peninsula; (iii) instead, significant positive nitrogen deposition (N dep ) effects were repeatedly observed in G V and G H ; the positive effects of N dep on canopy height growth rates, which tended to level off at N dep values greater than approximately 1.0 g m -2  y -1 , were interpreted as positive impacts on forest stand above-ground net productivity at the selected study sites. © 2018 John Wiley & Sons Ltd.

  4. Regional drought shifts (1710-2010) in East Central Asia and linkages with atmospheric circulation recorded in tree-ring δ18O

    Science.gov (United States)

    Xu, Guobao; Liu, Xiaohong; Trouet, Valerie; Treydte, Kerstin; Wu, Guoju; Chen, Tuo; Sun, Weizhen; An, Wenling; Wang, Wenzhi; Zeng, Xiaomin; Qin, Dahe

    2018-04-01

    Drought occurrence and duration in central Asia are of important socioeconomic, ecological, and geophysical significance and have received increasing research attention in recent years. Understanding long-term drought trends and their driving forces require reliable records of past drought variability with broad spatial representativeness. Here, we compiled four tree-ring δ18O records from eastern central Asia (ECA) and composited them into a drought-sensitive proxy to explore regional ECA moisture variations over the past 301 years (1710-2010 CE). A robust regional standardized precipitation-evapotranspiration index (SPEI) reconstruction was established based on the tree-ring cellulose δ18O fractionation mechanism and statistically significant proxy-climate relationships. We identified prominent droughts in 1710-1770, 1810-1830, and the beginning of the twenty-first century, and a regime shift to a persistently wet period from the 1880s to 2000. Our reconstruction reveals the impact of drought and pluvial patterns on the decline of Zhungar Empire, and on historical agricultural and socio-economical activities, including increased migration into ECA during the 1770-1800 pluvial. Our findings also suggest that wet conditions in the twentieth century in ECA were related to a strengthening of the westerly circulation and thus shed light on large-scale atmospheric circulation dynamics in central Asia.

  5. Linkages Between Hemispheric and Regional Circulation Features Over the Past Millennium Inferred From a Network of Long Tree-Ring Chronologies in the Southwestern USA.

    Science.gov (United States)

    Ni, F.; Hughes, M. K.; Funkhouser, G.

    2003-12-01

    Features of large-scale atmospheric/oceanic circulation at hemispheric and regional scale affect the many moisture-sensitive, well-replicated millennial length tree-ring records in the Western US that span all the last millennium. This tree-ring variability may be associated with the Pacific Decadal Oscillation (PDO), the Southern Oscillation Index (SOI) and the Southwest Trough Index, all of which directly influence climate variations in the American Southwest. 1000-year atmospheric/oceanic time series based in these associations were then linked with the observed and previously reconstructed summer Palmer Drought Severity Index (PDSI) in western US, providing a decadal to multi-century perspective on climate/circulation variability. Hemispheric and regional climate association tend to be stronger during sudden reversals from dry to wet which were not uncommon throughout the millennium, such as the 1970s PDO reversal which followed the 1950s drought, the 1610s wet interval that followed the 16th century mega drought, and the late 11th, early 12th centuries. Proxy and instrumental data suggest that significant regional anomalous dry (wet) periods over the last millennium (for example in the 1580s and 1950s) coincided with infrequent (frequent) short-wave trough activity. This probably teleconnected with cold sea surface temperature (SST) and high sea level pressure (SLP) over the eastern North Pacific that was enhanced by a greater number of in-phase cold-ENSO and PDO events.

  6. Lack of genetic variation in tree ring delta13C suggests a uniform, stomatally-driven response to drought stress across Pinus radiata genotypes.

    Science.gov (United States)

    Rowell, Douglas M; Ades, Peter K; Tausz, Michael; Arndt, Stefan K; Adams, Mark A

    2009-02-01

    We assessed the variation in delta(13)C signatures of Pinus radiata D. Don stemwood taken from three genetic trials in southern Australia. We sought to determine the potential of using delta(13)C signatures as selection criteria for drought tolerance. Increment cores were taken from P. radiata and were used to determine the basal area increment and the delta(13)C signature of extracted cellulose. Both growth increment and cellulose delta(13)C were affected by water availability. Growth increment and delta(13)C were negatively correlated suggesting that growth was water-limited. While there was significant genetic variation in growth, there was no significant genetic variation in cellulose delta(13)C of tree rings. This suggests that different genotypes of P. radiata display significant differences in growth and yet respond similarly to drought stress. The delta(13)C response to drought stress was more due to changes in stomatal conductance than to the variation in photosynthetic capacity, and this may explain the lack of genetic variation in delta(13)C. The lack of genetic variation in cellulose delta(13)C of tree rings precludes its use as a selection criterion for drought tolerance among P. radiata genotypes.

