WorldWideScience

Sample records for earlywood

  1. Force-displacement measurements of earlywood bordered pits using a mesomechanical tester.

    Science.gov (United States)

    Zelinka, Samuel L; Bourne, Keith J; Hermanson, John C; Glass, Samuel V; Costa, Adriana; Wiedenhoeft, Alex C

    2015-10-01

    The elastic properties of pit membranes are reported to have important implications in understanding air-seeding phenomena in gymnosperms, and pit aspiration plays a large role in wood technological applications such as wood drying and preservative treatment. Here we present force-displacement measurements for pit membranes of circular bordered pits, collected on a mesomechanical testing system. The system consists of a quartz microprobe attached to a microforce sensor that is positioned and advanced with a micromanipulator mounted on an inverted microscope. Membrane displacement is measured from digital image analysis. Unaspirated pits from earlywood of never-dried wood of Larix and Pinus and aspirated pits from earlywood of dried wood of Larix were tested to generate force-displacement curves up to the point of membrane failure. Two failure modes were observed: rupture or tearing of the pit membrane by the microprobe tip, and the stretching of the pit membrane until the torus was forced out of the pit chamber through the pit aperture without rupture, a condition we refer to as torus prolapse.

  2. Comparison of Dilute Acid and Sulfite Pretreatment for enzymatic Saccharification of Earlywood and Latewood of Douglas Fir

    Science.gov (United States)

    Chao Zhang; Xiaochun Lei; C. Tim Scott; J.Y. Zhu; Kecheng Li

    2014-01-01

    This study applied dilute acid (DA) and sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) to deconstruct earlywood and latewood cell walls of Douglas fir for fermentable sugars production through subsequent enzymatic hydrolysis. DA pretreatment removed almost all the hemicelluloses, while SPORL at initial pH=4.5 (SP-B) removed significant...

  3. Influence of chemical treatments on moisture-induced dimensional change and elastic modulus of earlywood and latewood

    Science.gov (United States)

    Robert J. Moon; Joseph Wells; David E. Kretschmann; James Evans; Alex C. Wiedenhoeft; Charles R. Frihart

    2010-01-01

    To better understand the performance of bonded, coated, and modified wood, knowledge of how these processes alter the dimensional change and mechanical properties of wood at a given moisture content (MC) are important. These localized influences on earlywood (EW) and latewood (LW) properties are not well understood. In the present study, the influence of chemical...

  4. A 481-year chronology of oak earlywood vessels as an age-independent climatic proxy in NW Iberia

    Science.gov (United States)

    Souto-Herrero, Manuel; Rozas, Vicente; García-González, Ignacio

    2017-08-01

    The earlywood vessels of ring-porous trees can be analyzed dendrochronologically and used as a proxy for environmental information. However, most works deal with the analysis of contemporary climate-growth relationships and do not evaluate their long-term variation. We obtained a 481-year chronology of earlywood vessel size of oak (Quercus robur L.) in the northwestern Iberian Peninsula, investigated its behavior through time, and compared it to a chronology of younger trees developed at the same site. We expressed earlywood vessel size as the hydraulically-weighted diameter (DH) and discriminated between vessels in the first row (r1) and the rest of the vessels (nr1); radial increment was assessed from latewood width (LW). Climate-growth relationships were strong and nearly identical for both age classes. Spring temperature positively affected vessel size, but only for the first row, probably mediating the onset of cambial activity. The chronology of old trees showed an almost flat age trend, except for the first decades, and series were not affected by stand dynamics. In contrast, LW had a weak response to climate, probably because of the high impact of abrupt growth changes. There was a high negative correlation between DH and the winter North Atlantic Oscillation Index (NAO), which was unstable during the 20th century. To our knowledge, this is the longest chronology of earlywood vessel size obtained to date, and offers promising results, as this proxy is shown to be independent of age and forest disturbances, and was strongly correlated to climate across long time spans.

  5. A 911 year chronology from earlywood vessels of European oak in NE-Germany and its use for climate reconstructions

    Science.gov (United States)

    Heinrich, Ingo; Balanzategui, Daniel; Heußner, Karl-Uwe; Pritzkow, Carola; Giese, Laura; Graaf, Johannes; Lindemann, Josephine; Schirmer, Thomas; Dorado Liñán, Isabel; Wazny, Tomasz; Scharnweber, Tobias; Van der Maaten, Ernst; Helle, Gerd; Blume, Theresa; Pohlmann, Silvio

    2016-04-01

    Tree-ring based temperature reconstructions form a substantial part of the international proxy data base used to examine and model global climate variations of the last Millennium. However, most tree-ring based reconstructions are derived from study sites in the high latitudes or high altitudes paying little attention to the temperate lowlands worldwide. Thus, a large gap in the geographical coverage of climate reconstructions, in particular temperature reconstructions, from temperate low elevation sites in central Europe still exists. This motivated us to concentrate our efforts on the European oak (Quercus robur) in Northeastern Germany, combining core samples from living trees with archaeological wood. We developed a new wood anatomical chronology focusing on the earlywood vessels of Q. robur for the period 1100 to 2011. As far as we know it is by far the longest chronology based on wood anatomical parameters. First climate growth analyses demonstrated that earlywood vessel parameters, especially average vessel area, contained climate signals which were different and more significant than those found in tree-ring widths. The strongest correlation was found with winter temperatures. This relationship was then used for a reconstruction for the period 1100 to 2011. By using only raw values, low-frequency signals could be sustained. This new reconstruction was compared with already existing temperature reconstructions and spatial field correlations were calculated. Results will be presented and discussed at EGU for the first time.

  6. Continuous earlywood vessels chronologies in floodplain ring-porous species can improve dendrohydrological reconstructions of spring high flows and flood levels

    Science.gov (United States)

    Kames, S.; Tardif, J. C.; Bergeron, Y.

    2016-03-01

    Plants respond to environmental stimuli through changes in growth and development. Characteristics of wood cells such as the cross-sectional area of vessel elements (hereafter referred to as vessels) may store information about environmental factors present at the time of vessel differentiation. The analysis of vessel characteristics therefore offers a different time resolution than annual ring width because vessels in tree rings differentiate within days to a few weeks. Little research has been conducted on the sensitivity of earlywood vessels in ring-porous species in response to flooding. The general objectives of this study were to determine the plasticity of earlywood vessel to high flows and spring flooding in floodplain black ash (Fraxinus nigra Marsh.) trees and to assess the utility of developing continuous earlywood vessel chronologies in dendrohydrological reconstruction. In contrast, most dendrohydrological studies until now have mainly used vessel anomalies (flood rings) as discrete variables to identify exceptional flood events. The study area is located in the boreal region of northwestern Québec. Vessel and ring-width chronologies were generated from F. nigra trees growing on the floodplain of Lake Duparquet. Spring discharge had among all hydro-climatic variables the strongest impact on vessel formation and this signal was coherent spatially and in the frequency domain. The mean vessel area chronology was significantly and negatively correlated to discharge and both the linearity and the strength of this association were unique. In floodplain F. nigra trees, spring flooding promoted the formation of more abundant but smaller earlywood vessels. Earlywood vessels chronologies were also significantly associated with other hydrological indicators like Lake Duparquet's ice break-up date and both ice-scar frequency and height chronologies. These significant relationships stress the utility of developing continuous vessels chronologies for hydrological

  7. Feedbacks between earlywood anatomy and non-structural carbohydrates affect spring phenology and wood production in ring-porous oaks

    Science.gov (United States)

    Pérez-de-Lis, Gonzalo; García-González, Ignacio; Rozas, Vicente; Olano, José Miguel

    2016-10-01

    Non-structural carbohydrates (NSC) play a central role in the construction and maintenance of a tree's vascular system, but feedbacks between the NSC status of trees and wood formation are not fully understood. We aimed to evaluate multiple dependencies among wood anatomy, winter NSC, and phenology for coexisting temperate (Quercus robur) and sub-Mediterranean (Q. pyrenaica) oaks along a water-availability gradient in the NW Iberian Peninsula. Sapwood NSC concentrations were quantified at three sites in December 2012 (N = 240). Leaf phenology and wood anatomy were surveyed in 2013. Structural equation modelling was used to analyse the interplay among hydraulic diameter (Dh), winter NSC, budburst date, and earlywood vessel production (EVP), while the effect of Dh and EVP on latewood width was assessed by using a mixed-effects model. NSC and wood production increased under drier conditions for both species. Q. robur showed a narrower Dh and lower soluble sugar (SS) concentration (3.88-5.08 % dry matter) than Q. pyrenaica (4.06-5.57 % dry matter), but Q. robur exhibited larger EVP and wider latewood (1403 µm) than Q. pyrenaica (667 µm). Stem diameter and Dh had a positive effect on SS concentrations, which were related to an earlier leaf flushing in both species. Sapwood sugar content appeared to limit EVP exclusively in Q. pyrenaica. In turn, Dh and EVP were found to be key predictors of latewood growth. Our results confirm that sapwood SS concentrations are involved in modulating growth resumption and xylem production in spring. Q. pyrenaica exhibited a tighter control of carbohydrate allocation to wood formation than Q. robur, which would play a role in protecting against environmental stress in the sub-Mediterranean area.

  8. 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.

  9. Effect of growth ring orientation and placement of earlywood and latewood on MOE and MOR of very-small clear Douglas-fir beams.

    Science.gov (United States)

    Amy T. Grotta; Robert J. Leichti; Barbara L. Gartner; G.R. Johnson

    2005-01-01

    ASTM standard sizes for bending tests (either 50 x 50 mm or 25 x 25 mm in cross-section) are not always suitable for research purposes that characterize smaller sections of wood. Moreover, the ASTM standards specify loading the sample on the longitudinal-tangential surface. If specimens are small enough, then the effects of both growth-ring orientation and whether...

  10. Microtensile strength of spruce pine after exposure to acids and bases

    Science.gov (United States)

    Floyd G. Manwiller; Paul R. Godfrey

    1972-01-01

    Earlywood and latewood microtensile specimens from 12 trees of Pinus glabra Wal. were subjected to 10-percent solution of 5 acids and 3 bases at 90oC for up to 3 hours. Hydrochloric and sulfuric acids were the most damaging, lowering maximum tensile strength 27 and 17 percent in earlywood and 36 and 39 percent in latewood; they...

  11. Xylem Development of Loblolly Pine During Irrigation and Simulated Drought

    Science.gov (United States)

    David M. Moehring; Charles X. Grano; John R. Bassett

    1975-01-01

    Induced drought decreased the total number of tracheid cells produced in a season and the radial width of late wood tracheids. Transition from earlywood to late woodo ccurred in early June and was little affected by irrigation.

  12. Annual cyclicity in high-resolution stable carbon and oxygen isotope ratios in the wood of the mangrove tree Rhizophora mucronata

    OpenAIRE

    Verheyden, A.; Gerhard Helle; G. H. Schleser; F. Dehairs; BEECKMAN, H.; Koedam, N.;  

    2004-01-01

    In the present study, the high-resolution stable carbon (13C/12C) and oxygen (18O/16O) isotope ratio profiles in the wood of the mangrove Rhizophora mucronata Lam., a tropical tree species lacking distinct growth rings, were investigated. Variations of both isotope ratios revealed a remarkable annual cyclicity with lowest values occurring at the latewood/earlywood boundary (April–May) and highest values during the transition from earlywood to latewood (October–November). Based on the current ...

  13. Annual cyclicity in high-resolution stable carbon and oxygen isotope ratios in the wood of the mangrove tree Rhizophora mucronata

    OpenAIRE

    Verheyden, A.; Helle, G.; G. H. Schleser; F. Dehairs; BEECKMAN, H.; Koedam, N.

    2004-01-01

    In the present study, the high-resolution stable carbon ((13)C/(12)C) and oxygen ((18)O/(16)O) isotope ratio profiles in the wood of the mangrove Rhizophora mucronata Lam., a tropical tree species lacking distinct growth rings, were investigated. Variations of both isotope ratios revealed a remarkable annual cyclicity with lowest values occurring at the latewood/earlywood boundary (April-May) and highest values during the transition from earlywood to latewood (October-November). Based on the ...

  14. Surface energy of preservative-treated southern yellow pine (Pinus spp.) by contact angle measurement

    Institute of Scientific and Technical Information of China (English)

    CAO Jinzhen; Pascal D.Kamdem

    2007-01-01

    In this study,the contact angles of four different reference liquids (including distilled water,diiodomethane,formadide and glycerol) formed on the surfaces of wood,treated with chromated copper arsenate (CCA) and two other emerging copper-based water-borne systems (commercial names:NW and NS) were measured with sessile drop method.Based on the contact angle data,the surface energy was obtained from the acid-base approach.The total surface energy consisted of Lifshiz-van der Waals parameter and acid-base parameter.Results showed that the NW and CCA treatments made the wood surface more hydrophobic while the NS treatment had the reverse effect on the wood surface mainly owing to the increased penetration of earlywood.By using three liquids,diiodomethane,formamide and distilled water,the total surface energy obtained for untreated earlywood,untreated latewood, CCA-treated earlywood,CCA-treated latewood,NW-treated earlywood,NW-treated latewood,NS-treated earlywood and NS-treated latewood were 43.1,44.5,43.4,45.1,49.4,40.6,46.0 and 40.9 mJ/m2,respectively.The surface energy of CCA-treated wood was almost the same as untreated wood.After NW and NS treatments,the surface energy of both earlywood and latewood changed a little.However,the change was not so obvious as to draw any further conclusion concerning the influence of NW and NS treatments on the surface energy of wood.

  15. 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

  16. Transcriptome profiling of Pinus radiata juvenile wood with contrasting stiffness identifies putative candidate genes involved in microfibril orientation and cell wall mechanics

    Directory of Open Access Journals (Sweden)

    Wu Harry X

    2011-10-01

    Full Text Available Abstract Background The mechanical properties of wood are largely determined by the orientation of cellulose microfibrils in secondary cell walls. Several genes and their allelic variants have previously been found to affect microfibril angle (MFA and wood stiffness; however, the molecular mechanisms controlling microfibril orientation and mechanical strength are largely uncharacterised. In the present study, cDNA microarrays were used to compare gene expression in developing xylem with contrasting stiffness and MFA in juvenile Pinus radiata trees in order to gain further insights into the molecular mechanisms underlying microfibril orientation and cell wall mechanics. Results Juvenile radiata pine trees with higher stiffness (HS had lower MFA in the earlywood and latewood of each ring compared to low stiffness (LS trees. Approximately 3.4 to 14.5% out of 3, 320 xylem unigenes on cDNA microarrays were differentially regulated in juvenile wood with contrasting stiffness and MFA. Greater variation in MFA and stiffness was observed in earlywood compared to latewood, suggesting earlywood contributes most to differences in stiffness; however, 3-4 times more genes were differentially regulated in latewood than in earlywood. A total of 108 xylem unigenes were differentially regulated in juvenile wood with HS and LS in at least two seasons, including 43 unigenes with unknown functions. Many genes involved in cytoskeleton development and secondary wall formation (cellulose and lignin biosynthesis were preferentially transcribed in wood with HS and low MFA. In contrast, several genes involved in cell division and primary wall synthesis were more abundantly transcribed in LS wood with high MFA. Conclusions Microarray expression profiles in Pinus radiata juvenile wood with contrasting stiffness has shed more light on the transcriptional control of microfibril orientation and the mechanical properties of wood. The identified candidate genes provide an

  17. [Dendrochronology of Chinese pine in Mulan-Weichang, Hebei Province: a primary study].

    Science.gov (United States)

    Cui, Ming-xing; He, Xing-yuan; Chen, Wei; Chen, Zhen-ju; Zhou, Chang-hong; Wu, Tao

    2008-11-01

    Dendroclimatic methods were used to investigate the relationships between the growth of Chinese pine (Pinus tabulaeformis Carr.) and the climatic parameters in Mulan-Weichang of Hebei Province. The results showed that Chinese pine presented high sensitivity to climatic changes, and its earlywood width showed the highest sensitivity. There was a significant negative correlation between the tree-ring width chronology of Chinese pine and the air temperature in May-June. The precipitation and relative humidity in June had strong positive effects on the growth of earlywood, the precipitation from September to next September had significant positive effects on Chinese pine growth, and the relative humidity in winter more strongly affected the growth of latewood than of earlywood. There was a definite correlation between the tree-ring width chronology of Chinese pine and the large scale climate fluctuation. From 1951 to 2006, the increase of air temperature in study area was significant, and the sensitivity of Chinese pine to the variations of local temperature and precipitation decreased, presenting an inverse transforming trend with increasing temperature. Greater differences were observed between the reconstructed and observed data of mean temperature in May - June in a century scale, suggesting that the tree-ring growth of Chinese pine in study area had a greater fluctuation of sensitivity to the variation of climatic factors.