  7. Decreasing Indian summer monsoon on the northern Indian sub-continent during the last 180 years: evidence from five tree-ring cellulose oxygen isotope chronologies

    Science.gov (United States)

    Xu, Chenxi; Sano, Masaki; Priyadarshan Dimri, Ashok; Ramesh, Rengaswamy; Nakatsuka, Takeshi; Shi, Feng; Guo, Zhengtang

    2018-05-01

    We have constructed a regional tree-ring cellulose oxygen isotope (δ18O) record for the northern Indian sub-continent based on two new records from northern India and central Nepal and three published records from northwestern India, western Nepal and Bhutan. The record spans the common interval from 1743 to 2008 CE. Correlation analysis reveals that the record is significantly and negatively correlated with the three regional climatic indices: all India rainfall (AIR; r = -0.5, p changes in the ISM. The record exhibits significant interannual and long-term variations. Interannual changes are closely related to the El Niño-Southern Oscillation (ENSO), which indicates that the ISM was affected by ENSO in the past. However, the ISM-ENSO relationship was not consistent over time, and it may be partly modulated by Indian Ocean sea surface temperature (SST). Long-term changes in the regional tree-ring δ18O record indicate a possible trend of weakened ISM intensity since 1820. Decreasing ISM activity is also observed in various high-resolution ISM records from southwest China and Southeast Asia, and may be the result of reduced land-ocean thermal contrasts since 1820 CE.

  8. Predictive models for radial sap flux variation in coniferous, diffuse-porous and ring-porous temperate trees.

    Science.gov (United States)

    Berdanier, Aaron B; Miniat, Chelcy F; Clark, James S

    2016-08-01

    Accurately scaling sap flux observations to tree or stand levels requires accounting for variation in sap flux between wood types and by depth into the tree. However, existing models for radial variation in axial sap flux are rarely used because they are difficult to implement, there is uncertainty about their predictive ability and calibration measurements are often unavailable. Here we compare different models with a diverse sap flux data set to test the hypotheses that radial profiles differ by wood type and tree size. We show that radial variation in sap flux is dependent on wood type but independent of tree size for a range of temperate trees. The best-fitting model predicted out-of-sample sap flux observations and independent estimates of sapwood area with small errors, suggesting robustness in the new settings. We develop a method for predicting whole-tree water use with this model and include computer code for simple implementation in other studies. Published by Oxford University Press 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  9. Needle age and season influence photosynthetic temperature response and total annual carbon uptake in mature Picea mariana trees

    Science.gov (United States)

    Jensen, Anna M.; Warren, Jeffrey M.; Hanson, Paul J.; Childs, Joanne; Wullschleger, Stan D.

    2015-01-01

    Background and Aims The carbon (C) balance of boreal terrestrial ecosystems is sensitive to increasing temperature, but the direction and thresholds of responses are uncertain. Annual C uptake in Picea and other evergreen boreal conifers is dependent on seasonal- and cohort-specific photosynthetic and respiratory temperature response functions, so this study examined the physiological significance of maintaining multiple foliar cohorts for Picea mariana trees within an ombrotrophic bog ecosystem in Minnesota, USA. Methods Measurements were taken on multiple cohorts of needles for photosynthetic capacity, foliar respiration (Rd) and leaf biochemistry and morphology of mature trees from April to October over 4 years. The results were applied to a simple model of canopy photosynthesis in order to simulate annual C uptake by cohort age under ambient and elevated temperature scenarios. Key Results Temperature responses of key photosynthetic parameters [i.e. light-saturated rate of CO2 assimilation (Asat), rate of Rubisco carboxylation (Vcmax) and electron transport rate (Jmax)] were dependent on season and generally less responsive in the developing current-year (Y0) needles compared with 1-year-old (Y1) or 2-year-old (Y2) foliage. Temperature optimums ranged from 18·7 to 23·7, 31·3 to 38·3 and 28·7 to 36·7 °C for Asat, Vcmax and Jmax, respectively. Foliar cohorts differed in their morphology and photosynthetic capacity, which resulted in 64 % of modelled annual stand C uptake from Y1&2 cohorts (LAI 0·67 m2 m−2) and just 36 % from Y0 cohorts (LAI 0·52 m2 m−2). Under warmer climate change scenarios, the contribution of Y0 cohorts was even less; e.g. 31 % of annual C uptake for a modelled 9 °C rise in mean summer temperatures. Results suggest that net annual C uptake by P. mariana could increase under elevated temperature, and become more dependent on older foliar cohorts. Conclusions Collectively, this study illustrates the physiological and

  10. Variation of Maximum Tree Height and Annual Shoot Growth of Smith Fir at Various Elevations in the Sygera Mountains, Southeastern Tibetan Plateau

    Science.gov (United States)

    Wang, Yafeng; Čufar, Katarina; Eckstein, Dieter; Liang, Eryuan

    2012-01-01

    Little is known about tree height and height growth (as annual shoot elongation of the apical part of vertical stems) of coniferous trees growing at various altitudes on the Tibetan Plateau, which provides a high-elevation natural platform for assessing tree growth performance in relation to future climate change. We here investigated the variation of maximum tree height and annual height increment of Smith fir (Abies georgei var. smithii) in seven forest plots (30 m×40 m) along two altitudinal transects between 3,800 m and 4,200/4,390 m above sea level (a.s.l.) in the Sygera Mountains, southeastern Tibetan Plateau. Four plots were located on north-facing slopes and three plots on southeast-facing slopes. At each site, annual shoot growth was obtained by measuring the distance between successive terminal bud scars along the main stem of 25 trees that were between 2 and 4 m high. Maximum/mean tree height and mean annual height increment of Smith fir decreased with increasing altitude up to the tree line, indicative of a stress gradient (the dominant temperature gradient) along the altitudinal transect. Above-average mean minimum summer (particularly July) temperatures affected height increment positively, whereas precipitation had no significant effect on shoot growth. The time series of annual height increments of Smith fir can be used for the reconstruction of past climate on the southeastern Tibetan Plateau. In addition, it can be expected that the rising summer temperatures observed in the recent past and anticipated for the future will enhance Smith fir's growth throughout its altitudinal distribution range. PMID:22396738

  11. Evaluation of the seasonal and annual abortifacient risk of western juniper trees on Oregon rangelands: Abortion risk of western juniper trees

    Science.gov (United States)

    Western juniper trees can cause late term abortions in cattle, similar to ponderosa pine trees. Analyses of western juniper trees from 35 locations across the state of Oregon suggest that western juniper trees in all areas present an abortion risk in pregnant cattle. Results from this study demonstr...

  12. Extreme pointer years in tree-ring records of Central Spain as evidence of volcanic eruptions (Huaynaputina, Peru, 1600 AC) and other climatic events

    Science.gov (United States)

    Génova, M.

    2011-12-01

    The study of pointer years based on the numerous tree-ring chronologies of the central Iberian Peninsula (Sierra de Guadarrama) could provide complementary information about climate variability over the last 405 years. In total, 64 pointer years have been identified: 30 negative (representing minimum growths) and 34 positive (representing maximum growths), the most significant of these being 1601, 1963 and 1996 for the negative ones, and 1734 and 1737 for the positive ones. Given that summer precipitation has been the most incident factor in the general variability of growth of Pinus in the Sierra de Guadarrama in the second half of the 20th century, it is also an explanatory factor in almost 50% of the extreme growths. Furthermore, the data show that there has been variability over the centuries in the distribution of the frequencies of pointer years and intervals. The first half of the 17th century, together with the second half of the 20th century, constitute the two most notable periods for the frequency of negative pointer years in Central Spain. This variability was sufficiently notable to affirm that, both in the 17th and 20th centuries, the macroclimatic anomalies that affected growth were more frequent and more extreme than in the other two centuries analysed. The period 1600-1602 is of special significance, being one of the most unfavourable for tree growth in the centre of Spain, with 1601 representing the minimum index in the regional chronology. It is possible to infer that these phenomena are the effect of the eruption of Huaynaputina, which occurred in Peru at the beginning of 1600 AD. This is the first time that the effects of this eruption in the tree-ring records of central and southern Europe have been demonstrated.

  13. Insensitivity of Tree-Ring Growth to Temperature and Precipitation Sharpens the Puzzle of Enhanced Pre-Eruption NDVI on Mt. Etna (Italy).

    Science.gov (United States)

    Seiler, Ruedi; Kirchner, James W; Krusic, Paul J; Tognetti, Roberto; Houlié, Nicolas; Andronico, Daniele; Cullotta, Sebastiano; Egli, Markus; D'Arrigo, Rosanne; Cherubini, Paolo

    2017-01-01

    On Mt. Etna (Italy), an enhanced Normalized Difference in Vegetation Index (NDVI) signature was detected in the summers of 2001 and 2002 along a distinct line where, in November 2002, a flank eruption subsequently occurred. These observations suggest that pre-eruptive volcanic activity may have enhanced photosynthesis along the future eruptive fissure. If a direct relation between NDVI and future volcanic eruptions could be established, it would provide a straightforward and low-cost method for early detection of upcoming eruptions. However, it is unclear if, or to what extent, the observed enhancement of NDVI can be attributed to volcanic activity prior to the subsequent eruption. We consequently aimed at determining whether an increase in ambient temperature or additional water availability owing to the rise of magma and degassing of water vapour prior to the eruption could have increased photosynthesis of Mt. Etna's trees. Using dendro-climatic analyses we quantified the sensitivity of tree ring widths to temperature and precipitation at high elevation stands on Mt. Etna. Our findings suggest that tree growth at high elevation on Mt. Etna is weakly influenced by climate, and that neither an increase in water availability nor an increase in temperature induced by pre-eruptive activity is a plausible mechanism for enhanced photosynthesis before the 2002/2003 flank eruption. Our findings thus imply that other, yet unknown, factors must be sought as causes of the pre-eruption enhancement of NDVI on Mt. Etna.