  18. Duration and extension of anatomical changes in wood structure after cambial injury.

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    Arbellay, Estelle; Fonti, Patrick; Stoffel, Markus

    2012-05-01

    Cambial injury has been reported to alter wood structure in broad-leaved trees. However, the duration and extension of associated anatomical changes have rarely been analysed thoroughly. A total of 18 young European ash (Fraxinus excelsior L.) trees injured on the stem by a spring flood were sampled with the aim of comparing earlywood vessels and rays formed prior to and after the scarring event. Anatomical and hydraulic parameters were measured in five successive rings over one-quarter of the stem circumference. The results demonstrate that mechanical damage induces a decrease in vessel lumen size (up to 77%) and an increase in vessel number (up to 475%) and ray number (up to 115%). The presence of more earlywood vessels and rays was observed over at least three years after stem scarring. By contrast, abnormally narrow earlywood vessels mainly developed in the first ring formed after the event, increasing the thickness-to-span ratio of vessels by 94% and reducing both xylem relative conductivity and the index for xylem vulnerability to cavitation by 54% and 32%, respectively. These vessels accumulated in radial groups in a 30° sector immediately adjacent to the wound, raising the vessel grouping index by 28%. The wound-induced anatomical changes in wood structure express the functional need of trees to improve xylem hydraulic safety and mechanical strength at the expense of water transport. Xylem hydraulic efficiency was restored in one year, while xylem mechanical reinforcement and resistance to cavitation and decay lasted over several years.

  19. False ring formation in eastern hemlock branches: impacts of hemlock woolly adelgid and elongate hemlock scale.

    Science.gov (United States)

    Gonda-King, Liahna; Radville, Laura; Preisser, Evan L

    2012-06-01

    Herbivores can alter plant physiology through the induction of abnormal wood formation. Feeding by some insects induces the formation of false rings, a band of thick-walled latewood cells within the earlywood portion of the tree ring that reduces water transport. Hemlock woolly adelgid (Adelges tsugae Annand) and elongate hemlock scale (Fiorinia externa Ferris) are invasive insects that both feed on eastern hemlock [Tsuga canadensis (L.) Carrière]. Adelges tsugae has a greater effect on tree health than F. externa, but the mechanism underlying their differential effect is unknown. We explored the effects of these herbivores by assessing growth ring formation in branches of trees that had been experimentally infested for 4 yr with A. tsugae, F. externa, or neither insect. We measured false ring density, ring growth, and earlywood: latewood ratios in the two most recently deposited growth rings. Branches from A. tsugae-infested trees had 30% more false rings than branches from F. externa-infested trees and 50% more than branches from uninfested trees. In contrast, branches from F. externa-infested trees and control trees did not differ in false ring formation. Radial growth and earlywood: latewood ratios did not differ among treatments. Our results show that two invasive herbivores with piercing-sucking mouth parts have differing effects on false ring formation in eastern hemlock. These false rings may be the product of a systemic plant hypersensitive response to feeding by A. tsugae on hemlock stems. If false rings are responsible for or symptomatic of hemlock water stress, this may provide a potential explanation for the relatively large effect of A. tsugae infestations on tree health.

  20. Water sorption in wood and modified wood at high values of relative humidity

    DEFF Research Database (Denmark)

    Engelund, Emil Tang; Thygesen, Lisbeth Garbrecht; Hoffmeyer, Preben

    2010-01-01

    A theoretical study of the amount of moisture held in wood as capillary condensed water in the relative humidity (RH) range of 90–99.9% is carried out. The study is based on idealized geometries of the softwood structure related to micrographs. It is confined to structural elements such as bordered...... pits and the pointed ends of tracheids. The theoretical amount of water in these elements is found by employing the Kelvin equation. An equal amount of earlywood and latewood cells with different geometries and with different amounts of pits is assumed. The effect of pit aspiration is considered...

  1. Response of Pinus sylvestris roots to sheet-erosion exposure: an anatomical approach

    Science.gov (United States)

    Rubiales, J. M.; Bodoque, J. M.; Ballesteros, J. A.; Diez-Herrero, A.

    2008-03-01

    Anatomical changes of exposed tree roots are valuable tools to date erosion events, but the responses of diverse species under different types of erosion need still to be studied in detail. In this paper we analyze the histological changes that occur in roots of Scots pine (Pinus sylvestris L.) subjected to continuous denudation. A descriptive and quantitative study was conducted in the Senda Schmidt, a popular trail located on the northern slope of the Sierra de Guadarrama (Central Iberian System, Spain). Measurement of significant parameters allowed the moment of exposure of the roots to be identified. These parameters were: a) width of the growth ring; b) number of cells per ring; c) percentage of latewood and d) diameter of cellular light in earlywood. A one-way analysis ANOVA was also carried out in order to establish statistically significant differences between homogeneous groups of measurements in pre-exposed and exposed roots. Based on these analyses, Scots pine roots show a remarkable anatomical response to sheet-erosion exposure. Increased growth in the ring is accompanied by a slight reduction of the cell lumina of the earlywood tracheids. At the end of the ring, several rows of thick-walled tracheids define latewood tissue and visible annual borders very clearly. Furthermore, resin ducts often appear in tangential rows, increasing resin density in the tissue. All of these indicators made it possible to determine with precision the first year of exposure and to estimate precisely sheet erosion rates.

  2. Severe winter rings of oak trees (Quercus robur L.) from Central European Russia.

    Science.gov (United States)

    Khasanov, B F

    2013-11-01

    Oak trees were sampled in a flood plain forest in the valley of the Zapadnaya Dvina (Daugava) river (Tver region, Russia). Annual rings of the time period from 1826 to 2010 were studied. Anatomically distinct rings with a stripe of small-sized cells in the innermost part and narrow earlywood vessels located in three to four rows occurred in 1861, 1862, 1929, 1940, 1942, 1956 and 1979. Deviations of earlywood development were associated with the drop of winter temperature below -42 °C. The percentage of severe winter ring (SWR) occurrence depends upon tree age and decreases from 75.6 % in younger specimens (under 41 years old at the time of the severe winter) to 27.1 % in middle-aged ones (from 41 to 80 years) to 3.5 % in trees older than 80 years. Described anatomical features can be used in the reconstruction of severe winter frequency in the past.

  3. Reconstruction of May-July precipitation in the north Helan Mountain, Inner Mongolia since A.D.1726 from tree-ring late-wood widths

    Institute of Scientific and Technical Information of China (English)

    LIU Yu; SHI Jiangfeng; V. Shishov; E. Vaganov; YANG Yinke; CAI Qiufang; SUN Junyan; WANG Lei; I. Djanseitov

    2004-01-01

    By analyzing statistical characteristics of five tree-ring standard chronologies, early-wood ring width (EWW), late-wood ring width (LWW), total ring width (TRW), minimum early-wood density (MinD), maximum late-wood density (MaxD) and, their climatic response respectively, we reconstructed the May to July precipitation using late-wood ring width (LWW) over the north Helan Mountain since A.D. 1726. The explained variance is 42% (R2adj = 41%, F = 31.46, p < 0.000001). After 11-a moving average, the explained variance reaches 82% (F = 156.9, p < 0.05). On the decadal scale, the rainfall reconstruction of the northern Helan Mountain displays a quite similar variation pattern with that of the April to early July precipitation in Baiyinaobao, east of Inner Mongolia for the last 150 years. It may reflect the intensity variation of the East Asia Summer Monsoon front to a certain extent. Spectrum analysis shows 11-a and 22-a periodicities in the May to July precipitation reconstruction at the north Helan Mountain.

  4. Climatic Influences on Wood Anatomy and Tree-Ring Features of Great Basin Conifers at a New Mountain Observatory

    Directory of Open Access Journals (Sweden)

    Emanuele Ziaco

    2014-10-01

    Full Text Available Premise of the study: A network of mountain observing stations has been installed in the Great Basin of North America. NevCAN (Nevada Climate-ecohydrological Assessment Network, which spans a latitudinal range of 2.5° and two elevation ranges of about 2000 m each, enabled us to investigate tree growth in relation to climate. Methods: We analyzed wood anatomy and tree-ring characteristics of four conifer species in response to different levels of water availability by comparing a low- and a high-elevation population. Chronologies of earlywood and latewood widths, as well as cellular parameters, were developed from the year 2000 to 2012. Results: At the southern (drier and warmer sites, Pinus monophylla had smaller cell lumen, tracheid diameter, and cell wall thickness. Pinus monophylla and P. flexilis showed bigger cellular elements at the higher elevations, whereas the opposite pattern was found in Picea engelmannii and Pinus longaeva. When all species and sites were pooled together, stem diameter was positively related with earlywood anatomical parameters. Discussion: We have provided a glimpse of the applications that NevCAN, as a new scientific tool, could allow in the general field of botany. In particular, we were able to investigate how differences in water stress related to elevation lead to changes in xylem anatomy.

  5. SAFETY FACTORS FOR XYLEM FAILURE BY IMPLOSION AND AIR-SEEDING WITHIN ROOTS, TRUNKS AND BRANCHES OF YOUNG AND OLD CONIFER TREES

    Energy Technology Data Exchange (ETDEWEB)

    Domec, Jean-Christophe [North Carolina State University; Warren, Jeffrey M. [Oak Ridge National Laboratory (ORNL); Meinzer, Rick [USDA Forest Service; Lachenbruch, Barbara [Oregon State University, Corvallis

    2009-01-01

    The cohesion-tension theory of water transport states that hydrogen bonds hold water molecules together and that they are pulled through the xylem under tension. This tension could cause transport failure in at least two ways: collapse of the conduit walls (implosion), or rupture of the water column through air-seeding. The objective of this research was to elucidate the functional significance of variations in tracheid anatomical features, earlywood to latewood ratios and wood densities with position in young and old Douglas-fir and ponderosa pine trees in terms of their consequences for the safety factors for tracheid implosion and air-seeding. For both species, wood density increased linearly with percent latewood for root, trunk and branch samples. However, the relationships between anatomy and hydraulic function in trunks differed from those in roots and branches. In roots and branches increased hydraulic efficiency was achieved at the cost of increased vulnerability to air-seeding. Mature wood of trunks had earlywood with wide tracheids that optimized water transport and had a high percentage of latewood that optimized structural support. Juvenile wood had higher resistance to air-seeding and cell wall implosion. The two safety factors followed similar axial trends from roots to terminal branches and were similar for both species studied and between juvenile and mature wood.

  6. Response of anatomical structures in tree roots to an erosion event on the southeastern Tibetan Plateau

    Science.gov (United States)

    Sun, Liping; Wang, Xiaodan; Hong, Jiangtao

    2014-01-01

    Exposed roots have been used in dendrogeomorphology to determine erosion rates. However, few studies have focused on the changes in ring width and in the anatomical properties of hardwood roots exposed by soil erosion at a macroscopic and microscopic level. In this study, we identified the ring width and the anatomical response of hardwood root to a denudation event and applied these anatomical findings to the reconstruction and quantification of soil erosion rates. A total of 136 cross sections (54 from buried roots and 79 from exposed roots of 25 trees) were sampled in the study area. Measurements of the widths of the growth rings, the average vessel area in earlywood, the average vessel area per ring, and the vessel number per ring were performed with WinDENDRO and ImageJ. Our results show that the analysis of vessel features is a useful tool to identify soil erosion events recorded during the life of a tree. A sharp decrease of nearly 50% in the vessel area of earlywood was an important signature indicating the exposure of tree roots caused by denudation. Soil erosion rates derived from exposed roots varied between 1.04 and 3.61 mm y- 1 in the southeastern Tibetan Plateau.

  7. Generation and analysis of expressed sequence tags from six developing xylem libraries in Pinus radiata D. Don

    Directory of Open Access Journals (Sweden)

    Dillon Shannon K

    2009-01-01

    Full Text Available Abstract Background Wood is a major renewable natural resource for the timber, fibre and bioenergy industry. Pinus radiata D. Don is the most important commercial plantation tree species in Australia and several other countries; however, genomic resources for this species are very limited in public databases. Our primary objective was to sequence a large number of expressed sequence tags (ESTs from genes involved in wood formation in radiata pine. Results Six developing xylem cDNA libraries were constructed from earlywood and latewood tissues sampled at juvenile (7 yrs, transition (11 yrs and mature (30 yrs ages, respectively. These xylem tissues represent six typical development stages in a rotation period of radiata pine. A total of 6,389 high quality ESTs were collected from 5,952 cDNA clones. Assembly of 5,952 ESTs from 5' end sequences generated 3,304 unigenes including 952 contigs and 2,352 singletons. About 97.0% of the 5,952 ESTs and 96.1% of the unigenes have matches in the UniProt and TIGR databases. Of the 3,174 unigenes with matches, 42.9% were not assigned GO (Gene Ontology terms and their functions are unknown or unclassified. More than half (52.1% of the 5,952 ESTs have matches in the Pfam database and represent 772 known protein families. About 18.0% of the 5,952 ESTs matched cell wall related genes in the MAIZEWALL database, representing all 18 categories, 91 of all 174 families and possibly 557 genes. Fifteen cell wall-related genes are ranked in the 30 most abundant genes, including CesA, tubulin, AGP, SAMS, actin, laccase, CCoAMT, MetE, phytocyanin, pectate lyase, cellulase, SuSy, expansin, chitinase and UDP-glucose dehydrogenase. Based on the PlantTFDB database 41 of the 64 transcription factor families in the poplar genome were identified as being involved in radiata pine wood formation. Comparative analysis of GO term abundance revealed a distinct transcriptome in juvenile earlywood formation compared to other stages of

  8. Effects of Invasive Winter Moth Defoliation on Tree Radial Growth in Eastern Massachusetts, USA

    Science.gov (United States)

    Simmons, Michael J.; Lee, Thomas D.; Ducey, Mark J.; Elkinton, Joseph S.; Boettner, George H.; Dodds, Kevin J.

    2014-01-01

    Winter moth, Operophtera brumata L. (Lepidoptera: Geometridae), has been defoliating hardwood trees in eastern Massachusetts since the 1990s. Native to Europe, winter moth has also been detected in Rhode Island, Connecticut, eastern Long Island (NY), New Hampshire, and Maine. Individual tree impacts of winter moth defoliation in New England are currently unknown. Using dendroecological techniques, this study related annual radial growth of individual host (Quercus spp. and Acer spp.) trees to detailed defoliation estimates. Winter moth defoliation was associated with up to a 47% reduction in annual radial growth of Quercus trees. Latewood production of Quercus was reduced by up to 67% in the same year as defoliation, while earlywood production was reduced by up to 24% in the year following defoliation. Winter moth defoliation was not a strong predictor of radial growth in Acer species. This study is the first to document impacts of novel invasions of winter moth into New England. PMID:26462685

  9. Effects of Invasive Winter Moth Defoliation on Tree Radial Growth in Eastern Massachusetts, USA

    Directory of Open Access Journals (Sweden)

    Michael J. Simmons

    2014-04-01

    Full Text Available Winter moth, Operophtera brumata L. (Lepidoptera: Geometridae, has been defoliating hardwood trees in eastern Massachusetts since the 1990s. Native to Europe, winter moth has also been detected in Rhode Island, Connecticut, eastern Long Island (NY, New Hampshire, and Maine. Individual tree impacts of winter moth defoliation in New England are currently unknown. Using dendroecological techniques, this study related annual radial growth of individual host (Quercus spp. and Acer spp. trees to detailed defoliation estimates. Winter moth defoliation was associated with up to a 47% reduction in annual radial growth of Quercus trees. Latewood production of Quercus was reduced by up to 67% in the same year as defoliation, while earlywood production was reduced by up to 24% in the year following defoliation. Winter moth defoliation was not a strong predictor of radial growth in Acer species. This study is the first to document impacts of novel invasions of winter moth into New England.

  10. 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.

  11. Răspunsul comparativ al fagului şi stejarului la secetă în Rezervaţia Naturală Codrii (R. Moldova [Comparative response of beech and oak to drought in Codrii Natural Reserve (R. Moldova

    Directory of Open Access Journals (Sweden)

    Popa Ionel

    2015-08-01

    Full Text Available Drought is main climatic risk factor in Republic of Moldova with major effects on economic and ecologic level. Regional climatic models indicate for Moldova an increase of temperature and decrease of precipitation during the summer in the future decades. We evaluated the response of beech and oak to cumulative water deficit using SPEI index at different time scales. Results of climate-growth correlations indicate a higher sensitivity of beech to drought comparing with oak. Maximum correlation for beech is observed at 18-20 month SPEI scale (0.60 and for oak at time scale of 12-18 month, but lower (0.45. Earlywood growth index of oak are low correlated with SPEI. Oak, a more tolerant drought species, is more adapted compared with beech under the forescasted climatic changes in this region.

  12. [Analysis of cell arrangements in Biota orientalis using Fourier transformation].

    Science.gov (United States)

    Duo, Hua-Qiong; Wang, Xi-Ming

    2009-10-01

    Fourier transform image-processing technology is applied for determining the cross section cell arrangement of early-wood in Biota orientalis. In this method, the disc-convoluted dot map from each cell radius with 10 pixels is transformed by Fourier transform, generating the angle distribution function in the power spectral pattern. The maximum value is the arrangement of the cell. The results of Fourier transform image-processing technology indicated that the arrangements of the cell of Biota orientalis are 15 degrees in oblique direction, respectively. This method provides a new basis for the digitized identification of the wood, and also the new theoretical research direction for the digitized identification and examination of the wood species.

  13. Dendroclimatic signals deduced from riparian versus upland forest interior pines in North Karelia, Finland

    DEFF Research Database (Denmark)

    Helama, Samuli; Arentoft, Birgitte W.; Collin-Haubensak, Olivier

    2013-01-01

    Radial growth of boreal tree species is only rarely studied in riparian habitats. Here we investigated chronologies of earlywood, latewood, and annual ring widths and blue intensity (BI; a surrogate to latewood density) from riparian lake shore and upland forest interior pines (Pinus sylvestris L...... with the tree-ring chronologies were related to snow conditions at the start of the growing season. Deeper snowpack led to reduced upland pine growth, possibly due to delayed snowmelt and thus postponed onset of the growing season. Warm late winters were followed by increased riparian pine growth because...... a strong correlation with warm-season temperatures, indicating an encouraging possibility of summer temperature reconstruction using middle/south boreal pine tree-ring archives....

  14. 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

  15. Aspirated pits in wetwood and micromorphology of microbial degradation in subalpine fir

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yaoli; CAI Liping; XU Yongji

    2006-01-01

    Differentiating from normal wood,pit membranes in wetwood of subalpine fir contain bacteria of water drop shape or orbicular shape,and flaky shape,as observed using Scanning Electronic Microscope.Not only are ray parenchyma cells in wetwood partially degraded but also margo strands in pit membranes are somewhat degraded by bacterial activities.Most of the bordered-pit membranes in normal wood are unaspirated in green conditions and the proportions of aspirated pits in earlywood and latewood account for only 6.8% and 13.4%,respectively.Nevertheless,most of the bordered-pit membranes in wetwood are aspirated in green conditions and the proportions of aspirated pits account for 77.7% and 72.1%,respectively.The problem of hard-to-dry for subalpine fir could be reasoned from the considerable amount of aspirated pit membranes in wetwood.

  16. {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.

  17. Chronological Sequence of Leaf Phenology, Xylem and Phloem Formation and Sap Flow of Quercus pubescens from Abandoned Karst Grasslands.

    Science.gov (United States)

    Lavrič, Martina; Eler, Klemen; Ferlan, Mitja; Vodnik, Dominik; Gričar, Jožica

    2017-01-01

    Intra-annual variations in leaf development, radial growth, including the phloem part, and sap flow have rarely been studied in deciduous trees from drought-prone environments. In order to understand better the chronological order and temporal course of these processes, we monitored leaf phenology, xylem and phloem formation and sap flow in Quercus pubescens from abandoned karst grasslands in Slovenia during the growing season of 2014. We found that the initial earlywood vessel formation started before bud opening at the beginning of April. Buds started to open in the second half of April and full leaf unfolding occurred by the end of May. LAI values increased correspondingly with leaf development. About 28% of xylem and 22% of phloem annual increment were formed by the time of bud break. Initial earlywood vessels were fully lignified and ready for water transport, indicating that they are essential to provide hydraulic conductivity for axial water flow during leaf development. Sap flow became active and increasing contemporarily with leaf development and LAI values. Similar early spring patterns of xylem sap flow and LAI denoted that water transport in oaks broadly followed canopy leaf area development. In the initial 3 weeks of radial growth, phloem growth preceded that of xylem, indicating its priority over xylem at the beginning of the growing season. This may be related to the fact that after bud break, the developing foliage is a very large sink for carbohydrates but, at the same time, represents a small transpirational area. Whether the interdependence of the chronological sequence of the studied processes is fixed in Q. pubescens needs to be confirmed with more data and several years of analyses, although the 'correct sequence' of processes is essential for synchronized plant performance and response to environmental stress.

  18. The changes in redox status of ascorbate in stem tissue cells during Scots pine tree growth

    Directory of Open Access Journals (Sweden)

    G. F. Antonova

    2017-02-01

    Full Text Available The contents of ascorbate (AsA and dehydroascorbate (DHA and their ratio, showing cellular redox state of AsA, were studied in the cells of the separate tissues at different levels of Pinus sylvestris L. stem during early- and latewood formation. Morphological status of the cells in the tissues and the content of soluble carbohydrates were also estimated. The cellular redox potential of AsA has been found to depend on the type of tissue, cell development degree, the level of stem and the type of forming wood. The content of AsA and AsA/DHA ratio in the cells of non-conducting phloem along the stem were higher than in mature xylem and less during earlywood than latewood formation. The cells of conducting phloem and forming xylem, as the principal tissues taking part in annual ring wood formation, differed in the content of acids in the course of early and late xylem formation. Along the stem, the content of AsA decreased in conducting phloem cells and increased in the cells of forming xylem during both early- and latewood formation. The AsA/DHA of conducting phloem during earlywood formation was greatest below the stem and diminished to the top of the tree, while in the course of latewood development it was similar at all levels. In forming xylem AsA/DHA increased to the top of tree during the early xylem formation and decreased in late xylem that indicates the differences in oxidation-reduction reactions into the cells of two type of forming wood. The data are discussed according to morphological development of cells and the content of carbohydrates.

  19. Chronological Sequence of Leaf Phenology, Xylem and Phloem Formation and Sap Flow of Quercus pubescens from Abandoned Karst Grasslands

    Science.gov (United States)

    Lavrič, Martina; Eler, Klemen; Ferlan, Mitja; Vodnik, Dominik; Gričar, Jožica

    2017-01-01

    Intra-annual variations in leaf development, radial growth, including the phloem part, and sap flow have rarely been studied in deciduous trees from drought-prone environments. In order to understand better the chronological order and temporal course of these processes, we monitored leaf phenology, xylem and phloem formation and sap flow in Quercus pubescens from abandoned karst grasslands in Slovenia during the growing season of 2014. We found that the initial earlywood vessel formation started before bud opening at the beginning of April. Buds started to open in the second half of April and full leaf unfolding occurred by the end of May. LAI values increased correspondingly with leaf development. About 28% of xylem and 22% of phloem annual increment were formed by the time of bud break. Initial earlywood vessels were fully lignified and ready for water transport, indicating that they are essential to provide hydraulic conductivity for axial water flow during leaf development. Sap flow became active and increasing contemporarily with leaf development and LAI values. Similar early spring patterns of xylem sap flow and LAI denoted that water transport in oaks broadly followed canopy leaf area development. In the initial 3 weeks of radial growth, phloem growth preceded that of xylem, indicating its priority over xylem at the beginning of the growing season. This may be related to the fact that after bud break, the developing foliage is a very large sink for carbohydrates but, at the same time, represents a small transpirational area. Whether the interdependence of the chronological sequence of the studied processes is fixed in Q. pubescens needs to be confirmed with more data and several years of analyses, although the ‘correct sequence’ of processes is essential for synchronized plant performance and response to environmental stress. PMID:28321232

  20. Can forest dieback and tree death be predicted by prior changes in wood anatomy?

    Science.gov (United States)

    Colangelo, Michele; Julio Camarero, Jesus; De Micco, Veronica; Borghetti, Marco; Gentilesca, Tiziana; Sanchez-Salguero, Raul; Ripullone, Francesco

    2017-04-01

    Climate warming is expected to amplify drought stress resulting in more intense and widespread dieback episodes and increasing mortality rates. Studies on quantitative wood anatomy and dendrochronology have demonstrated their potential to supply useful information on the causes of tree decline, although this approach is basically observational and retrospective. Moreover, the long-term reconstruction of wood anatomical features, strictly linked to the evolution of xylem anatomy plasticity through time, allow investigating hydraulic adjustments of trees. In this study, we analyzed wood-anatomical variables in two Italian oak forests where recent episodes of dieback and mortality have been reported. We analyzed in coexisting now-dead and living trees the following wood-anatomical variables: annual tree-ring area, earlywood (EW) and latewood (LW) areas, absolute and relative (%) areas occupied by vessels in the EW and LW, EW and LW vessel areas, EW and LW vessel density and vessel diameter classification. We also calculated the hydraulic diameter (Dh) for all vessels measured within each ring by weighting individual conduit diameters to correspond to the average Hagen-Poiseuille lumen theoretical hydraulic conductivity for a vessel size. Wood-anatomical analyses showed that declining and dead trees were more sensitive to drought stress compared to non declining trees, indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. We discuss the results and implications focusing on those proved more sensitive to the phenomena of decline and mortality.

  1. Evidence of floods on the Potomac River from anatomical abnormalities in the wood of flood-plain trees

    Science.gov (United States)

    Yanosky, Thomas M.

    1983-01-01

    Ash trees along the Potomac River flood plain near Washington, D.C., were studied to determine changes in wood anatomy related to flood damage, and anomalous growth was compared to flood records for April 15 to August 31, 1930-79. Collectively, anatomical evidence was detected for 33 of the 34 growing-season floods during the study period. Evidence of 12 floods prior to 1930 was also noted, including catastrophic ones in 1889 and 1924. Trees damaged after the transition from earlywood to latewood growth typically formed ' flood rings ' of enlarged vessels within the latewood zone. Trees damaged near the beginning of the growth year developed flood rings within, or contiguous with, the earlywood. Both patterns are assumed to have developed when flood-damaged trees produced a second crop of leaves. Trees damaged by high-magnitude floods developed well formed flood rings along the entire height and around the entire circumference of the stem. Small floods were generally associated wtih diffuse or discontinuous anomalies restricted to stem apices. Frequency of flood rings was positively related to flood magnitude, and time of flood generation during the tree-growth season was estimated from the radial position of anomalous growth relative to annual ring width. Reconstructing tree heights in a year of flood-ring formation gives a minimum stage estimate along local stream reaches. Some trees provided evidence of numerous floods. Those with the greatest number of flood rings grew on frequently flooded surfaces subject to flood-flow velocities of at least 1 m/s, and more typically greater than 2 m/s. Tree size, more than age, was related to flood-ring formation. Trees kept small by frequent flood damage had more flood rings than taller trees of comparable age. (USGS)

  2. CLIMATIC SIGNALS FROM INTRA-ANNUAL DENSITY FLUCTUATION FREQUENCY IN MEDITERRANEAN PINES AT A REGIONAL SCALE

    Directory of Open Access Journals (Sweden)

    Enrica eZalloni

    2016-05-01

    Full Text Available Tree rings provide information about the climatic conditions during the growing season by recording them in different anatomical features, such as Intra-Annual Density Fluctuations (IADFs. IADFs are intra-annual changes of wood density appearing as latewood-like cells within earlywood, or earlywood-like cells within latewood. The occurrence of IADFs is dependent on the age and size of the tree, and it is triggered by climatic drivers. The variations of IADF frequency of different species and their dependence on climate across a wide geographical range have still to be explored. The objective of this study is to investigate the effect of age, tree-ring width and climate on IADF formation and frequency at a regional scale across the Mediterranean Basin in Pinus halepensis Mill., Pinus pinaster Ait. and Pinus pinea L. The analyzed tree-ring network was composed of P. pinea trees growing at 11 sites (2 in Italy, 4 in Spain and 4 in Portugal, P. pinaster from 19 sites (2 in Italy, 13 in Spain and 4 in Portugal, and P. halepensis from 38 sites in Spain. The correlations between IADF frequency and monthly minimum, mean and maximum temperatures, as well as between IADF frequency and total precipitation, were analyzed. A significant negative relationship between IADF frequency and tree-ring age was found for the three Mediterranean pines. Moreover, IADFs were more frequent in wider rings than in narrower ones, although the widest rings showed a reduced IADF frequency. Wet conditions during late summer/early autumn triggered the formation of IADFs in the three species. Our results suggest the existence of a common climatic driver for the formation of IADFs in Mediterranean pines, highlighting the potential use of IADF frequency as a proxy for climate reconstructions with geographical resolution.

  3. Seasonal distribution of processes responsible for radial diameter and wall thickness of Scots pine tracheids

    Directory of Open Access Journals (Sweden)

    G. F. Antonova

    2015-04-01

    Full Text Available The timeframes of processes responsible for the number of cells, their radial diameters and wall thickness in annual wood increment of Scots pine in the course of season vegetation were studied. The number of cells produced by cambium, cell radial diameters in the cell growth expansion zone and the thickness/wall tracheid cross-sectional area in the secondary wall thickening zone were estimated at the transverse sections of samples taken from the stems in 10 days. The data obtained were used for the calculation of the development durations of tracheids in the zones of differentiation and the dependence of these characteristics of the processes on air temperature. Throughout the season, the processes of the production by cambium of early and late tracheids, their radial growth and secondary wall thickening occurs at different times and may overlap each with another in time. In the conditions of Middle Siberia (Russia, the production of cambium cells was observed in June and July. Radial diameter growth of earlywood tracheids occurred mainly in June, latewood tracheids – in July. The development of secondary wall thickening of earlywood cells occurred in June-July, latewood ones – in August to the first half of September. Hydrothermal conditions of these months affect considerably the morphological parameters of the tracheids. Each of the processes reacted to environmental factors independently and had their own optimum temperatures causing the differences in cell wall biomass deposited in separate periods of the season. The data should be considered in addressing the problem of productivity and quality of wood produced in different climate conditions.

  4. 人工兴安落叶松次生木质部的解剖学研究%Anatomical studies about the secondary xylem of artificial Larix gmeini

    Institute of Scientific and Technical Information of China (English)

    赵西平; 秦丽丽; 杨利梅; 王大帅; 郑权; 张磊

    2014-01-01

    With wood anatomy image analysis system and micrography , anatomical structure of secondary xylem was ob-served and measured in artificial Larix gmeini.The results showed that Larix gmeini contained normal and injured resin ca-nal.The normal resin canal was commonly in latewood .From the earlywood to the latewood , the change was sharp in stem or branch, but was mild in the root .The shape of earlywood tracheid was hexagon or polygon .The single bordered pit was common in cell wall of earlywood tracheid , while the double bordered pit was unusual in them .The shape of Latewood tra-cheid was rectangular .The bordered pits were found seldom in the cell walls of latewood tracheid .It must be single bor-dered pit if the pits are found .There were single wood ray and spindle wood ray in Larix gmeini.Spindle wood rays only contained one longitudinal resin canal .The pit field formed by longitudinal tracheids and xylem rays is spruce type .From the root to the stem and branch , the size of tracheid was progressive elaboration , the length of xylem decreased , and distri-bution of rays were by the close to the sparse .%运用木材解剖图像分析系统和显微照相的方法对人工兴安落叶松次生木质部的解剖结构进行研究,结果表明:落叶松具正常树脂道和受伤树脂道两种类型,前者常见于晚材。落叶松生长轮内的早晚材在干和枝内急变,在根内缓变。早材管胞呈六边形至多边形,胞壁常见单列具缘纹孔,偶见对列具缘纹孔;晚材管胞多呈矩形,胞壁鲜见具缘纹孔,通常为单列具缘纹孔。落叶松木射线同时具有单列木射线和纺锤形木射线两种类型,纺锤形木射线中仅含一枚纵行树脂道。纵行管胞与木射线交叉形成的纹孔场为云杉型。从根到干再到枝,管胞逐渐细化,管胞长度逐渐减小,木射线分布由密到疏。

  5. Effects of physical blockage of axial phloem transport on growth of Norway spruce (Picea abies) saplings under drought

    Science.gov (United States)

    Oberhuber, Walter; Gruber, Andreas; Winkler, Andrea; Lethaus, Gina; Wieser, Gerhard

    2016-04-01

    Early culmination of maximum radial growth in late spring was found in several coniferous species in a dry inner Alpine environment (Oberhuber et al. 2014). We hypothesized that early decrease in radial stem growth is an adaptation to cope with drought stress, which might require an early switch of carbon allocation to belowground organs. To test this hypothesis we manipulated tree carbon status by physical blockage of phloem transport and soil water availability of Norway spruce saplings (tree height c. 1.5 m) in a common garden experiment to investigate influence of carbon availability and drought on above- and belowground growth. Girdling occurred at different phenological stages during the growing season, i.e., before growth onset, and during earlywood and latewood formation. Non-structural carbohydrates (NSC, soluble sugars and starch) were determined before and after the growing season to evaluate change in tree carbon status. Tree ring analysis revealed that compared to non-girdled controls earlywood width above girdling strikingly increased by c. 170 and 440 %, while latewood width decreased by c. 85 and 55 % in watered and drought stressed trees, respectively. Below girdling no xylem formation was detected. Unexpectedly, preliminary analyses of carbon status revealed striking reduction (c. -80 %) of NSC above and below girdling. Most likely due to reductions in xylem hydraulic conductance, girdling before growth onset reduced leader shoot growth compared to non-girdled controls by c. 45 %, irrespective of water availability. Root dry mass of girdled trees was significantly reduced compared to non-girdled controls (c. 30 % in drought stressed and 45 % in watered trees; p < 0.001). Results suggest that in Norway spruce saplings (1) carbon availability affects radial stem growth, (2) higher basipetal carbon transport occurs under drought supporting our hypothesis of early switch of carbon allocation to belowground when drought stress prevails and (3) minor

  6. Study on the longitudinal tensile strength of the tracheids of soft wood%针叶材管胞纵向抗拉强度研究

    Institute of Scientific and Technical Information of China (English)

    赵荣军; 程献宝; 孙娟; 王小青; 费本华

    2011-01-01

    以杉木、马尾松木材为试验材料,采用零距拉伸技术评价了木材管胞纵向抗拉强度,比较了不同含水率条件下管胞抗拉强度的差异,探讨了水分的影响机制.此外,重点研究了热处理对木材管胞纵向杭拉强度的影响,分析了管胞强度变化与化学成分、纤维素结晶度之间的关系.结果表明,衫木早材管胞纵向杭拉强度平均值为499MPa,马尾松早材管胞平均值461 MPa;两种木材管胞在饱水态下的抗拉强度比气干态均较低;在160-220℃、1-3h热处理条件下马尾松木材早材管胞纵向抗拉强度与素材相比有所降低.%In this paper, the longitudinal tensile strength of tracheids of Cunning hamia tanceolata and Pinus massoniana were evaluated using zero-span tensile test. The tensile strengths of wood tracheids with different moisture contents were compared, and the impact of the moisture on the tracheids' strength was discussed. In addition, the longitudinal tensile strengths of the tracheids of heat-treated wood were determined, which were correlated with changes in the chemical composition, and cellulose crystallmity induced by heat treatment. The results showed that the average tracheid's longitudinal tensile strength of Chinese fir and Masson pine earlywood were 499 M Pa and 461 Mpa, respectively. The longitudinal tensile strengths of Chinese fir and Masson pine under the condition of water-saturated state were lower than those under the air-dry state, and the longitudinal tensile strength of Masson pine earlywood tracheids treated under the condition of 160~220℃ for 1~3 h were lower than that of non-heat treatment.