  14. The influence of summertime fog and overcast clouds on the growth of a coastal Californian pine: a tree-ring study.

    Science.gov (United States)

    Williams, A Park; Still, Christopher J; Fischer, Douglas T; Leavitt, Steven W

    2008-06-01

    The coast of California is home to numerous rare, endemic conifers and other plants that are limited in distribution by drought sensitivity and the summer-dry climate that prevails across most of the state. Ecologists have long assumed that some coastal plant populations survived the early Pleistocene transition to a warmer and drier environment because they benefit from frequent fog and stratus clouds that provide water and shade during the rainless summer. One such population is that of Torrey pine (Pinus torreyana ssp. Insularis) on Santa Rosa Island in Channel Islands National Park. Here we report that the tree-ring width record from this population indicates strong growth sensitivities to summer fog drip and cloud shading. We quantified the effects of summer cloud cover by comparing ring-width indices to coastal airport cloud-frequency records (1944-2004). For the first time observed, summertime cloud frequency correlated positively with ring-width indices, regardless of whether the effect of rainfall was first removed from the ring-width record. The effect of ground-level fog was strongest in July early mornings (03:00 PST, R(2) = 0.262, P clouds high enough to provide shade but not fog water was also strongest in July, but climbed steadily throughout the day before becoming strongest in late afternoon (16:00-18:00 PST, R(2) = 0.148, P clouds is strongly affected by pre-summer rainfall. A change in the height and/or timing of coastal cloud formation with climate change would likely affect this and other populations of California's coastal vegetation.

  15. Enhanced tools for predicting annual stone pine (Pinus pinea L.) cone production at tree and forest scale in Inner Spain

    Energy Technology Data Exchange (ETDEWEB)

    Calama, R.; Gordo, J.; Madrigal, G.; Mutke, S.; Conde, M.; Montero, G.; Pardos, M.

    2016-07-01

    Aim of the study: To present a new spatiotemporal model for Pinus pinea L. annual cone production with validity for Spanish Northen Plateau and Central Range regions. The new model aims to deal with detected deficiencies in previous models: temporal shortage, overestimation of cone production on recent years, incompatibility with data from National Forest Inventory, difficulty for upscaling and ignorance of the inhibitory process due to resource depletion. Area of study: Spanish Northern Plateau and Central Range regions, covering an area where stone pine occupies more than 90,000 ha. Material and methods: Fitting data set include 190 plots and more than 1000 trees were cone production has been annually collected from 1996 to 2014. Models were fitted independently for each region, by means of zero-inflated log normal techniques. Validation of the models was carried out over the annual series of cone production at forest scale. Results: The spatial and temporal factors influencing cone production are similar in both regions, thus the main regional differences in cone yield are related with differences in the phenological timing, the intensity of the influent factors and forest intrinsic conditions. A significant inhibition of floral induction by resource depletion was detected and included into the model. Upscaling the model results in accurate prediction at forest scale. Research highlights: [1] The new model for annual cone production surpass the detected deficiencies of previous models, accurately predicting recent decay in cone production; [2] Regional differences in cone production are due to phenological and seasonal climatic differences rather than to between provenances genetic differences. (Author)

  16. Tree growth and vegetation activity at the ecosystem-scale in the eastern Mediterranean

    Science.gov (United States)

    Coulthard, Bethany L.; Touchan, Ramzi; Anchukaitis, Kevin J.; Meko, David M.; Sivrikaya, Fatih

    2017-08-01

    Linking annual tree growth with remotely-sensed terrestrial vegetation indices provides a basis for using tree rings as proxies for ecosystem primary productivity over large spatial and long temporal scales. In contrast with most previous tree ring/remote sensing studies that have focused on temperature-limited boreal and taiga environments, here we compare the normalized difference vegetation index (NDVI) with a network of Pinus brutia tree ring width chronologies collected along ecological gradients in semiarid Cyprus, where both radial tree growth and broader vegetation activity are controlled by drought. We find that the interaction between precipitation, elevation, and land-cover type generate a relationship between radial tree growth and NDVI. While tree ring chronologies at higher-elevation forested sites do not exhibit climate-driven linkages with NDVI, chronologies at lower-elevation dry sites are strongly correlated with NDVI during the winter precipitation season. At lower-elevation sites, land cover is dominated by grasslands and shrublands and tree ring widths operate as a proxy for ecosystem-scale vegetation activity. Tree rings can therefore be used to reconstruct productivity in water-limited grasslands and shrublands, where future drought stress is expected to alter the global carbon cycle, biodiversity, and ecosystem functioning in the 21st century.

  17. Inference of past atmospheric delta13C and P/sub CO2/ from 13C/12C measurements in tree rings

    International Nuclear Information System (INIS)

    Leavitt, S.W.

    1982-01-01

    Carbon dioxide release from fossil-fuel burning is significant enough that we may soon experience perceptible changes in climate with important human consequences. An accurate reconstruction of past 13 C/ 12 C ratios of atmospheric CO 2 may provide key constraints on the historical activity of the biosphere as CO 2 source or sink. Tree rings appear to be a repository of this information but there is much noise in the collection of previous reconstructions, presumably associated with site selection, radial variability, choice of representative wood chemical constituent, and subtle effects of climate on fractionation. This study attempts to avoid these pitfalls and develop a 50-yr delta 13 C/sub ATM/ record from juniper trees (genus Juniperus), in fact, by taking advantage of the influence of climate on fractionation. Trees were harvested from suitable sites in close proximity to weather stations with monthly records of temperature and precipitation. The most useful relationships for at most 7 of the 10 sites were delta 13 C with December temperature or precipitation, because the coefficients were nearly constant from one interval to the next and the intercepts differed. Local pollution effects are believed responsible for the three anomalous sites. The separation of these regression lines of different intervals is interpreted as the response of the trees to the changing delta 13 C of atmospheric CO 2 so that delta 13 C/sub ATM/ curves are constructed from this spacing. The shape of the best-fit reconstruction suggests the biosphere has acted as CO 2 source to about 1965 and may now be a net sink

  18. Evaluation of growth tree rings of Tipuana Tipu as biomonitoring of environmental pollution by synchrotron radiation total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Moreira, Silvana; Geraldo, Simoni Michetti; Canteras, Felippe Benavente

    2013-01-01

    The bioindicators, plants or animals capable to present qualitative and/or quantitative answers, when exposed to pollutant substances. Trees record and incorporate in their log, developed year after year, the impressions of the environment, becoming possible the study of the different environmental changes, including contamination, that have occurred over the life of these trees. The selected species, Tipuana Tipu, of the Leguminosae family, is native of Argentina and Bolivia and was introduced in Brazil as an ornamental plant. It is one of the most common trees in the urban landscaping in Sao Paulo city. The present project has as main objective the determination of the content of potentially toxic elements in samples of growth the tree rings of Tipuana Tipu, previously dated, collected in strategically locations of Sao Paulo, using Synchrotron Radiation Total Reflection X-Ray Fluorescence. Samples were also collected in the Piracicaba (SP), local of little access and small flow traffic. The SR-TXRF analysis was carried out in the X-ray Fluorescence Beamline at the Brazilian Synchrotron Light Source Laboratory, located in Campinas city, Sao Paulo State, Brazil. Some trace elements present concentrations higher than considered as normal in some periods. In this paper the highest value for Pb was 123.54 μg.g -1 considered as threshold value was observed for the period 1998 to 2000 for University of Sao Paulo, Butanta site. For the same period excessive level was also observed for samples collected in Piracicaba city. In Sao Paulo city, sample collected in the campus of University of Sao Paulo (Butanta), showed the highest toxicity, with concentration above the tolerable limit for Ti, Cr and Cu. For the samples collected in Piracicaba city the concentrations of Cr, Ni, Cu, and Pb exceeding the toxicity limits. (author)

  19. Evaluation of growth tree rings of Tipuana Tipu as biomonitoring of environmental pollution by synchrotron radiation total reflection X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Silvana; Geraldo, Simoni Michetti; Canteras, Felippe Benavente, E-mail: silvana@fec.unicamp.br, E-mail: felippe.canteras@gmail.com [Universidade Estadual de Campinas (FEC/UNICAMP), Campinas, SP (Brazil). Dept. de Saneamento e Ambiente

    2013-07-01

    The bioindicators, plants or animals capable to present qualitative and/or quantitative answers, when exposed to pollutant substances. Trees record and incorporate in their log, developed year after year, the impressions of the environment, becoming possible the study of the different environmental changes, including contamination, that have occurred over the life of these trees. The selected species, Tipuana Tipu, of the Leguminosae family, is native of Argentina and Bolivia and was introduced in Brazil as an ornamental plant. It is one of the most common trees in the urban landscaping in Sao Paulo city. The present project has as main objective the determination of the content of potentially toxic elements in samples of growth the tree rings of Tipuana Tipu, previously dated, collected in strategically locations of Sao Paulo, using Synchrotron Radiation Total Reflection X-Ray Fluorescence. Samples were also collected in the Piracicaba (SP), local of little access and small flow traffic. The SR-TXRF analysis was carried out in the X-ray Fluorescence Beamline at the Brazilian Synchrotron Light Source Laboratory, located in Campinas city, Sao Paulo State, Brazil. Some trace elements present concentrations higher than considered as normal in some periods. In this paper the highest value for Pb was 123.54 μg.g{sup -1} considered as threshold value was observed for the period 1998 to 2000 for University of Sao Paulo, Butanta site. For the same period excessive level was also observed for samples collected in Piracicaba city. In Sao Paulo city, sample collected in the campus of University of Sao Paulo (Butanta), showed the highest toxicity, with concentration above the tolerable limit for Ti, Cr and Cu. For the samples collected in Piracicaba city the concentrations of Cr, Ni, Cu, and Pb exceeding the toxicity limits. (author)

  20. IN SITU COMPARISON OF TREE-RING RESPONSES TO CLIMATE AND POPULATION GENETICS: THE NEED TO CONTROL FOR LOCAL CLIMATE AND SITE VARIABLES

    Directory of Open Access Journals (Sweden)