  7. A Multi-Tree Perspective of Oxygen Isotope Variability in Longleaf Pine (Pinus palustris Mill.) Trees From Big Thicket National Preserve, Texas

    Science.gov (United States)

    Lewis, D. B.; Finkelstein, D. B.; Grissino-Mayer, H. D.; Mora, C. I.; Perfect, E.

    2008-12-01

    When trees utilize water from the upper portion of the soil column instead of deeper groundwater sources, a portion of the cellulose δ18O reflects the δ18O of soil water, which in turn is related to precipitation. Tropical cyclones can produce precipitation depleted in 18O by as much as 10--20‰ relative to normal precipitation. Therefore, oxygen isotope ratios of tree-ring cellulose can record information about past climate variability. However, factors such as soil moisture heterogeneity, canopy position, location within the stand or exposure may result in inconsistencies in the cellulose δ18O of individual trees in the same stand. These complexities may lead to difficulty utilizing single-tree oxygen isotope chronologies to characterize tropical cyclone events or regional climate variability. This study examined the seasonal (earlywood and latewood) δ18O of four individual trees growing in the same stand from 1982--2006 to determine the degree to which individual trees correlate to one another. Each tree was growing in the upper canopy, was similar in age, and occupied a location within the stand. Between-tree latewood δ18O correlations ranged between 0.41 and 0.58. All but one latewood series exhibited an overall negative trend over the 25-year period. Initial earlywood δ18O ratios display a similar negative trend. Time series correlations between individual latewood δ18O chronologies and monthly precipitation totals revealed no significant relationships of this data to fall precipitation. When the four latewood δ18O chronologies were averaged together, a significant seasonal (July--October) correlation was found (r= --0.55, p< 0.01). An autoregressive model (AR-1) was applied to each individual latewood isotope series to pinpoint years where cellulose δ18O indicated a depletion event. The resulting models were compared with local precipitation records to determine their accuracy in recording rains from tropical cyclone events. Although individual

  8. Studies on Variation of Poplar I-69 Tree-ring Width and Tree-ring Density%I-69杨年轮宽度和密度变异规律

    Institute of Scientific and Technical Information of China (English)

    王家祥; 夏萍; 刘盛全

    2011-01-01

    Poplar I-69 wood was chosen as the sample, the data of the components of tree-ring width and density were accessed by Tree-Ring Image Analysis System and Tree-Ring Analysis System and the radial and axial varia-tions of the components were analyzed. The results showed that; the radial variation of the density of poplar I-69 in-creased along with the tree age. The maximum density fluctuated heavy, the minimum density decreased along with increase of the tree age on the whole. The density of earlywood and latewood increased along with the tree age. The radial variation of the tree-ring components was significant within individual trunk, but no difference among trunks. The components of the tree-ring density increased along with the tree height, there into, the tree-ring average densi-ty , earlywood density and minimum density increased less, while the tree-ring maximum density and latewood densi-ty increased more. Comparatively, the radial variation of the density of poplar 1-69 was larger than that of the axial variation.%以I-69杨木材为试样,运用树木年轮图像分析系统和树木年轮分析系统获取年轮宽度和年轮密度数据,并对组成成分径向变异和轴向变异规律进行了分析.结果表明:I-69杨木材密度的径向变异规律随树龄增加而增大,最大密度波动较大,最小密度随树龄增加总体趋势下降,早材密度、晚材密度随树龄增加而增加;年轮组成成分各项指标株内径向变异极显著,株间径向变异不显著.年轮密度各组成成分随高度增加而增加,其中年轮平均密度、早材密度、最小密度增加量较小,年轮最大密度、晚材密度增加量较大;相对而言,I-69杨木材密度径向变异大于轴向变异.

  9. Flash-flood impacts cause changes in wood anatomy of Alnus glutinosa, Fraxinus angustifolia and Quercus pyrenaica.

    Science.gov (United States)

    Ballesteros, J A; Stoffel, M; Bollschweiler, M; Bodoque, J M; Díez-Herrero, A

    2010-06-01

    Flash floods may influence the development of trees growing on channel bars and floodplains. In this study, we analyze and quantify anatomical reactions to wounding in diffuse-porous (Alnus glutinosa L.) and ring-porous (Fraxinus angustifolia Vahl. and Quercus pyrenaica Willd.) trees in a Mediterranean environment. A total of 54 cross-sections and wedges were collected from trees that had been injured by past flash floods. From each of the samples, micro-sections were prepared at a tangential distance of 1.5 cm from the injury to determine wounding-related changes in radial width, tangential width and lumen of earlywood vessels, and fibers and parenchyma cells (FPC). In diffuse-porous A. glutinosa, the lumen area of vessels shows a significant (non-parametric test, P-value <0.05) decrease by almost 39% after wounding. For ring-porous F. angustifolia and Q. pyrenaica, significant decreases in vessel lumen area are observed as well by 59 and 42%, respectively. Radial width of vessels was generally more sensitive to the decrease than tangential width, but statistically significant values were only observed in F. angustifolia. Changes in the dimensions of earlywood FPC largely differed between species. While in ring-porous F. angustifolia and Q. pyrenaica the lumen of FPC dropped by 22 and 34% after wounding, we observed an increase in FPC lumen area in diffuse-porous A. glutinosa of approximately 35%. Our data clearly show that A. glutinosa represents a valuable species for flash-flood research in vulnerable Mediterranean environments. For this species, it will be possible in the future to gather information on past flash floods with non-destructive sampling based on increment cores. In ring-porous F. angustifolia and Q. pyrenaica, flash floods leave less drastic, yet still recognizable, signatures of flash-flood activity through significant changes in vessel lumen area. In contrast, the use of changes in FPC dimensions appears less feasible for the determination of

  10. Response of wood density of Picea crassifolia to climate change in Qilian Mountains of northwestern China%祁连山青海云杉木材密度对气候变化的响应

    Institute of Scientific and Technical Information of China (English)

    徐金梅; 吕建雄; 鲍甫成; 黄荣凤; 刘贤德; Robert Evans; 赵有科

    2011-01-01

    To investigate the response of wood density to climate change,wood density of Picea crassifolia trees at lower tree line in the middle Qilian Mountains,northwestern China was measured using Silviscan-3.Chronologies of annual,earlywood,latewood,maximum and minimum density were established by dendrochronological methods.Relationships of chronologies to monthly mean,maximum,minimum temperatures and monthly precipitation were analyzed.The results indicated that wood density of P.crassifolia trees positively correlated with temperatures and negatively correlated with precipitation.Annual and earlywood density significantly correlated with monthly mean temperatures in June to September,with monthly maximum temperatures in June,July and September,and with monthly minimum temperatures in October in previous year and in July and September in current year.Minimum density significantly correlated with temperature in June to August,with monthly maximum temperatures in June and July,and with monthly minimum temperatures in July.Annul density significantly correlated with precipitation in March.Earlywood and minimum density significantly correlated with precipitation in June.Latewood and maximum density did not show significant relationships with temperature and precipitation,latewood density was less sensitive to climate than earlywood density.Those results indicate that temperature has directly influence and precipitation has indirectly impact on wood density,temperature in summer is main climate factor influencing wood density of P.crassifolia in Qilian Mountains,northwestern China.%为探明木材密度对气候变化的响应,以祁连山中部下限青海云杉为研究对象,利用Silviscan-3测定了青海云杉的木材密度,根据树木年轮气候学的标准方法建立了年轮密度、早材密度、晚材密度、最大密度、最小密度年表,分析了各个木材密度年表与月平均温度、最高温度、最低温度和月降雨量的关系。结果发

  11. Characteristics of radial growth and stable isotopes in a single oak tree to be used in climate studies

    Energy Technology Data Exchange (ETDEWEB)

    Weigl, Martin [Competence Center for Wood Composites and Wood Chemistry, Competence Center Wood GmbH, St.-Peter-Str. 25, A-4021 Linz (Austria); University of Natural Resources and Applied Life Sciences, Vienna, Department of Material Sciences and Process Engineering, Peter Jordan Str. 82, A-1190 Vienna (Austria)], E-mail: m.weigl@kplus-wood.at; Grabner, Michael [University of Natural Resources and Applied Life Sciences, Vienna, Department of Material Sciences and Process Engineering, Peter Jordan Str. 82, A-1190 Vienna (Austria); Helle, Gerhard; Schleser, Gerhard H. [Institute for Chemistry and Dynamics of the Geosphere, ICG-V: Sedimentary Systems, Research Centre Juelich (FZJ), Leo-Brandt-Strasse D-52425 Juelich (Germany); Wimmer, Rupert [University of Natural Resources and Applied Life Sciences, Vienna, Department of Material Sciences and Process Engineering, Peter Jordan Str. 82, A-1190 Vienna (Austria)

    2008-04-01

    In this study we have analyzed the variability of tree-ring widths and stable isotopes ({delta}{sup 13}C and {delta}{sup 18}O) of a single sessile oak tree (Quercus petraea (Matt.) Liebl.) since these parameters are critical in reconstructing the environment, particularly climatic conditions. Tree rings were separated into early- and latewood (EW{sub t}; LW{sub t}), tree ring (TR{sub t}), and transfer tree ring (TTR{sub t}, the latter being the latewood plus the earlywood of the subsequent year. Mean sensitivity, simple correlation, partial correlation and autocorrelation analyses were applied to describe data and relationships. Although this research focused on a single tree, the results compared well with average site data. Widths and {delta}{sup 18}O values showed generally low autocorrelation for all tree-ring components, whereas {delta}{sup 13}C revealed highly significant autocorrelations for most tree-ring components. Mean sensitivity of the standardized values turned out to be high for {delta}{sup 18}O, marginally lower for width and the lowest for {delta}{sup 13}C. Correlation analyses have proven that the relationships within the tree-ring widths or within the isotope parameters are much stronger than across widths and isotope parameters. The study demonstrates the unique potential of all measured tree-ring data to be used as climate proxies.

  12. Characterization of Cypress Wood for Kraft Pulp Production

    Directory of Open Access Journals (Sweden)

    António J. A. Santos

    2014-06-01

    Full Text Available Wood samples of Cupressus arizonica, C. lusitanica, and C. sempervirens were evaluated for chemical, anatomical, and pulp characteristics as raw material for pulp production. Two 17-year-old trees per species were harvested, and wood samples were taken at a height of 2 m. Wood chips from Pinus pinaster (Portugal and P. sylvestris (Finland were used as references. C. arizonica differed from C. lusitanica and C. sempervirens with significantly lower (p < 0.05 tracheid diameter and wall thickness in the earlywood. The total extractives contents were 3.9%, 3.3%, and 2.5% for C. lusitanica, C. sempervirens, and C. arizonica, respectively, lower than the 5.1% for P. pinaster and 4.5% for P. sylvestris. Klason lignin content ranged from 33.0 to 35.6%, higher than the 28.0 to 28.7% for the pinewoods. The kraft pulp yields for C. arizonica, C. lusitanica, and C. sempervirens were 37.7%, 36.7%, and 38.7%, respectively, with kappa numbers of 32.0, 31.6, and 28.7, respectively; the yield values were 40.8% and 42.8%, with kappa numbers of 23.4 and 21.0, for P. pinaster and P. sylvestris, respectively. The cypress species are clearly different from pine in relation to wood pulping behavior. Among the cypress, C. sempervirens provided the best pulping results.

  13. Xylem dysfunction in Quercus: vessel sizes, tyloses, cavitation and seasonal changes in embolism.

    Science.gov (United States)

    Cochard, H; Tyree, M T

    1990-12-01

    The seasonal progression of xylem dysfunction from tyloses and embolism induced both by cavitation and frost was studied in Quercus rubra L. and Quercus alba L. branches. Vessel lengths and diameters were measured in current-year rings of branches of various ages. Vessels in current-year shoots are about the same size as those in many diffuse porous trees, but vessels in older branches are two to six times larger in diameter and typically more than 10 times longer. Large Quercus vessels were more vulnerable to cavitation than small vessels. The small vessels in current-year shoots were more vulnerable to cavitation than vessels of comparable size in diffuse porous species. Earlywood vessels are completely blocked by tyloses within a year of their formation. Tylose growth starts in winter, but the vessels are not fully blocked until the next summer. Many latewood vessels, by contrast, remain free of complete blockage for several years. In Q. rubra, loss of hydraulic conductivity in current-year shoots due to cavitation reaches 20% by August and > 90% after the first hard frost. Both laboratory and field observations confirm that the role of frost in causing loss of hydraulic conduction by embolism is much more dramatic in Quercus than in conifers and diffuse porous hardwoods.

  14. WOOD ANATOMICAL STUDY AMONG THREE ECOTYPES OF Pinus merkusii IN SUMATRA AND THE POTENTIAL AS CLIMATE CHANGE INDICATOR

    Directory of Open Access Journals (Sweden)

    Yulia Sandri

    2016-09-01

    Full Text Available Recently, climate change is the one of most important environmental issue. Climate variability can be recorded by tree growing through the growth ring. Growth ring formed by cambial activity were examined in wood anatomy. In Sumatra, there are three ecotypes Pinus merkusii, namely ecotypes Kerinci, Tapanuli, and Aceh which can be distinguished morphologically. This study aims to knowing the wood anatomical characteristics of the three ecotypes and determine the potential as climate indicator. This study was conducted in October 2014 until June 2015. Sample of Kerinci ecotype was collected in Kerinci Seblat National Park, Tapanuli ecotype in Dolok Sibualbuali Natural Reserve and Aceh ecotype in Gunung Leuser National Park on a height of 130 cm using increment borer and cut on the main stem 5×5 cm for anatomical sample. Results from this study indicate that ecotype Kerinci and Tapanuli showed earlywood and latewood boundary exposing the clear growth ring, whereas in Aceh ecotype unclear. Tapanuli ecotype have the thickest tracheid diameter than ecotype Kerinci and Aceh. Ecotypes of Kerinci, Tapanuli, and Aceh has homoceluler and uniseriate ray where Aceh ecotype have the longest ray. Furthermore, Kerinci and Tapanuli ecotype have potential as climate indicator eventhough showed negative correlation, that Tapanuli ecotype show the best result and recommended in dendrochronology study.

  15. Mechanical Properties of Wood from Transgenic Poplar Trees with Modified Lignification

    Institute of Scientific and Technical Information of China (English)

    X.Huang; G.Jeronimidis; J.F.V.Vincent

    2000-01-01

    Double cantilever beam (DCB) and instrumented microtome cutting (IMC) tests were carried out in testing wood fracture properties of control and various transgenic poplar plants. The results show that control plants have higher work of fracture (WF) than most transgenic plants. The air-dry materials have higher WF than wet ones and latewood is higher than earlywood. Also, samples from parts of the trunk above stye points usually have higher WF than those from below. The comparison between DCB tests and IMC studies show that, the WF obtained from DCB is higher than the cutting work measured by IMC. Scanning electronic microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to study specimens'fracture surfaces and structure. Though in all samples fracture occurred between the middle lamella and S1layers, between S1 and S2 layers, as well as within S2 layers, there are more transwall fractures in control plants.There are also differences in cell wall area fraction among these materials.

  16. Effect of compression combined with steam treatment on the porosity, chemical compositon and cellulose crystalline structure of wood cell walls.

    Science.gov (United States)

    Yin, Jiangping; Yuan, Tongqi; Lu, Yun; Song, Kunlin; Li, Hanyin; Zhao, Guangjie; Yin, Yafang

    2017-01-02

    The changes of porosity, chemical composition and cellulose crystalline structure of Spruce (Picea abies Karst.) wood cell walls due to compression combined with steam treatment (CS-treatment) were investigated by nitrogen adsorption, confocal Raman microscopy (CRM) and X-ray diffraction (XRD), respectively. A number of slit-shaped mesopores with a diameter of 3.7nm was formed for the CS-treated wood, and more mesopores were found in the steam-treated wood. CRM results revealed cellulose structure was affected by treatment and β-aryl-ether links associated to guaiacyl units of lignin was depolymerized followed by re-condensation reactions. The crystallinity index (CrI) and crystallite thickness (D200) of cellulose for CS-treated wood were largely increased due to crystallization in the semicrystalline region. Higher degree of increase in both CrI and D200 was observed in both the earlywood and latewood of steam-treated wood, ascribing to the greater amount of mesopores in steam-treated wood than CS-treated wood.

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

    Science.gov (United States)

    Souza, Brunna T; Estrada, Gustavo C D; Soares, Mário L G; Callado, Cátia H

    2016-01-01

    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.