    Johann Mathias Housset

    2016-10-01

    Full Text Available Tree species responses to climate change will be greatly influenced by their evolutionary potential and their phenotypic plasticity. Investigating tree-rings responses to climate and population genetics at the regional scale is therefore crucial in assessing the tree behaviour to climate change. This study combined in situ dendroclimatology and population genetics over a latitudinal gradient and compared the variations between the two at the intra- and inter-population levels. This approach was applied on the northern marginal populations of Thuja occidentalis (eastern white-cedar in the Canadian boreal forest. We aimed first to assess the radial growth variability (response functional trait within populations across the gradient and to compare it with the genetic diversity (microsatellites. Second, we investigated the variability in the growth response to climate at the regional scale through the radial growth-climate relationships, and tested its correlation with environmental variables and population genetic structure. Model selection based on the Akaike Information Criteria revealed that the growth synchronicity between pairs of trees of a population covariates with both the genetic diversity of this population and the amount of precipitation (inverse correlation, although these variables only explained a small fraction of the observed variance. At the regional scale, variance partitioning and partial redundancy analysis indicate that the growth response to climate was greatly modulated by stand environmental variables, suggesting predominant plastic variations in growth-response to climate. Combining in situ dendroclimatology and population genetics is a promising way to investigate species’ response capacity to climate change in natural stands. We stress the need to control for local climate and site conditions effects on dendroclimatic response to climate to avoid misleading conclusions regarding the associations with genetic variables.

  1. Tree rings reveal a major episode of forest mortality in the late 18th century on the Tibetan Plateau

    Science.gov (United States)

    Fang, Ouya; Alfaro, René I.; Zhang, Qi-Bin

    2018-04-01

    There is a growing research interest on studying forest mortality in relation to ongoing climate warming, but little is known about such events in past history. The study of past forest mortality provides valuable information for determining baselines that establish the normal parameters of functioning in forest ecosystems. Here we report a major episode of previously undocumented forest mortality in the late 18th century on the northern Tibetan Plateau, China. The event was not spatially uniform, in which a more severe mortality happened in dryer sites. We used dendrochronology to compare radial growth trajectories of individual trees from 11 sites in the region, and found that many trees showed positive growth trend, or growth release, during 1796-1800 CE. Growth releases are a proxy indicator of stand thinning caused by tree mortality. The growth release was preceded by an almost two-decade long growth reduction. Long-term drought related to weakened North Atlantic Oscillation and frequent El Niño events are the likely factors causing the tree mortality in a large area of the plateau. Our findings suggest that, besides the effect of drought in the late 18th century, large-scale forest mortality may be an additional factor that further deteriorated the environment and increased the intensity of dust storms.

  2. Temporal expansion of annual crop classification layers for the CONUS using the C5 decision tree classifier

    Science.gov (United States)

    Friesz, Aaron M.; Wylie, Bruce K.; Howard, Daniel M.

    2017-01-01

    Crop cover maps have become widely used in a range of research applications. Multiple crop cover maps have been developed to suite particular research interests. The National Agricultural Statistics Service (NASS) Cropland Data Layers (CDL) are a series of commonly used crop cover maps for the conterminous United States (CONUS) that span from 2008 to 2013. In this investigation, we sought to contribute to the availability of consistent CONUS crop cover maps by extending temporal coverage of the NASS CDL archive back eight additional years to 2000 by creating annual NASS CDL-like crop cover maps derived from a classification tree model algorithm. We used over 11 million records to train a classification tree algorithm and develop a crop classification model (CCM). The model was used to create crop cover maps for the CONUS for years 2000–2013 at 250 m spatial resolution. The CCM and the maps for years 2008–2013 were assessed for accuracy relative to resampled NASS CDLs. The CCM performed well against a withheld test data set with a model prediction accuracy of over 90%. The assessment of the crop cover maps indicated that the model performed well spatially, placing crop cover pixels within their known domains; however, the model did show a bias towards the ‘Other’ crop cover class, which caused frequent misclassifications of pixels around the periphery of large crop cover patch clusters and of pixels that form small, sparsely dispersed crop cover patches.

  3. Using intra annual density fluctuations and d13C to assess the impact of summer drought on Mediterranean ecosystem

    Science.gov (United States)

    Battipaglia, G.; Brand, W. A.; Linke, P.; Schaefer, I.; Noetzli, M.; Cherubini, P.

    2009-04-01

    Tree- ring growth and wood density have been used extensively as indicators of climate change, and tree-ring has been commonly applied as a proxy estimate for seasonal integration of temperatures and precipitation with annual resolution (Hughes 2002). While these relationships have been well established in temperate ecosystems (Fritts, 1976; Schweingruber, 1988, Briffa et al., 1998, 2004), in Mediterranean region dendrochronological studies are still scarce (Cherubini et al, 2003). In Mediterranean environment, trees may form intra-annual density fluctuations, also called "false rings" or "double rings" (Tingley 1937; Schulman 1938). They are usually induced by sudden drought events, occurring during the vegetative period, and, allowing intra-annual resolution, they may provide detailed information at a seasonal level, as well as species-specific sensitivity to drought. We investigated the variability of tree- ring width and carbon stable isotopes of a Mediterranean species, Arbutus unedo L., sampled on Elba island, (Tuscany, Italy). The samples were taken at two different sites, one characterized by wet and one by dry conditions. d13C was measured using Laser- Ablation- Combustion -GC-IRMS. Here, we present first results showing the impact of drought on tree growth and on false ring formation at the different sites and we underline the importance of using Laser Ablation to infer drought impact at the intra -annual level. Briffa KR, Schweingruber FH, Jones PD, Osborn TJ, Harris IC, Shiyatov SG, Vaganov EA, Grudd H (1998) Trees tell of past climates: but are they speaking less clearly today? Phil Transact Royal Soc London 353:65-73 Briffa KR, Osborn TJ, Schweingruber FH (2004) Large-scale temperature inferences from tree rings: a review. Glob Panet Change 40:11-26 Cherubini, P., B.L. Gartner, R. Tognetti, O.U. Bräker, W. Schoch & J.L. Innes. 2003. Identification, measurement and interpretation of tree rings in woody species from Mediterranean climates. Biol. Rev

  4. Can tree-ring isotopes (δ18O and δ13C) improve our understanding of hydroclimate variability in the Columbia River Basin?

    Science.gov (United States)

    Csank, A. Z.; Wise, E.; McAfee, S. A.

    2015-12-01

    The trajectory of incoming storms from the Pacific Ocean has a strong impact on hydroclimate in the Pacific Northwest. Shifts between zonal and meridional flow are a key influence on drought and pluvial regimes in both the PNW and the western United States as a whole. Circulation-dependent variability in the isotopic composition of precipitation can be recorded and potentially reconstructed using δ18O records derived from tree-rings. Here we present isotopic records of δ18O and δ13C from ponderosa pine (Pinus ponderosa) for the period 1950-2013 from six sites located in the lee of the Cascades in eastern Washington. Because of the orientation of the Cascades, zonal flow will result in an intensified rain shadow whereas meridional flow allows moisture to penetrate at a lower elevation leading to a lower rainout effect. This means zonal flow results in drier conditions in eastern Washington and the converse for meridional flow. We hypothesized that more depleted precipitation δ18O values will occur with periods of more zonal flow across the PNW and will be recorded by trees at our sites. Results show a strong relationship between our δ18O chronologies and winter precipitation (R = -0.50; p<0.001). δ13C chronologies from the same trees showed a relationship to prior fall/winter (pOct-pDec) precipitation (R = -0.46; p<0.005) suggesting a possible link to antecedent moisture conditions. With a focus on years with clear zonal and meridional flow regimes, we regressed the tree-ring δ18O anomaly against the instrumental record of total precipitation and compared the residual series to records of storm track for the period 1978-2008, and we found a detectable signal where the most depleted δ18O was generally associated with zonal flow and the most enriched δ18O with meridional flow. However, there are still some years where the relationship is unclear. Further work is aimed at understanding these anomalous years and extending our record beyond the instrumental

  5. Species-specific growth responses to climate variations in understory trees of a Central African rain forest

    NARCIS (Netherlands)

    Couralet, C.; Sterck, F.J.; Sass-Klaassen, U.; Acker, Van J.; Beekman, H.

    2010-01-01

    Basic knowledge of the relationships between tree growth and environmental variables is crucial for understanding forest dynamics and predicting vegetation responses to climate variations. Trees growing in tropical areas with a clear seasonality in rainfall often form annual growth rings. In the

  6. Climate effects on inter- and intra-annual larch stemwood anomalies in the Mongolian forest-steppe

    Science.gov (United States)

    Khishigjargal, Mookhor; Dulamsuren, Choimaa; Leuschner, Hanns Hubert; Leuschner, Christoph; Hauck, Markus

    2014-02-01

    Climate response of tree-ring width and intra-annual wood anomalies were studied in stands of Siberian larch (Larix sibirica) on Mt. Bogd Uul in the forest-steppe ecotone of Mongolia. Climate on Mt. Bogd Uul is characterized by an increase of the annual mean temperature by 1.5 K between 1965 and 2007, the lack of a long-term trend for annual precipitation and, with it, an increase in aridity. Tree-ring width increases with increasing June precipitation of the current year (June) and increasing late summer precipitation of the previous year. In >100-year old trees, also a negative correlation of tree-ring width with the July temperature of the year prior to tree-ring formation was found. Decreasing tree-ring width with increasing snowfall in December can be explained with the protection of the frost-sensitive eggs of gypsy moth by snow cover, which is a major herbivore of larch in Mongolia and causes reduction in the annual stem increment. The most significant change in wood anatomy was the decline of wide latewood, which is attributable to the increase of summer days with a mean temperature > 15 °C and drought periods in summer without precipitation. Increasing summer drought is also thought to have caused the repeated occurrence of missing rings since the 1960s, which were not observed in the late 19th and early 20th centuries.

  7. Summer Temperature Extremes in the Northern Rockies: A Tree-Ring-Based Reconstruction (1670-2014) from the Bighorn Mountains, WY

    Science.gov (United States)

    Hudson, A.; Alfaro-Sanchez, R.; Belmecheri, S.; Moore, D. J.; Trouet, V.