  18. Changes of wood cell walls in response to hygro-mechanical steam treatment.

    Science.gov (United States)

    Guo, Juan; Song, Kunlin; Salmén, Lennart; Yin, Yafang

    2015-01-22

    The effects of compression combined with steam treatment (CS-treatment), i.e. a hygro-mechanical steam treatment on Spruce wood were studied on a cell-structure level to understand the chemical and physical changes of the secondary cell wall occurring under such conditions. Specially, imaging FT-IR microscopy, nanoindentation and dynamic vapour absorption were used to track changes in the chemical structure, in micromechanical and hygroscopic properties. It was shown that CS-treatment resulted in different changes in morphological, chemical and physical properties of the cell wall, in comparison with those under pure steam treatment. After CS-treatment, the cellular structure displayed significant deformations, and the biopolymer components, e.g. hemicellulose and lignin, were degraded, resulting in decreased hygroscopicity and increased mechanical properties of the wood compared to both untreated and steam treated wood. Moreover, CS-treatment resulted in a higher degree of degradation especially in earlywood compared to a more uniform behaviour of wood treated only by steam.

  19. Effect of steam treatment on the properties of wood cell walls.

    Science.gov (United States)

    Yin, Yafang; Berglund, Lars; Salmén, Lennart

    2011-01-10

    Steam treatment is a hygrothermal method of potential industrial significance for improving the dimensional stability and durability of wood materials. The steaming results in different chemical and micromechanical changes in the nanostructured biocomposite that comprise a wood cell wall. In this study, spruce wood ( Picea abies Karst.) that had been subjected to high-temperature steaming up to 180 °C was examined, using imaging Fourier Transform Infrared (FT-IR) microscopy and nanoindentation to track changes in the chemical structure and the micromechanical properties of the secondary cell wall. Similar changes in the chemical components, due to the steam treatment, were found in earlywood and latewood. A progressive degradation of the carbonyl groups in the glucuronic acid unit of xylan and a loss of mannose units in the glucomannan backbone, that is, a degradation of glucomannan, together with a loss of the C═O group linked to the aromatic skeleton in lignin, was found. The development of the hygroscopic and micromechanical properties that occurred with an elevation in the steam temperature correlated well with this pattern of degradation in the constituents in the biocomposite matrix in the cell wall (hemicellulose and lignin).

  20. [Cedrela odorata (Meliaceae) potential for dendrochronological studies in the Selva Central of Perú].

    Science.gov (United States)

    Pereyra Espinoza, Manuel Jesús; Inga Guillen, Gaby Janet; Santos Morales, Mariano; Arisméndiz Rodríguez, Rodolfo

    2014-06-01

    Despite the progress made during the past 20 years, searching dendrochronological potential in tropical and subtropical tree species, tropical dendrochronology, is still in a development stage. The aim of this research was to determine the potential of C. odorata for dendrochronological studies in the Selva Central of Perú. The tree-ring anatomical characteristics were carefully examined and we were able to develop a 215 year (1795-2 009) tree-ring chronology and correlate it with precipitation records. The tree-ring chronology was developed based on 47 series of 27 trees. Tree rings are clearly delimited by large pore diameters in earlywood and small ones in latewood associated with marginal and paratracheal parenchyma. The tree-ring chronology was related to precipitation records from Satipo and significant correlations were found with the previous rainy season and late dry season of the current growth period. Moreover, we found close relationship between tree growth and total precipitations of the hydrological period (December to September) for the interval 1990-2009. These results demonstrate the influence of rainfall at different stages of C. odorata radial growth. The good discrimination of annual rings, strong relationship with precipitation, the wide range and longevity of trees (200 years) make C. odorata a very promising species for dendrochronological studies in tropical and subtropical forest of America.

  1. May-July Temperature Variability Since 1801 Inferred from Tree Rings of Pinus tabulaeformis of Helan Mountains in China%树轮记录的贺兰山北部近208年5-7月温度变化

    Institute of Scientific and Technical Information of China (English)

    陈峰; 袁玉江; 魏文寿; 张同文; 张瑞波; 喻树龙; 范子昂; 李杨; 尚华明

    2011-01-01

    利用2008年10月采自贺兰山北部的油松树轮样本建立了贺兰山北部区域树轮密度年表.相关分析表明:贺兰山北部的树轮早材平均密度与银川气象站5-7月平均最高温度具有较好的正相关关系,相关系数为0.67.用贺兰山北部的区域早材平均密度差值年表重建贺兰山北部1801-2008年的5-7月平均最高温度,58年(1951-2008年)重建值对实测值的解释方差为44.9% 2008年的贺兰山北部温度重建序列平均值为27.40℃.在最近20年,贺兰山树轮早材平均密度出现了明显的上升趋势,通过比对贺兰山北部重建序列的低温年份和全球火山爆发数据,发现在大规模火山爆发后的28个偏冷年温度平均值为26.90℃,较重建序列平均值下降0.50℃.多窗谱分析表明:贺兰山北部温度重建序列具有120年、8.1年、6.5年、3.2年、2.9年、2.1年的准周期变化.贺兰山北部早材平均密度与甘肃石门山、昌灵山油松的早材平均密度有良好的相关性.%Ninety newly measured tree-ring width and density series from Chinese Pines (Pinus tabulaeformis) from four sites in Helan Mountains are compiled. To remove non-climatic, age-related growth trends from the raw tree-ring width and density measurement series, while allowing lower frequency information above the mean segment length to be preserved, the program ARSTAN is used to detrend the ring width and density sequences using hugershoff growth curve and to average the standardized ring width and density sequences into the master chronologies. The correlating coefficient between earlywood density record and May-July maximum temperature of Yinchuan reaches up to 0. 67 during 1951-2008. The May-July maximum temperature reconstruction (1801-2008) uses the earlywood density chronologies from the region. The explained variance of model is 44. 9% (F=45. 625, P<0. 0001). The mean temperature over the 1801-2008 periods is estimated to be 27. 4 ℃. The

  2. DENSIFICATION OF WOOD VENEERS COMBINED WITH OIL-HEAT TREATMENT. PART III: CELL WALL MECHANICAL PROPERTIES DETERMINED BY NANOINDENTATION

    Directory of Open Access Journals (Sweden)

    Cecillia Bustos Avila,

    2012-02-01

    Full Text Available Compression under the effect of heat and steam, also called thermo-hygromechanical (THM densification, can increase wood density and therefore improve its strength, stiffness, and hardness. Oil-heat treatment (OHT is also known to reduce wood’s hygroscopicity and improve dimensional stability. A combination of both treatments can therefore produce wood with improved mechanical properties and dimensional stability. The objective of this project was to determine cell wall mechanical properties of THM-densified and OHT wood. Trembling aspen veneers were densified by a THM process and subsequently treated in canola oil at 200 and 220°C. Nanoindentations were performed in earlywood cell walls. The results show that cell wall longitudinal modulus of elasticity increased significantly from 13.5 GPa for the control to a maximum of 18.2 GPa for THM densified wood with or without OHT. Cell wall hardness increased from 0.27 GPa to a maximum of 0.43 GPa. Both THM densification and OHT significantly increased cell wall hardness. Therefore, the increase in mechanical properties of THM-densified and OHT wood can be due to an increase in wood density resulting from a reduction in porosity but also to an increase in the mechanical properties of the cell wall.

  3. Traumatic resin ducts in Larix decidua stems impacted by debris flows.

    Science.gov (United States)

    Bollschweiler, Michelle; Stoffel, Markus; Schneuwly, Dominique M; Bourqui, Karin

    2008-02-01

    Following mechanical injury, stems of many conifers produce tangential rows of traumatic resin ducts (TRDs), the distribution of which has been used to date geomorphic events. However, little is known about how far TRD formation extends tangentially and axially from the point of injury or what the time course of TRD appearance is. We analyzed 28 injuries in eight Larix decidua Mill. tree stems resulting from debris flows in October 2000 and November 2004. Injuries occurred outside the period of cambial activity, and TRD formation occurred in the first layers of the growth ring formed in the year following that of injury. The axial extent of TRD formation averaged 74 cm and was greater above the injury than below it. At the height of the wound center, TRDs extended horizontally to a mean of 18% of the stem circumference excluding that portion where the cambium had been destroyed. In subsequent growth rings, TRDs, if present, were confined mainly to the height of the center of injury. Both the vertical and horizontal extent of TRD formation was related to the injury size. Within growth rings, the position of TRD formation changed with increasing distance from the wound progressing from early earlywood to later portions of the growth ring.

  4. Development of successive cambia, cambial activity, and their relationship to physiological traits in Ipomoea arborescens (Convolvulaceae) seedlings.

    Science.gov (United States)

    Terrazas, Teresa; Aguilar-Rodríguez, Silvia; Ojanguren, Clara Tinoco

    2011-05-01

    The seedling stage is one of the most critical phases in the life history of plants; during this stage, plants must develop efficient conductive and storage systems before the end of the favorable season. Little is known about the origin of successive cambia in seedlings of tree species of Ipomoea or about how many cambia are produced in one growth season. We studied the anatomy of Ipomoea arborescens seedlings to defi ne when cambium is differentiated, to determine how many cambia differentiate in one year of growth, and to relate the development of successive cambia to physiological aspects of growth. Seedlings from 5 to 425 d of age were harvested, and their morphology as well as CO(2) and water exchange, were evaluated at 5 and 60 d after germination. Six stages of development were established to study origin of cambia. Cambium was differentiated 5 d after germination, at a time when seedlings had photosynthetic cotyledons with high specific area, assimilation rate, and stomatal conductance. Differentiation of the fi rst successive cambium occurred inparenchyma cells below the endodermis or starch sheath. Development of reverse cambium and intraxylary phloem cambiumdemonstrated that ontogenetic shifts may occur in different stem regions. In the 10-mo-old plants, all cambia reactivated, and earlywood wide vessels were differentiated. The origin of successive cambia, the occurrence of more than one type of cambium, and parenchyma proliferation are features shared by I. arborescens with its climbing ancestors as a strategy for survival in the harsh environment of tropical deciduous forests.

  5. [Anatomic characterization of growth-rings in 80 potential tree species for dendrocronological studies in the Central Forest, Perú].

    Science.gov (United States)

    Beltrán Gutiérrez, Lizandro Adal; Valencia Ramos, Gina Mariela

    2013-09-01

    The knowledge about the existence of annual tree rings in tropical trees, which was already found at the beginning of the last century, was ignored by many scientists for a long time. Wood samples of 80 tree species from seven different sites belonging to Satipo and Chanchamayo provinces in Central Forest, Perú. Wood slices were taken at 1.30 m height, following the Peruvian Technical Norms (NTP) 251-008, COPANT norms 30:1-019 and IAWA (1989). Results showed that 24 of the 80 tree species analyzed showed a potential for dendrocronological studies, 25 had problems for growth-rings analysis, and 31 did not have potential. The problems most frequently found were: barely visible or irregular ring growth, parenchyma bands and multiseriate rays difficult to be identified in rings growth. The "T" Student test showed that the significant variation in vessel and fiber diameters between growth zones (Early-wood and late-wood) of species with potential for dendrocronology, do have a periodic cells production, so is possible to suggest the annual formation of each growth-ring. However, those species without potential to dendrocronology may be influenced by of a lot of factors, such as biotic and abiotic conditions of environment, as well as the genetic aspect of each species.

  6. Correlations between the anatomical traits of Gymnocladus canadensis Lam. in heartwood and sapwood of early- and latewood zones of growth rings

    Directory of Open Access Journals (Sweden)

    Jokanović Dušan

    2015-01-01

    Full Text Available This paper shows correlations between vessel characteristics and differences in growth-ring width in heartwood and sapwood. Analyzed samples were from an iron-wood tree (Gymnocladus canadensis Lam. that grew in the Mužljanski Rit area, of the Srpska Crnja municipality in Serbia. According to previous research, it was deduced that Gymnocladus canadensis Lam. belongs to ring-porous species with big vessel lumen in the earlywood zone and thicker cell walls in the latewood. Vessels were more numerous in the latewood zone, and the same was true for heartwood and sapwood. For both layers, sapwood possessed a few more vessels than heartwood, and a statistically significant difference was confirmed by t-test during the early phase. The greatest negative value of correlation coefficient was between the number of vessels and growth-ring width during the early phase for sapwood. The number of vessels decreased in the wider growth rings. The correlation between growth-ring width and the area of vessels had a statistically significant positive value of correlative coefficient, which means that wider growth rings had larger vessel areas in the early phase for sapwood. [Projekat Ministarstva nauke Republike Srbije, br. 31041

  7. New star on the stage: amount of ray parenchyma in tree rings shows a link to climate.

    Science.gov (United States)

    Olano, José Miguel; Arzac, Alberto; García-Cervigón, Ana I; von Arx, Georg; Rozas, Vicente

    2013-04-01

    Tree-ring anatomy reflects the year-by-year impact of environmental factors on tree growth. Up to now, research in this field has mainly focused on the hydraulic architecture, with ray parenchyma neglected despite the growing recognition of its relevance for xylem function. Our aim was to address this gap by exploring the potential of the annual patterns of xylem parenchyma as a climate proxy. We constructed ring-width and ray-parenchyma chronologies from 1965 to 2004 for 20 Juniperus thurifera trees growing in a Mediterranean continental climate. Chronologies were related to climate records by means of correlation, multiple regression and partial correlation analyses. Ray parenchyma responded to climatic conditions at critical stages during the xylogenetic process; namely, at the end of the previous year's xylogenesis (October) and at the onset of earlywood (May) and latewood formation (August). Ray parenchyma-based chronologies have potential to complement ring-width chronologies as a tool for climate reconstructions. Furthermore, medium- and low-frequency signals in the variation of ray parenchyma may improve our understanding of how trees respond to environmental fluctuations and to global change.

  8. 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.

  9. Rockfall and snow avalanche impacts leave different anatomical signatures in tree rings of juvenile Larix decidua.

    Science.gov (United States)

    Stoffel, Markus; Hitz, Oliver M

    2008-11-01

    Rockfall and snow avalanche events often cause injury to European larch (Larix decidua Mill.) trees, giving rise to the formation of callus tissue and tangential rows of traumatic resin ducts (TRDs). We analyzed and quantified anatomical reactions of juvenile trees injured before the start of the growing season by snow avalanches (15 trees, 324 cross sections) or rockfalls (18 trees, 270 cross sections). Traumatic resin ducts were observed in the growth ring formed following injury in 94.3% of the rockfall samples and 87.3% of the snow avalanche samples. Traumatic resin ducts were formed at the beginning of the new annual ring around wounds caused by rockfalls. In contrast, in trees injured by snow avalanches, TRDs were not formed until after the formation of several rows of early earlywood (EE) tracheids (mean +/- SD = 4.19 +/- 2.56 rows). The dimensions of the EE tracheids observed in the snow avalanche samples were greatly reduced in the tissues bordering the wound, with radial width reaching an average of only 50% and lumen cross-sectional area an average of only 46% of pre-event values. It is therefore possible to differentiate injuries due to past snow avalanches from injuries due to rockfall based on anatomical growth reactions in the tissues bordering scars.

  10. Generalized additive models reveal the intrinsic complexity of wood formation dynamics.

    Science.gov (United States)

    Cuny, Henri E; Rathgeber, Cyrille B K; Kiessé, Tristan Senga; Hartmann, Felix P; Barbeito, Ignacio; Fournier, Meriem

    2013-04-01

    The intra-annual dynamics of wood formation, which involves the passage of newly produced cells through three successive differentiation phases (division, enlargement, and wall thickening) to reach the final functional mature state, has traditionally been described in conifers as three delayed bell-shaped curves followed by an S-shaped curve. Here the classical view represented by the 'Gompertz function (GF) approach' was challenged using two novel approaches based on parametric generalized linear models (GLMs) and 'data-driven' generalized additive models (GAMs). These three approaches (GFs, GLMs, and GAMs) were used to describe seasonal changes in cell numbers in each of the xylem differentiation phases and to calculate the timing of cell development in three conifer species [Picea abies (L.), Pinus sylvestris L., and Abies alba Mill.]. GAMs outperformed GFs and GLMs in describing intra-annual wood formation dynamics, showing two left-skewed bell-shaped curves for division and enlargement, and a right-skewed bimodal curve for thickening. Cell residence times progressively decreased through the season for enlargement, whilst increasing late but rapidly for thickening. These patterns match changes in cell anatomical features within a tree ring, which allows the separation of earlywood and latewood into two distinct cell populations. A novel statistical approach is presented which renews our understanding of xylogenesis, a dynamic biological process in which the rate of cell production interplays with cell residence times in each developmental phase to create complex seasonal patterns.

  11. Wood anatomy and carbon-isotope discrimination support long-term hydraulic deterioration as a major cause of drought-induced dieback.

    Science.gov (United States)

    Pellizzari, Elena; Camarero, J Julio; Gazol, Antonio; Sangüesa-Barreda, Gabriel; Carrer, Marco

    2016-06-01

    Hydraulic impairment due to xylem embolism and carbon starvation are the two proposed mechanisms explaining drought-induced forest dieback and tree death. Here, we evaluate the relative role played by these two mechanisms in the long-term by quantifying wood-anatomical traits (tracheid size and area of parenchyma rays) and estimating the intrinsic water-use efficiency (iWUE) from carbon isotopic discrimination. We selected silver fir and Scots pine stands in NE Spain with ongoing dieback processes and compared trees showing contrasting vigour (declining vs nondeclining trees). In both species earlywood tracheids in declining trees showed smaller lumen area with thicker cell wall, inducing a lower theoretical hydraulic conductivity. Parenchyma ray area was similar between the two vigour classes. Wet spring and summer conditions promoted the formation of larger lumen areas, particularly in the case of nondeclining trees. Declining silver firs presented a lower iWUE than conspecific nondeclining trees, but the reverse pattern was observed in Scots pine. The described patterns in wood anatomical traits and iWUE are coherent with a long-lasting deterioration of the hydraulic system in declining trees prior to their dieback. Retrospective quantifications of lumen area permit to forecast dieback in declining trees 2-5 decades before growth decline started. Wood anatomical traits provide a robust tool to reconstruct the long-term capacity of trees to withstand drought-induced dieback.

  12. Application of micro-PIXE, MRI and light microscopy for research in wood science and dendroecology

    Science.gov (United States)

    Merela, M.; Pelicon, P.; Vavpetič, P.; Regvar, M.; Vogel-Mikuš, K.; Serša, I.; Poličnik, H.; Pokorny, B.; Levanič, T.; Oven, P.

    2009-06-01

    Beech ( Fagus sylvatica L.) branches were topped and after five months the wound response was analyzed by PIXE, 3D-MRI and light microscopy. From freshly cut and deeply frozen sample 30 μm thick longitudinal-radial tissue sections were prepared for anatomical investigations and micro-PIXE analysis. Light microscopy revealed the structural response to wounding, i.e. occurrence of the reaction zone between the exposed and dehydrated dead tissue and healthy sound wood. The reaction zone was characterized by tylosis in vessels and accumulation of colored deposits in parenchyma cells, fibres and vessels. 3D MRI of a parallel sample showed that the moisture content in the reaction zone was three times higher than in normal healthy wood. Micro-PIXE mapping at margins of compromised wood in beech revealed an increased concentration of potassium in the reaction zone. The increase in the calcium concentration was associated with the dehydrated tissue adjacent to reaction zones. In addition, micro-PIXE was used to determine the elemental distribution in annual tree rings. This may be relevant for retrospective assessment of environmental pollution in wood by measuring yearly increments as a biomonitoring tool. The analysis of European larch ( Larix decidua Mill.) wood revealed a high similarity between optical characteristics (i.e. late versus earlywood) and elemental (e.g. Cl, K, Ca, Mn, Zn) distribution.

  13. Changes in leaf organisation, photosynthetic performance and wood formation during ex vitro acclimatisation of black mulberry (Morus nigra L.).

    Science.gov (United States)

    Misalová, A; Durkovic, J; Mamonová, M; Priwitzer, T; Lengyelová, A; Hladká, D; Lux, A

    2009-09-01

    Changes in anatomical organisation of the leaf, photosynthetic performance and wood formation were examined to evaluate the temporal and spatial patterns of acclimatisation of micropropagated slow-growing black mulberry (Morus nigra L.) plantlets to the ex vitro environment. Leaf structure differentiation, the rates of net photosynthesis (P(n)), transpiration (E) and stomatal conductance (g(s)), and secondary xylem growth were determined in the course of a 56-day acclimatisation. Differentiation of palisade parenchyma was observed 7 days after transfer. At this stage, the rates of P(n), E and g(s) reached maximum values, after which the rates of all three gas exchange parameters gradually decreased. The highest proportion of woody area occupied by vessels was also observed 7 days after transfer. An important feature of developing woody tissue is the difference in patterns of vessel distribution from the characteristic differentiation patterns of earlywood and latewood vessels in mature wood of ring-porous trees. Vessels with lumen areas over 3000 microm(2) were only differentiated in acclimatised plantlets, whereas vessels in stems sampled on days 0 and 7 had very small lumen areas of up to 560 microm(2). Full acclimatisation, observed 56 days after transfer to the ex vitro environment, was associated with the rapid growth of new in vivo formed leaves, very low rates of E and g(s), and much increased secondary xylem tissue within the stem area.

  14. Application of micro-PIXE, MRI and light microscopy for research in wood science and dendroecology

    Energy Technology Data Exchange (ETDEWEB)

    Merela, M. [University of Ljubljana, BF, Dep. of Wood Science and Technology, Rozna dolina VIII/34, SI-1000 Ljubljana (Slovenia); Pelicon, P. [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)], E-mail: primoz.pelicon@ijs.si; Vavpetic, P. [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Regvar, M.; Vogel-Mikus, K. [University of Ljubljana, BF, Dep. of Biology, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Sersa, I. [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Policnik, H. [ERICo Velenje, Ecological Research and Industrial Co-operation, Koroska 58, SI-3320 Velenje (Slovenia); Pokorny, B. [ERICo Velenje, Ecological Research and Industrial Co-operation, Koroska 58, SI-3320 Velenje (Slovenia); Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana (Slovenia); Levanic, T. [Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana (Slovenia); Oven, P. [University of Ljubljana, BF, Dep. of Wood Science and Technology, Rozna dolina VIII/34, SI-1000 Ljubljana (Slovenia)

    2009-06-15

    Beech (Fagus sylvatica L.) branches were topped and after five months the wound response was analyzed by PIXE, 3D-MRI and light microscopy. From freshly cut and deeply frozen sample 30 {mu}m thick longitudinal-radial tissue sections were prepared for anatomical investigations and micro-PIXE analysis. Light microscopy revealed the structural response to wounding, i.e. occurrence of the reaction zone between the exposed and dehydrated dead tissue and healthy sound wood. The reaction zone was characterized by tylosis in vessels and accumulation of colored deposits in parenchyma cells, fibres and vessels. 3D MRI of a parallel sample showed that the moisture content in the reaction zone was three times higher than in normal healthy wood. Micro-PIXE mapping at margins of compromised wood in beech revealed an increased concentration of potassium in the reaction zone. The increase in the calcium concentration was associated with the dehydrated tissue adjacent to reaction zones. In addition, micro-PIXE was used to determine the elemental distribution in annual tree rings. This may be relevant for retrospective assessment of environmental pollution in wood by measuring yearly increments as a biomonitoring tool. The analysis of European larch (Larix decidua Mill.) wood revealed a high similarity between optical characteristics (i.e. late versus earlywood) and elemental (e.g. Cl, K, Ca, Mn, Zn) distribution.

  15. 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.

  16. Elemental analysis of wood materials by external millibeam thick target PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Saarela, K.-E.

    2009-07-01

    PIXE (Particle Induce X-ray Emission spectrometry) was used for analysing stem bark and stem wood of Scots pine, Norway spruce and Silver birch. Thick samples were irradiated, in laboratory atmosphere, with 3 MeV protons and the beam current was measured indirectly using a photo multiplicator (PM) tube. Both point scans and bulk analyses were performed with the 1 mm diameter proton beam. In bulk analyses, whole bark and sectors of discs of the stem wood were dry ashed at 550 deg C. The ashes were homogenised by shaking and prepared to target pellets for PIXE analyses. This procedure generated representative samples to be analysed, but the enrichment also enabled quantification of some additional trace elements. The ash contents obtained as a product of the sample preparation procedure also showed to be of great importance in the evaluation of results in environmental studies. Spot scans from the pith of pine wood outwards, showed clearly highest concentrations of manganese, calcium and zinc in the first spot irradiated, or 2-3 times higher than in the surrounding wood. For stem wood from the crown part of a pine this higher concentration level was found in the first four spots/mms, including the pith and the two following growth rings. Zinc showed increasing concentrations outwards in sapwood of the pine stem, with the over-all lowest concentrations in the inner half of the sapwood. This could indicate emigration of this element from sapwood being under transformation to heartwood. Point scans across sapwood of pine and spruce showed more distinct variations in concentrations relative to hearth wood. Higher concentrations of e.g. zinc, calcium and manganese were found in earlywood than in denser latewood. Very high concentrations of iron and copper were also seen for some earlywood increments. The ash content of stem bark is up to and order higher than for the stem wood. However, when the elemental concentration in ashes of bark and wood of the same disc were

  17. Powdery Mildew Decreases the Radial Growth of Oak Trees with Cumulative and Delayed Effects over Years

    Science.gov (United States)

    Bert, Didier; Lasnier, Jean-Baptiste; Capdevielle, Xavier; Dugravot, Aline; Desprez-Loustau, Marie-Laure

    2016-01-01

    Quercus robur and Q. petraea are major European forest tree species. They have been affected by powdery mildew caused by Erysiphe alphitoides for more than a century. This fungus is a biotrophic foliar pathogen that diverts photosynthetate from the plant for its own nutrition. We used a dendrochronological approach to investigate the effects of different levels of infection severity on the radial growth of young oak trees. Oak infection was monitored at individual tree level, at two sites in southwestern France, over a five-year period (2001–2005). Mean infection severity was almost 75% (infected leaf area) at the end of the 2001 growing season, at both sites, but only about 40% in 2002, and 8%, 5% and 2% in 2003, 2004 and 2005, respectively. Infection levels varied considerably between trees and were positively related between 2001 and 2002. Increment cores were taken from each tree to assess annual ring widths and increases in basal area. Annual radial growth was standardised to take the effect of tree size into account. Annual standardised radial growth was significantly and negatively correlated with infection severity in the same year, for both 2001 and 2002, and at both sites. The decrease in growth reached 70–90% for highly infected trees. The earlywood width was poorly correlated with infection severity, but the proportion of latewood in tree rings was lower in highly infected trees (60%) than in less heavily infected trees (85%). Infection in 2001 and 2002 was found to have a cumulative effect on radial growth in these years, together with a delayed effect detectable in 2003. Thus, even non-lethal pathogens like powdery mildew can have a significant impact on tree functioning. This impact should be taken into account in growth and yield models, to improve predictions of forest net primary production. PMID:27177029

  18. Assessment of tree response to drought: validation of a methodology to identify and test proxies for monitoring past environmental changes in trees.

    Science.gov (United States)

    Tene, A; Tobin, B; Dyckmans, J; Ray, D; Black, K; Nieuwenhuis, M

    2011-03-01

    A thinning experiment stand at Avoca, Ballinvalley, on the east coast of the Republic of Ireland was used to test a developed methodology aimed at monitoring drought stress, based on the analysis of growth rings obtained by coring. The stand incorporated six plots representing three thinning regimes (light, moderate and heavy) and was planted in the spring of 1943 on a brown earth soil. Radial growth (early- and latewood) was measured for the purpose of this study. A multidisciplinary approach was used to assess historic tree response to climate: specifically, the application of statistical tools such as principal component and canonical correlation analysis to dendrochronology, stable isotopes, ring density proxy, blue reflectance and forest biometrics. Results showed that radial growth was a good proxy for monitoring changes to moisture deficit, while maximum density and blue reflectance were appropriate for assessing changes in accumulated temperature for the growing season. Rainfall also influenced radial growth changes but not significantly, and was a major factor in stable carbon and oxygen discrimination, mostly in the latewood formation phase. Stable oxygen isotope analysis was more accurate than radial growth analysis in drought detection, as it helped detect drought signals in both early- and latewood while radial growth analysis only detected the drought signal in earlywood. Many studies have shown that tree rings provide vital information for marking past climatic events. This work provides a methodology to better identify and understand how commonly measured tree proxies relate to environmental parameters, and can best be used to characterize and pinpoint drought events (variously described using parameters such as like moisture deficit, accumulated temperature, rainfall and potential evaporation).

  19. Tree-ring latewood width based July-August SPEI reconstruction in South China since AD 1888 and its possible connection with ENSO

    Science.gov (United States)

    Zhao, Yesi; Shi, Jiangfeng; Shi, Shiyuan; Yu, Jian; Lu, Huayu

    2017-04-01

    Our understanding of the long-term hydroclimate variations in South China is prohibited by the shortness of meteorological records. Paleoclimatic proxies, such as tree-rings, can be pursued to extend the meteorological records back for centuries to help us better understand hydroclimatic conditions. In this study, we reconstructed the July-August Standardized Precipitation-Evapotranspiration Index (SPEIJul-Aug) based on a newly developed 127-year adjusted latewood width chronology from Tsuga longibracteata, South China. In specific, the latewood width chronology was regressed on the earlywood width chronology using a simple linear regression, and the residuals plus a constant 1.0 were defined as the adjusted latewood width chronology. The chronology explained 40% of the actual SPEIJul-Aug variance in the period 1953-2014. The reconstructed SPEIJul-Aug can represent large-scale July-August SPEI variations over South China, including northern Guangxi, Hunan, and Guizhou provinces. From the perspective of the past 127 years, the extreme summer drought in 2013 was not unusual because more extreme drought events occurred in the first half of the 20th century. A significant 2.0-3.6-year hydroclimatic cycle existed in the reconstruction, which indicated that the SPEIJul-Aug might be driven by El Niño-Southern Oscillation (ENSO). We further checked the time-dependency of the relationship between SPEIJul-Augand ENSO and found that it was unstable. Their relationship was weak before the 1950s, became significant from the 1950s to early 1990s, and then dropped to be weak again and even out of phase since the early 1990s, which may be attributable to the significant westward extension of the western Pacific subtropical high. This study indicates that summer hydroclimate in South China can be reconstructed based on adjusted latewood width, and will be better understood when more and longer adjusted latewood width chronologies are obtained in the near future.

  20. Seasonal, Inter-annual and Long Term Trends in the Element Composition of Tropical Tree Rings

    Science.gov (United States)

    Verheyden, A.; Beeckman, H.; Andre, L.

    2008-12-01

    The inorganic composition of Rhizophora mucronata wood was studied on 11 stem discs collected from two mangrove forests in Kenya. The aim of this preliminary study was to assess if elements could be used as proxies of environmental and/or anthropogenic change. Earlywood and late wood were separated and analyzed on ICP-MS and ICP-OES. A remarkable synchronicity was found between ring width and Mg/Ca and Mn/Ca ratios, both of which have been used as soil pH proxies. However, there was also a negative correlation between Ca and ring width, indicating a dilution effect at higher growth rates. The essential elements P and K were significantly higher in fast growing plantation trees, suggesting that these elements might be useful as nutrient proxies in mangrove wood. A high correlation was found between Ca and Sr in the wood, indicating that probably no differentiation is made by the tree during incorporation of these elements in the wood. Since Sr/Ca of seawater is related to salinity, we suggest that the Sr/Ca in the wood could be used as a salinity proxy for tree species growing in brackish waters. Finally, a high-resolution study was also conducted using LA-ICP-MS, which revealed a high spatial variability within one ring. This high variability was the result of different concentrations in each wood cell type analyzed. The heavy metals (Cu, Zn, Pb and Cr), as well as Ba, had highest concentrations in the fibers and lowest in the vessels. On the other hand, B, Mn, Ca, P, and Sr were highest in the rays and vessels and lowest in the fibers, while Mg was the highest in the rays, but lowest in the vessels. The implications of these results for the use of trace elements to delimit chemical ring boundaries in tropical trees will be discussed.

  1. Measuring medium-term sheet erosion in gullies from trees: A case study using dendrogeomorphological analysis of exposed pine roots in central Iberia

    Science.gov (United States)

    Bodoque, J. M.; Lucía, A.; Ballesteros, J. A.; Martín-Duque, J. F.; Rubiales, Juan M.; Genova, M.

    2011-11-01

    The assessment of gully erosion poses a great challenge because of the complexity and connectivity of the geomorphic processes involved. This study focuses on the quantification of sheet erosion rates in a set of slope gullies located on the northern piedmont of the Guadarrama Mountains (Spanish Central System). In order to delineate accurately the gully areas in which sheet erosion was predominant, the Hydrologic/Erosion Response Unit (HRU/ERU) approach was used and a dendrogeomorphological analysis of exposed tree roots was carried out to quantify sheet erosion rates in one selected HRU/ERU. Identification of the first year of exposure by erosion from anatomical criteria was therefore critical. The 29 samples taken were prepared for anatomical analysis and cross-dated. Anatomical analysis of the samples showed a reduction in the lumen area of earlywood tracheids following root exposure and also, in most cases, a slight increase in growth rings. Moreover, at the end of the ring, latewood tissue and visible annual borders were very clearly defined by several rows of thick-walled tracheids. A non-parametric test was used on the findings derived from this qualitative analysis to objectify determination of the first year of exposure. Estimates of sheet erosion were obtained by dividing the height of eroded soil by the number of years that each root was exposed. The mean value of soil erosion for the entire study site was then determined from statistical inference. Using this procedure, a range of sheet erosion rates between 6.2 and 8.8 mm y -1 (125.2 and 177.8 t ha -1 year -1) was obtained for the dominant HRU/ERU of these gullies in central Iberia. These estimates of eroded soil thickness were adjusted based on the recent finding that root anatomical changes occur prior to their exposure by erosion.

  2. Reconstruction of soil moisture for the past 100 years in eastern Siberia by using δ13C of larch tree rings

    Science.gov (United States)

    Tei, Shunsuke; Sugimoto, Atsuko; Yonenobu, Hitoshi; Yamazaki, Takeshi; Maximov, Trofim C.