    2017-12-01

    Anthropogenic climate change has caused global temperatures to rise in recent decades. Temperatures at the regional scale are influenced by various factors including topography, atmospheric circulation, and seasonality that superimpose year-to-year variability on this global warming trend. Here, we develop a tree-ring based summer temperature reconstruction for the northern Rockies in order to investigate the drivers of the year-to-year temperature variability in this region. For this purpose, we sampled 10 sites in the semi-arid Bighorn Mountains, WY and developed two tree-ring width chronologies for differing elevations. The high elevation Picea engelmannii chronology (>2,630m) is positively correlated with July temperature variability, whereas the low elevation (<2,580m) chronology - consisting of Pinus contorta, Pseudotsuga menziesii, and Pinus albicaulis - is sensitive to summer precipitation and negatively correlated with June and July temperatures. A reconstruction based on a combination of the two chronologies explains 30% of the variance in regional June and July temperatures over the instrumental period, covers the period 1670-2014, and is representative for the central United States and southern Canada region. Our reconstruction shows significantly lower summer temperatures in the year following the 16 largest tropical eruptions from 1670 to the present. The reconstruction further captures the high summer temperatures during the 1930s dust bowl era and shows a steep increase in variance in the late 20th century. Enhanced late 20th century variance has also been detected in climate and ecosystem dynamics in the Northeast Pacific, which suggests an impact of an amplified meridional flow on northern Rockies summer temperatures.

  8. Regional difference of the start time of the recent warming in Eastern China: prompted by a 165-year temperature record deduced from tree rings in the Dabie Mountains

    Science.gov (United States)

    Cai, Qiufang; Liu, Yu; Duan, Bingchuang; Sun, Changfeng

    2018-03-01

    Tree-ring studies from tropical to subtropical regions are rarer than that from extratropical regions, which greatly limit our understanding of some critical climate change issues. Based on the tree-ring-width chronology of samples collected from the Dabie Mountains, we reconstructed the April-June mean temperature for this region with an explained variance of 46.8%. Five cold (1861-1869, 1889-1899, 1913-1920, 1936-1942 and 1952-1990) and three warm (1870-1888, 1922-1934 and 2000-2005) periods were identified in the reconstruction. The reconstruction not only agreed well with the instrumental records in and around the study area, but also showed good resemblance to previous temperature reconstructions from nearby regions, indicating its spatial and temporal representativeness of the temperature variation in the central part of eastern China. Although no secular warming trend was found, the warming trend since 1970 was unambiguous in the Dabie Mountains (0.064 °C/year). Further temperature comparison indicated that the start time of the recent warming in eastern China was regional different. It delayed gradually from north to south, starting at least around 1940 AD in the north part, around 1970 AD in the central part and around 1980s in the south part. This work enriches the high-resolution temperature reconstructions in eastern China. We expect that climate warming in the future would promote the radial growth of alpine Pinus taiwanensis in the subtropical areas of China, therefore promote the carbon capture and carbon storage in the Pinus taiwanensis forest. It also helps to clarify the regional characteristic of recent warming in eastern China.

  9. Comparison of stable carbon isotope ratios in the whole wood, cellulose and lignin of Oak tree-rings

    CSIR Research Space (South Africa)

    Loader, NJ

    2003-08-01

    Full Text Available The stable carbon isotope ratios (N13C) of whole wood, cellulose and acid-insoluble lignin from annual latewood increments of Quereus robur L., from modern and sub-fossil wood, were measured and their potential use as palaeo environmental indicators...

  10. Dating of dipterocarp tree rings: establishing a record of carbon cycling and climatic change in the tropics

    CSIR Research Space (South Africa)

    Robertson, I

    2004-10-01

    Full Text Available , Fuls A, Visser A. 2002. Accurate dating with radiocarbon from the atom bomb tests. South African Journal of Science 98: 437–438. Walsh RPD. 1996. Drought frequency changes in Sabah and adjacent parts of northern Borneo since the late nineteenth... car- bon) for sample rings 158–159 (PTA 8641) was found to have two intercepts, with the bomb carbon curve corresponding to the years AD 1978� 1 or AD 1962� 1 (Table 1). Although it has been stated that samples from the modern plateau cannot...

  11. Development of a C-14 detector and measurement of delta C-14 in dated tree rings grown in 1043 to 1055

    International Nuclear Information System (INIS)

    Oona, H.

    1979-01-01

    A proportional counter was constructed from plastic scintillator for measuring the C-14 contents in dendrochronologically dated tree ringas. The tree rings were individually converted to methane which, at one atmosphere pressure, was used as the counter gas. The wall, being a scintillator, serves as the 4π anti-coincidence shell for rejection of natural radioactivity in the material housing the proportional counter and penetrating cosmic ray muons. The output of the proportional counter, which is in anti-coincidence with the scintillation is recorded with a pulse height analyzer. After background subtraction, it yields the beta-decay spectrum of C-14 in the methane-filled proportional counter. The count rate obtained from the 5.5 liter effective volume counter for each year's sample is then referenced to a standard traceable to the National Bureau of Standards, and after corrections due to isotopic fracionation are applied, the ΔC-14 for each sample is determined. The fluctuations in the ΔC-14 are inspected, and used as an estimate for the energy content in the γ-ray burst of the Crab Nebula in 1054 A.D. Fluctuations due possibly to solar flares, neutron flux, cosmic ray muons, and sample preparation restrict the energy estimate to an upper limit of less than or equal to 10 50 ergs