    2013-07-01

    stable carbon isotope ratio (δ13C) chronology for the past 100 years was developed from larch tree rings in eastern Siberia (near Yakutsk, 62°14'N, 129°37'E), to reconstruct past soil moisture water equivalent (SWE). Based on the correlation analyses between SWE and tree ring δ13C, we developed a linear regression model for SWE in the late growing period (LGP: 15 July to 31 August) using annual tree ring δ13C, which was calculated from the combination of latewood in a current year and earlywood in the following year, and then reconstructed SWE (LGP) for 1908-2007. Reconstructed SWE was compared with factors such as the output of the land surface model, annual precipitation, and Palmer Drought Severity Index for July. From the results, the reconstructed SWE appears reasonable and shows a large variation, including repeated occurrences of severe drought and an unprecedented high soil moisture event in 2006-2007 during the past 100 years. The reconstruction also captured a past documented record of severe drought in the 1940s. Despite the generally good performance of the reconstruction, by the 1930s the estimated SWE was higher than that expected from the annual precipitation. Tree ring width and δ13C were negatively correlated in most periods. However, the negative correlation was weaker for the period from 1919 to 1925, when relatively low air temperature was observed. This result suggests that the rate of photosynthesis, together with the degree of stomata opening, also affected the tree ring δ13C during cool periods.

  3. The Dynamics and Variability of Radial Growth in Provenance Trials of Norway Spruce (Picea abies (L. Karst. Within and Beyond the Hot Margins of its Natural Range

    Directory of Open Access Journals (Sweden)

    Neculae ŞOFLETEA

    2015-04-01

    Full Text Available Multi-site field trials provide valuable data for the investigation of possible effects of environmental changes on forest tree species. We analyze the descendants of plus trees from 33 Norway spruce seed sources of Romanian Carpathians, at age 30, in four comparative field trials: two established in the natural range of species and two outside of it. The dynamics and variation of radial growth, earlywood and latewood were analyzed. The influence of populations, site conditions and climatic factors were also quantified. The provenances response in the four comparative trials was asymmetric for mean radial growth, but its dynamics was less favourable outside of the natural range. Analysis of variance showed significant differences (P<0.001 between the testing sites, but non-significant (P<0.05 for the populations. Populations x localities interaction was high (P<0.001 in the first half of the testing period, but decreased over time, becoming not significant at the age of 30. At intra-populational level, the average coefficient of variation for radial growth was higher outside the natural range, whereas the proportion of latewood decreased. The temperature in the first half of the growing season negatively influenced (P<0.001 the radial increment, but in the latewood proportion significat effects (P˂0.05 were recorded only in trials located outside of the natural range. An increased variability of radial growth and a decrease of latewood proportion are expected in Norway spruce stands located at lower altitudes, towards the limits of the natural range. Our results may contribute to the sustainable management of Norway spruce forests within and outside its natural range.

  4. Powdery Mildew Decreases the Radial Growth of Oak Trees with Cumulative and Delayed Effects over Years.

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    Didier Bert

    Full Text Available Quercus robur and Q. petraea are major European forest tree species. They have been affected by powdery mildew caused by Erysiphe alphitoides for more than a century. This fungus is a biotrophic foliar pathogen that diverts photosynthetate from the plant for its own nutrition. We used a dendrochronological approach to investigate the effects of different levels of infection severity on the radial growth of young oak trees. Oak infection was monitored at individual tree level, at two sites in southwestern France, over a five-year period (2001-2005. Mean infection severity was almost 75% (infected leaf area at the end of the 2001 growing season, at both sites, but only about 40% in 2002, and 8%, 5% and 2% in 2003, 2004 and 2005, respectively. Infection levels varied considerably between trees and were positively related between 2001 and 2002. Increment cores were taken from each tree to assess annual ring widths and increases in basal area. Annual radial growth was standardised to take the effect of tree size into account. Annual standardised radial growth was significantly and negatively correlated with infection severity in the same year, for both 2001 and 2002, and at both sites. The decrease in growth reached 70-90% for highly infected trees. The earlywood width was poorly correlated with infection severity, but the proportion of latewood in tree rings was lower in highly infected trees (60% than in less heavily infected trees (85%. Infection in 2001 and 2002 was found to have a cumulative effect on radial growth in these years, together with a delayed effect detectable in 2003. Thus, even non-lethal pathogens like powdery mildew can have a significant impact on tree functioning. This impact should be taken into account in growth and yield models, to improve predictions of forest net primary production.

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

    Science.gov (United States)

    Leavitt, Steven W

    2010-10-15

    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‰ for δ(13)C, 1-4‰ δ(18)O, and 5-30‰ 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.

  6. Size Matters a Lot: Drought-Affected Italian Oaks Are Smaller and Show Lower Growth Prior to Tree Death

    Science.gov (United States)

    Colangelo, Michele; Camarero, Jesús J.; Borghetti, Marco; Gazol, Antonio; Gentilesca, Tiziana; Ripullone, Francesco

    2017-01-01

    Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two Italian oak forests showing recent mortality episodes. The mortality probability of trees is modeled as a function of recent growth and tree size. Drift-diffusion-jump (DDJ) metrics are used to detect early-warning signals. We found that the tallest trees of the anisohydric Italian oak better survived drought contrary to what was predicted by the theory. Dead trees were characterized by a lower height and radial-growth trend than living trees in both study sites. The growth reduction of now-dead trees started about 10 years prior to their death and after two severe spring droughts during the early 2000s. This critical transition in growth was detected by DDJ metrics in the most affected site. Dead trees were also more sensitive to drought stress in this site indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. Since living and dead trees showed similar competition we did not expect that moderate thinning and a reduction in tree density would increase the short-term survival probability of trees. PMID:28270816

  7. Xylogenesis: Coniferous Trees of Temperate Forests Are Listening to the Climate Tale during the Growing Season But Only Remember the Last Words!

    Science.gov (United States)

    Cuny, Henri E; Rathgeber, Cyrille B K

    2016-05-01

    The complex inner mechanisms that create typical conifer tree-ring structure (i.e. the transition from large, thin-walled earlywood cells to narrow, thick-walled latewood cells) were recently unraveled. However, what physiological or environmental factors drive xylogenesis key processes remain unclear. Here, we aim to quantify the influence of seasonal variations in climatic factors on the spectacular changes in the kinetics of wood cell differentiation and in the resulting tree-ring structure. Wood formation was monitored in three sites over 3 years for three coniferous species (Norway spruce [Picea abies], Scots pine [Pinus sylvestris], and silver fir [Abies alba]). Cell differentiation rates and durations were calculated and related to tracheid final dimensions and corresponding climatic conditions. On the one hand, we found that the kinetics of cell enlargement and the final size of the tracheids were not explained by the seasonal changes in climatic factors. On the other hand, decreasing temperatures strongly constrained cell wall deposition rates during latewood formation. However, the influence of temperature was permanently written into tree-ring structure only for the very last latewood cells, when the collapse of the rate of wall deposition was no longer counterbalanced by the increase of its duration. Our results show that the formation of the typical conifer tree-ring structure, in normal climatic conditions, is only marginally driven by climate, suggesting strong developmental control of xylogenesis. The late breakage of the compensatory mechanism at work in the wall deposition process appears as a clue to understand the capacity of the maximum latewood density to record past temperature conditions. © 2016 American Society of Plant Biologists. All Rights Reserved.

  8. Xylogenesis: Coniferous Trees of Temperate Forests Are Listening to the Climate Tale during the Growing Season But Only Remember the Last Words!1

    Science.gov (United States)

    2016-01-01

    The complex inner mechanisms that create typical conifer tree-ring structure (i.e. the transition from large, thin-walled earlywood cells to narrow, thick-walled latewood cells) were recently unraveled. However, what physiological or environmental factors drive xylogenesis key processes remain unclear. Here, we aim to quantify the influence of seasonal variations in climatic factors on the spectacular changes in the kinetics of wood cell differentiation and in the resulting tree-ring structure. Wood formation was monitored in three sites over 3 years for three coniferous species (Norway spruce [Picea abies], Scots pine [Pinus sylvestris], and silver fir [Abies alba]). Cell differentiation rates and durations were calculated and related to tracheid final dimensions and corresponding climatic conditions. On the one hand, we found that the kinetics of cell enlargement and the final size of the tracheids were not explained by the seasonal changes in climatic factors. On the other hand, decreasing temperatures strongly constrained cell wall deposition rates during latewood formation. However, the influence of temperature was permanently written into tree-ring structure only for the very last latewood cells, when the collapse of the rate of wall deposition was no longer counterbalanced by the increase of its duration. Our results show that the formation of the typical conifer tree-ring structure, in normal climatic conditions, is only marginally driven by climate, suggesting strong developmental control of xylogenesis. The late breakage of the compensatory mechanism at work in the wall deposition process appears as a clue to understand the capacity of the maximum latewood density to record past temperature conditions. PMID:27208048

  9. Sub-annual variability in historical water source use by Mediterranean riparian trees.

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    Sargeant, Christopher; Singer, Michael

    2016-04-01

    The seasonal availability of water within a tree's rooting zone may be an important determinant for individual tree growth and overall forest health, particularly in riparian corridors of Mediterranean climate zones that are vulnerable to water stress. Here, we present a new method that combines dendro-isotopes and isotope-modelling for determining how water source use varies over 10 consecutive growing seasons (2000-2010) for co-occurring species P. nigra and F. excelsior, along the Rhône River, south-eastern France. We conducted highly resolved cellulose δ18O analysis of micro-slices within tree rings and back-calculated the δ18O signature of source water available at the time of growth using a biochemical fractionation model. We related these patterns to inferred seasonal hydrological partitioning through comparison with δ18O of waters from the vadose and phreatic zones, precipitation, and streamflow. The shallowly rooted Fraxinus displayed greater sub-annual source water variability, as well as greater isotopic enrichment, reflecting use of precipitation-derived vadose moisture. Its earlywood component was formed mainly from winter rainfall (depleted) whilst the latewood relied on growing season precipitation (enriched). In Populus, the sub-annual source water use was relatively depleted, suggesting use of hyporheic water and regional groundwater. From 2007, both species converged in their pattern of water source uptake which was attributed to a decline in phreatic water access for Populus. These results demonstrate that the seasonal variability in source water use can be identified retrospectively, a method which may prove important for anticipating the future consequences of climatic driven changes to the hydrological cycle.

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

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    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.

  11. Latitudinal gradients in tree ring stable carbon and oxygen isotopes reveal differential climate influences of the North American Monsoon System

    Science.gov (United States)

    Szejner, Paul; Wright, William E.; Babst, Flurin; Belmecheri, Soumaya; Trouet, Valerie; Leavitt, Steven W.; Ehleringer, James R.; Monson, Russell K.

    2016-07-01

    The arrival of the North American Monsoon System (NAMS) terminates a presummer hyperarid period in the southwestern United States (U.S.), providing summer moisture that is favorable for forest growth. Montane forests in this region rely on winter snowpack to drive much of their growth; the extent to which they use NAMS moisture is uncertain. We addressed this by studying stable carbon and oxygen isotopes in earlywood and latewood from 11 sites along a latitudinal gradient extending from Arizona and New Mexico to Utah. This study provides the first regional perspective on the relative roles of winter versus summer precipitation as an ecophysiological resource. Here we present evidence that Ponderosa pine uses NAMS moisture differentially across this gradient. 13C/12C ratios suggest that photosynthetic water use efficiency during latewood formation is more sensitive to summer precipitation at the northern than at the southern sites. This is likely due to the fact that NAMS moisture provides sufficiently favorable conditions for tree photosynthesis and growth during most years in the southern sites, whereas the northern sites experience larger summer moisture variability, which in some years is limiting growth. Cellulose δ18O and δ13C values revealed that photoassimilates in the southern sites were produced under higher vapor pressure deficit conditions during spring compared to summer, demonstrating a previously underappreciated effect of seasonal differences in atmospheric humidity on tree ring isotope ratios. Our findings suggest that future changes in NAMS will potentially alter productivity and photosynthetic water use dynamics differentially along latitudinal gradients in southwestern U.S. montane forests.

  12. Comparing the intra-annual wood formation of three European species (Fagus sylvatica, Quercus petraea and Pinus sylvestris) as related to leaf phenology and non-structural carbohydrate dynamics.

    Science.gov (United States)

    Michelot, Alice; Simard, Sonia; Rathgeber, Cyrille; Dufrêne, Eric; Damesin, Claire

    2012-08-01

    Monitoring cambial phenology and intra-annual growth dynamics is a useful approach for characterizing the tree growth response to climate change. However, there have been few reports concerning intra-annual wood formation in lowland temperate forests with high time resolution, especially for the comparison between deciduous and coniferous species. The main objective of this study was to determine how the timing, duration and rate of radial growth change between species as related to leaf phenology and the dynamics of non-structural carbohydrates (NSC) under the same climatic conditions. We studied two deciduous species, Fagus sylvatica L. and Quercus petraea (Matt.) Liebl., and an evergreen conifer, Pinus sylvestris L. During the 2009 growing season, we weekly monitored (i) the stem radial increment using dendrometers, (ii) the xylem growth using microcoring and (iii) the leaf phenology from direct observations of the tree crowns. The NSC content was also measured in the eight last rings of the stem cores in April, June and August 2009. The leaf phenology, NSC storage and intra-annual growth were clearly different between species, highlighting their contrasting carbon allocation. Beech growth began just after budburst, with a maximal growth rate when the leaves were mature and variations in the NSC content were low. Thus, beech radial growth seemed highly dependent on leaf photosynthesis. For oak, earlywood quickly developed before budburst, which probably led to the starch decrease quantified in the stem from April to June. For pine, growth began before the needles unfolding and the lack of NSC decrease during the growing season suggested that the substrates for radial growth were new assimilates of the needles from the previous year. Only for oak, the pattern determined from the intra-annual growth measured using microcoring differed from the pattern determined from dendrometer data. For all species, the ring width was significantly influenced by growth duration

  13. Impact of drought on the temporal dynamics of wood formation in Pinus sylvestris.

    Science.gov (United States)

    Gruber, Andreas; Strobl, Stefan; Veit, Barbara; Oberhuber, Walter

    2010-04-01

    We determined the temporal dynamics of cambial activity and xylem cell differentiation of Scots pine (Pinus sylvestris L.) within a dry inner Alpine valley (750 m a.s.l., Tyrol, Austria), where radial growth is strongly limited by drought in spring. Repeated micro-sampling of the developing tree ring of mature trees was carried out during two contrasting years at two study plots that differ in soil water availability (xeric and dry-mesic sites). In 2007, when air temperature at the beginning of the growing season in April exceeded the long-term mean by 6.4 degrees C, cambial cell division started in early April at both study plots. A delayed onset of cambial activity of c. 2 weeks was found in 2008, when average climate conditions prevailed in spring, indicating that resumption of cambial cell division after winter dormancy is temperature controlled. Cambial cell division consistently ended about the end of June/early July in both study years. Radial enlargement of tracheids started almost 3 weeks earlier in 2007 compared with 2008 at both study plots. At the xeric site, the maximum rate of tracheid production in 2007 and 2008 was reached in early and mid-May, respectively, and c. 2 weeks later at the dry-mesic site. Since in both study years more favorable growing conditions (i.e., an increase in soil water content) were recorded during summer, we suggest a strong sink competition for carbohydrates to mycorrhizal root and shoot growth. Wood formation stopped c. 4 weeks earlier at the xeric compared with the dry-mesic site in both years, indicating a strong influence of drought stress on cell differentiation. This is supported by radial widths of earlywood cells, which were found to be significantly narrower at the xeric than at the dry-mesic site (P analyses during the two growing seasons revealed that, although spatial variability in the dynamics and duration of cell differentiation processes in P. sylvestris exposed to drought is strongly influenced by water

  14. Xylem and Leaf Functional Adjustments to Drought in Pinus sylvestris and Quercus pyrenaica at Their Elevational Boundary

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    Laura Fernández-de-Uña

    2017-07-01

    Full Text Available Climatic scenarios for the Mediterranean region forecast increasing frequency and intensity of drought events. Consequently, a reduction in Pinus sylvestris L. distribution range is projected within the region, with this species being outcompeted at lower elevations by more drought-tolerant taxa such as Quercus pyrenaica Willd. The functional response of these species to the projected shifts in water availability will partially determine their performance and, thus, their competitive success under these changing climatic conditions. We studied how the cambial and leaf phenology and xylem anatomy of these two species responded to a 3-year rainfall exclusion experiment set at their elevational boundary in Central Spain. Additionally, P. sylvestris leaf gas exchange, water potential and carbon isotope content response to the treatment were measured. Likewise, we assessed inter-annual variability in the studied functional traits under control and rainfall exclusion conditions. Prolonged exposure to drier conditions did not affect the onset of xylogenesis in either of the studied species, whereas xylem formation ceased 1–3 weeks earlier in P. sylvestris. The rainfall exclusion had, however, no effect on leaf phenology on either species, which suggests that cambial phenology is more sensitive to drought than leaf phenology. P. sylvestris formed fewer, but larger tracheids under dry conditions and reduced the proportion of latewood in the tree ring. On the other hand, Q. pyrenaica did not suffer earlywood hydraulic diameter changes under rainfall exclusion, but experienced a cumulative reduction in latewood width, which could ultimately challenge its hydraulic performance. The phenological and anatomical response of the studied species to drought is consistent with a shift in resource allocation under drought stress from xylem to other sinks. Additionally, the tighter stomatal control and higher intrinsic water use efficiency observed in drought

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

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    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

  16. Assessing conifer ray parenchyma for ecological studies: pitfalls and guidelines

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    Georg evon Arx

    2015-11-01

    Full Text Available Ray parenchyma is an essential tissue for tree functioning and survival. This living tissue plays a major role for storage and transport of water, nutrients and non-structural carbohydrates (NSC, thus regulating xylem hydraulics and growth. However, despite the importance of rays for tree carbon and water relations, methodological challenges hamper knowledge about ray intra- and inter-tree variability and its ecological meaning. In this study we provide a methodological toolbox for soundly quantifying spatial and temporal variability of different ray features.Anatomical ray features were surveyed in different cutting planes (cross-sectional, tangential, and radial using quantitative image analysis on stem-wood micro-sections sampled from 41 mature Scots pines (Pinus sylvestris. The percentage of ray surface (PERPAR, a proxy for ray volume, was compared among cutting planes and between early- and latewood to assess measurement-induced variability. Different tangential ray metrics were correlated to assess their similarities. The accuracy of cross-sectional and tangential measurements for PERPAR estimates as a function of number of samples and the measured wood surface was assessed using bootstrapping statistical technique. Tangential sections offered the best 3D insight of ray integration into the xylem and provided the most accurate estimates of PERPAR, with 10 samples of 4 mm2 showing an estimate within ±6.0% of the true mean PERPAR (relative 95% confidence interval, CI95, and 20 samples of 4 mm2 showing a CI95 of ±4.3%. Cross-sections were most efficient for establishment of time series, and facilitated comparisons with other widely used xylem anatomical features. Earlywood had significantly lower PERPAR (5.77 vs. 6.18% and marginally fewer initiating rays than latewood. In comparison to tangential sections, PERPAR was systematically overestimated (6.50 vs. 4.92% and required approximately twice the sample area for similar accuracy. Radial

  17. Predictive Modeling of Black Spruce (Picea mariana (Mill. B.S.P. Wood Density Using Stand Structure Variables Derived from Airborne LiDAR Data in Boreal Forests of Ontario

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    Bharat Pokharel

    2016-12-01

    Full Text Available Our objective was to model the average wood density in black spruce trees in representative stands across a boreal forest landscape based on relationships with predictor variables extracted from airborne light detection and ranging (LiDAR point cloud data. Increment core samples were collected from dominant or co-dominant black spruce trees in a network of 400 m2 plots distributed among forest stands representing the full range of species composition and stand development across a 1,231,707 ha forest management unit in northeastern Ontario, Canada. Wood quality data were generated from optical microscopy, image analysis, X-ray densitometry and diffractometry as employed in SilviScan™. Each increment core was associated with a set of field measurements at the plot level as well as a suite of LiDAR-derived variables calculated on a 20 × 20 m raster from a wall-to-wall coverage at a resolution of ~1 point m−2. We used a multiple linear regression approach to identify important predictor variables and describe relationships between stand structure and wood density for average black spruce trees in the stands we observed. A hierarchical classification model was then fitted using random forests to make spatial predictions of mean wood density for average trees in black spruce stands. The model explained 39 percent of the variance in the response variable, with an estimated root mean square error of 38.8 (kg·m−3. Among the predictor variables, P20 (second decile LiDAR height in m and quadratic mean diameter were most important. Other predictors describing canopy depth and cover were of secondary importance and differed according to the modeling approach. LiDAR-derived variables appear to capture differences in stand structure that reflect different constraints on growth rates, determining the proportion of thin-walled earlywood cells in black spruce stems, and ultimately influencing the pattern of variation in important wood quality attributes

  18. Wood Anatomy and Insect Defoliator Systems: Is there an anatomical response to sustained feeding by the western spruce budworm (Choristoneura occidentalis) on Douglas-fir (Pseudotusga menziesii)?

    Science.gov (United States)

    Axelson, Jodi; Gärtner, Holger; Alfaro, René; Smith, Dan

    2013-04-01

    ), cell wall thickness (µm), lumen diameter (µm), and total cell width (µm) were measured. Preliminary results indicate that earlywood parameters remain quite stable during WSB outbreak, while latewood parameters such as secondary cell wall thickness and cell length undergo step shifts at the beginning and end of outbreaks. These parameters, tree-level data, and annual defoliation data will further be tested to determine if changes in stem wood anatomy during WSB outbreaks were statistically significant.

  19. Growth Response of Silver Fir and Bosnian Pine from Kosovo

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    Elvin Toromani

    2010-06-01

    Full Text Available Background and Purpose: This paper explore the growth-climate relationships in total ring width chronologies of silver fir (Abies alba Mill. and Bosnian pine (Pinus heldreichii Christ. The objective of this study is to quantify the climate influence on radial growth of both species. The relationships between climate and ring widths were analyzed using extreme growing years (called pointer years, simple correlations and response functions analysis (bootstrapped coefficients. The objectives of this study were: (1 to define the pattern of climatic response of each species, (2 to highlight the influence of local ecological conditions on tree's growth, and (3 to compare the response of silver fir and Bosnian pine to climate. Responses of total ring width to climate were estimated by establishing the mean relationship between growth and climate through simple correlations analysis and bootstrapped response functions. The response to climatic variability was also assessed by analyzing pointer years which correspond to abrupt changes in growth pattern and revealing the tree-growth response to extreme climatic events. For the period 1908-2008 the mean sensitivity (MS of total ring width chronology for Bosnian pine (0.209 was higher than silver fir (0.169 suggesting that Bosnian pine is more sensitive to climate (pointer years were more frequent in ring width chronology of Bosnian pine than in silver fir ring width chronology. The high values of first-order autocorrelations for Bosnian pine (0.674 indicated a strong dependence of current growth on the previous year’s growth. Pointer years analysis underlined the high sensitivity to spring temperatures and precipitation for both species. Radial growth for both species depends strongly on spring climate variables (temperatures and precipitation which play a significant role particularly for earlywood production. Material and Methods: We selected 12 silver fir trees and 15 Bosnian pine trees and took two 5

  20. 13C-derived water use efficiency in Mediterranean pines across a precipitation gradient are related to differential moisture-dependant Ci-regulation responses.

    Science.gov (United States)

    Maseyk, Kadmiel; Hemming, Debbie; Angert, Alon; Leavitt, Steven; Yakir, Dan

    2010-05-01

    Persistent predictions of warming and drying in the entire Mediterranean and other regions motivate investigation of terrestrial ecosystem responses to such change. We have used 30 year (1974-2003) records of tree-ring derived growth measures (basal area increment, BAI) and cellulose 13C isotopic composition from three sites across a geographical rainfall gradient to explore the temporal behaviour and physiological responses to variations in climatic (rainfall, temperature) and atmospheric ([CO2], Ca) drivers in Pinus halepensis trees. Potential juvenile effects on the cellulose 13C record were negligible in the two even-aged low density stands and excluded from the mixed-aged natural stand. Agreement between estimates of intrinsic water use efficiency (Wi) from cellulose 13C values and leaf-scale gas exchange measurements, consistency across the sites in the Wi response to soil water content and an observed insensitivity to known thinning events at the dry site give us confidence that leaf-level physiological responses, and not age and density effects, dominate the 13C isotopic record in these trees. Site-level differences and inter-annual variations in the earlywood (EW, associated with the wet and productive period) 13C-derived estimates of Wi were related to annual precipitation in a common, site-independent manner, with reduced sensitivity to annual rainfall above ~600mm. Rainfall was also the predominant driver in inter-annual variations in BAI. While there were no trends in rainfall amount over this period, there were clear trends of increasing Wi in both the EW and latewood (LW) that ranged between ca. 5 and 20% increase over the study period. These trends were better correlated with the increase in Ca than a temperature increase (~0.04°C y-1)that was also observed across the sites. The different sensitivities of Wi to Ca (dWi/dCa of 0.1 to 0.5 umol mol-1 ppm-1) represented shifting Ci-regulation (Ci, leaf internal CO2 concentration) responses associated

  1. 大兴安岭北部樟子松树轮δ13C的高向变化及其与树轮宽度的关系%Vertical variability of Pinus sylvestris var.mongolica tree ring δ13C and its relationship with tree ring width in northern Daxing' an Mountains of Northeast China

    Institute of Scientific and Technical Information of China (English)

    商志远; 王建; 张文; 李彦彦; 崔明星; 陈振举; 赵兴云

    2013-01-01

    A measurement was made on the vertical direction tree ring stable carbon isotope ratio (δ13C) and tree ring width of Pinus sylvestris var. mongolica in northern Daxing' an Mountains of Northeast China, with the relationship between the vertical direction variations of the tree ring δ13 C and tree ring width analyzed. In the whole ring of xylem, earlywood ( EW) and bark endodermis, the δ13C all exhibited an increasing trend from the top to the base at first, with the maximum at the bottom of tree crown, and then, decreased rapidly to the minimum downward. The EW and late-wood (LW) had an increasing ratio of average tree ring width from the base to the top. The average annual sequence of the δ13 C in vertical direction had an obvious reverse correspondence with the av-erage annual sequence of tree ring width, and had a trend comparatively in line with the average an-nual sequence of the tree ring width ratio of EW to LW above tree crown. The variance analysis showed that there existed significant differences in the sequences of tree ring δ13C and ring width in vertical direction, and the magnitude of vertical δ13C variability was basically the same as that of the inter-annual δ13C variability. The year-to-year variation trend of the vertical δ13C sequence was approximately identical. For each sample, the δ13C sequence at the same heights was negatively correlated with the ring width sequence, but the statistical significance differed with tree height.%通过对大兴安岭北部樟子松树轮样品高向的年轮宽度和稳定碳同位素比率(δ13C)进行测定,分析了高向上δ13C的变化特征及其与年轮宽度的关系.结果表明:在木质部全轮、早材和树皮内皮3种成分中,样品高向δ13C均呈现由顶部至基部先显著增加,在冠层底部达到最大值,再向下迅速减少至谷值的变化趋势.早晚材平均宽度比由基部至顶部增大.高向上δ13C年均值序列与轮宽年均值序列呈现较为明显的

  2. July Temperature at the Upper Treeline Recorded in the Tree-Ring in the Headwaters of the (U)rümqi River%树轮记录的过去384a乌鲁木齐河源7月温度变化

    Institute of Scientific and Technical Information of China (English)

    陈峰; 袁玉江; 魏文寿; 王丽丽; 喻树龙; 李杨; 张瑞波; 范子昂

    2011-01-01

    Using tree rings of Picea schrenkiana sampled from the upper treeline in the headwaters of the (U)rümqi River, 21 tree-ring density series were developed, and then the earlywood density (EWD) chronology was established. Analyzing the characteristics of the chronologies and their respond to climate factors, the EWD chronology was found that correlates at 0. 651 with the anomaly of maximum mean temperature in July over the period 1959-2006, which explained 42.4% of the variance in the reconstruction (F = 33. 805, P < 0. 0001). According to the temperature reconstruction in the headwaters of the (U)rümqi river, the anomaly of mean maximum temperature over the period 1623-2006 was 0. 37 C. The temperature reconstruction has a good response to the history records, temperature reconstructions from treering and glacial chgnge. The results reveal the common climatic extremes and climate change over Northwest China. Many of these events have had profound impacts on the peoples over the past several centuries, for example the 1640s great drought. Multitaper spectral analysis indicates that there were some low-and high-frequency cycles with the periods of 192 a, 29.3 a, 6.8 a, 4.3 a, 4 a, 3.7 a, 2.3 a and 2.1 a. Abrupt change of temperature occurred in 1645, 1665, 1726, 1807,1833, 1855, 1878, 1929 and 1954.%利用采自乌鲁木齐河源上树线跃进桥东采样点的雪岭云杉树轮样本,分析了其年表特征和气候响应特点.结果表明:采样点树轮早材密度标准化年表与和大西沟气象站7月份平均最高温度具有很好的正相关关系.用跃进桥东采样点的早材密度标准化年表序列,可较好地重建乌鲁木齐河源1623-2006年的7月平均最高温度,1959-2006年48 a重建值对实测值的解释方差达42.4%,交叉检验表明重建结果是稳定可靠的.近384 a来乌鲁木齐河源7月平均最高温度距平平均值为0.37℃.乌鲁木齐河源近384 a的7月平均最高温度经历了5个偏暖阶段和4个

  3. Fenología del anillo de crecimiento de Pinus uncinata Ramond y Pinus sylvestris L. en un gradiente altitudinal en los Pirineos Centrales

    Directory of Open Access Journals (Sweden)

    Camarero, J. Julio

    1996-12-01

    Full Text Available In this study, we describe tree-ring growth and structure of Pinus uncinata Ram. and Pinus sylvestris L. along an altitudinal gradient in the Central Pyrenees. We measured monthly ring width increase and the number of cells added during 1993. Both species formed most of the ring from mid june to mid July 1993. Latewood development -formation, darkening and lignification of cell walls- starts in July and ends in October. The ring begins before its development in P. sylvestris than in P. uncinata that lives at higher elevation. P. uncinata formed narrower rings with less cells and greater color heterogeneity in the latewood than P. sylvestris. There is a high variability between trees in the earlywood and latewood cells position in the ring. The different phenological patterns of tree-ring growth along the selected altitudinal gradient could be partially explained by the influence of different climatic conditions, mainly thermic.

    [es] En el presente trabajo, describimos el desarrollo y la estructura del anillo anual de crecimiento de Pinus uncinata Ramondy Pinus sylvestris L. en un gradiente altitudinal en los Pirineos centrales. Medimos mensualmente el aumento de la anchura del anillo y el número de traqueidas añadidas a lo largo de 1993. En ambas especies, la mayor parte del anillo se forma desde mediados de jimio hasta mediados de julio de 1993. El desarrollo de la madera tardía -formación, coloración y engrasamiento y lignificación de las paredes celulares- comienza en julio y acaba en octubre. El anillo comienza antes su formación en los bosques estudiados de P. sylvestris que en P. uncinata, el cual vive a mayor altitud. P. uncinata forma anillos más estrechos, con menor múmero de células y con mayor heterogeneidad de color de la madera tardía que P. sylvestris. Existe una gran variabilidad entre árboles en la posición de las células de

  4. Linkage between instrumental, documentary and dendrochronological data in the last millennium for long-time climate and flood dynamic reconstructions

    Science.gov (United States)

    Schoenbein, J.; Land, A.; Glaser, R.; Friedrich, M.; Riemann, D.; Kueppers, M.

    2009-04-01

    anomalies, which indicate a strong flood event, represent a climate proxy which - for the first time - offers insight into the climatologically character of the winter season if the event can bee understood as a result of the melting snow in spring. Additional information about river discharge during spring can be derived from vessel sizes within the growth-rings. In order to establish a climate model, which is based on the proxy data provided by the HOC Hohenheim, the growth response of living oak trees in riverine forests of the Main valley has been analyzed for the period of instrument measurement data (1880 - today). The tree-ring behaviour of several tree-ring variables relating to climate and flood dynamics were measured and statistically compared to high resolution climate and environmental data (e.g. temperature, precipitation, sea surface pressure, groundwater level, river discharge or floods). High significant correlations were found for the latewood width (LWW), mean area of the five largest vessels (MVA5), conductive earlywood area (CEA) and the total mean vessel area (TMVA). These tree-ring variables contain high resolution climate signals of river discharge in June to August (LWW), air temperature in February and April (MVA5) and river discharge in April to May (CEA, TMVA). Wood anatomical anomalies ('flood markers'), preserving high-magnitude flood signals (spring/summer), are used to verify severe precipitation anomalies. The climate dataset derived from documentary data allows for testing the found seasonal grow-to-climate-relations to a longer period of time (1400 - 1800 A.D.). The high temporal resolution in combination with the fact, that (growth-sensitive) climate extremes are best covered in documentary data, makes the joining of these two climate archives promising. First tests of selected growth parameters show highly significant, however moderate statistically relation. The descriptions of climatologically relevant concomitants laid down in the

  5. 杂种落叶松F2代自由授粉家系纸浆材遗传变异及多性状联合选择%Genetic Variations in Pulpwood Qualities of F2 Generation of Open-Pollinated Larch Hybrid Families and Multi-Traits Selection

    Institute of Scientific and Technical Information of China (English)

    邓继峰; 张含国; 张磊; 朱航勇; 贯春雨

    2011-01-01

    results showed that there were variations within the families as well as between families. Latewood had greater coefficient of variation than earlywood. There were abundant variations in the volume, tracheid length-width ratio,resin canal proportion and the coefficients of variation were between 26. 2% - 85.3%. There was small variation in the Holo cellulose (HC), early wood microfibrillar angle (MFA) and tracheid proportion and the coefficients of variation were between 1.4% -8. 1%. There were significant differences in HC, early wood and latewood MFA, tracheid length-width ratio, latewood radial diameter, latewood cell wall ratio, latewood tracheid wall thickness-diameter ratio and tracheid proportion between treatments. There were differences in volume, tracheid length, tangential diameter, early wood and latewood number of cells per square millimeter between treatments. The family heritability were between 59.3% -92.7%, suggesting that these traits had potential for pulpwood selection. There was significantly positive correlation between volume and HC, and there were positive correlations between volume and MFA, tangential diameter, late wood tracheid wall thickness-diameter ratio and tracheid proportion, while there was negative correlation between tracheid length-width ratio and late wood number of cells per square millimeter. Correlations were negatively high between basic density and volume, significantly negatively high between basic density and HC, positively high between basic density and tracheid length-width ratio, early wood MFA, latewood number of cells per square millimeter, negatively high between HC and late wood number of cells per square millimeter, significantly negatively high between tracheid length-width ratio and late wood cell wall ratio, and significantly positively high between early wood MFA and tracheid proportion. Ⅰ3, Ⅰ4, and Ⅰ9 were the idealist index. Based on growth and wood traits, 3 families were selected for pulpwood