Tree-ring Patterns Research Articles

Leño y corteza de Prosopis alba Griseb., algarrobo blanco, Mimosaceae, en relación con algunas magnitudes dendrométricas

Prosopis alba Griseb., is one of the most important Argentinean Mimosaceae. With a great distribution area, it is a common component in the Chaco Forest. Prosopis alba, Algarrobo blanco, is one of the Argentina's legumes of more economic importance. The aims of this study are: to describe the wood and bark anatomy and tree ring pattern of Prosopis alba, to analyse tree ring evolution in relation to age and orientation, to characterise sapwood, heartwood and bark width, in relation to age, DBH (diameter at breast height) orientation, and height and to determine the main defects of the wood. The study was carried out in ten individuals from the following sites of Santiago del Estero, Argentina: Brea Pozo, San Martin Department; Las Delicias, Pellegrini Department and Sachayoj, Alberdi Department. Healthy, well formed trees, with more than 30 cm DBH were selected from the dominant-canopy. Wood samples were taken following the methodology of Helinska et al. The terminology by IAWA was used for wood descriptions, and the terminology by Roth in bark. Results obtained show that Prosopis alba has tree ring demarcated by terminal parenchyma (type 2 of Coster). Tree rings have a medium width of 4.05 mm (2.11-5.18), with a maxim between 29 and 32 years. Orientation had no influence on width. Sapwood in the trunk has a tree ring width (2-6), diminishing with age and height. The principal defect of the wood are the scars produced by fire which alter the pattern of growth. The deciduous bark is of the fibrous type, with longitudinal fissures. The thickness of total bark is 1.16 cm, the living bark 0.39 cm and rhytidome 0.74 cm. The bark increases with age and diminishes with DBH. The duraminization process begins between the years 3 to 6.

LANDSCAPE CHANGE FOLLOWING DEFORESTATION AT THE ARCTIC TREE LINE IN QUÉBEC, CANADA

This study examines the influence of fire-induced deforestation in well- drained conifer sites on the development of adjacent, surviving spruce stands in peatlands at the arctic tree line (northern Quebec). Tree-ring and growth-form patterns of cross-dated black spruce (Picea mariana) remains in peat were used to analyze stand responses in two contrasting topographical settings: a moderately protected valley-bottom peatland, and an exposed hilltop peatland. Dense, old-growth spruce populations occupied the studied peat- lands between the 11th and 16th centuries, with stunted and erect spruce dominating the hilltop and the valley sites, respectively. Spruce continued to colonize the peatlands as long as the adjacent well-drained sites were occupied by forest trees able to attenuate the dam- aging effect of winter snow-drifting conditions. The surviving conifer stands exhibited similar growth responses following deforestation of the well-drained sites by wildfire in AD 1567-1568. These responses included dieback of supranival (above snow) stems and death of trees due to drowning in permafrost-induced ponds. The postfire degradation and disappearance of the conifer stands from the peatlands were the ultimate stage of a positive feedback process triggered by a modification of the snow regime at the landscape scale. Deforestation of the well-drained sites led to reduced snow accumulation and enhanced snow-drift exposure, thus inducing permafrost aggradation and drainage impediment in the nearby peatland sites. While the hilltop conifer stand responded immediately to forest exclusion in the nearby sites, ecosystem changes in the valley peatland were delayed until AD 1580-1590, at the beginning of the Little Ice Age. Our results emphasize the sensitivity and connectedness of adjoining ecosystems to fire and frost disturbances in a changing subarctic landscape mosaic.

A dendroecological assessment of whitebark pine in the Sawtooth–Salmon River region, Idaho

Whitebark pine (Pinusalbicaulis Engelm.) tree-ring chronologies of 700 to greater than 1000 years in length were developed for four sites in the Sawtooth–Salmon River region, central Idaho. These ring-width chronologies were used to (i) assess the dendrochronological characteristics of this species, (ii) detect annual mortality dates of whitebark pine attributed to a widespread mountain pine beetle (Dendroctonusponderosae Hopkins (Coleoptera: Scolytidae)) epidemic during the 1909–1940 period, and (iii) establish the response of whitebark pine ring-width growth to climate variables. Cross-dating of whitebark pine tree-ring patterns was verified. Ring-width indices had low mean sensitivity (0.123–0.174), typical of high-elevation conifers in western North America, and variable first-order autocorrelation (0.206–0.551). Mountain pine beetle caused mortality of dominant whitebark pine peaked in 1930 on all four sites. Response functions and correlation analyses with state divisional weather records indicate that above-average radial growth is positively correlated with winter and spring precipitation and inversely correlated with May temperature. These correlations appear to be a response to seasonal snowpack. Whitebark pine is a promising species for dendroclimatic studies.

14C and 90Sr measurements at the Erlangen AMS facility

The AMS beamline at the Erlangen EN tandem accelerator has been completed and improved. The high-current Cs sputter ion source has been finished and is being used mainly with carbon and SrF 2 samples. Sample exchange is done by remote control, under high voltage and without breaking the vacuum. Fast isotope switching is performed by applying high voltage pulses of adjustable length at the chamber of the 90° injection magnet, which can be used for different kinds of ions and beam currents. Using a new 120° magnetic split-pole spectrograph, 90Sr was measured at isotopic ratios 90Sr/ 88Sr between 10 −9 and 10 −8 for environmental applications. Radiocarbon dating of samples along the cross section of tropical trees yielded information about the growth rhythms of the tropical wood, which are difficult to determine because of missing tree ring patterns.

Spatial Patterns of Climate and Tree Growth Variations in Subtropical Northwestern Argentina

In order to gain an understanding of the spatial connections between instrumental and proxy climatic data in subtropical regions, we investigated the spatial patterns of climate and tree-growth anomalies in the montane forests of northwestern Argentina. Principal components technique was used to identify the dominant spatial patterns of climate and tree growth anomalies. A 43-year data set of monthly total precipitation at a selected network of thirty- one stations in northwestern Argentina was analysed on annual and seasonal basis. The most dominant annual pattern shows precipitation anomalies of the same sign over practically the whole area. The second and third patterns reflect altitudinal and latitudinal rainfall variations across the study area, respectively. The tree-ring data set consisted of twelve chronologies developed from Juglans australis Griseb., Cedrela angustifolia Sesse Moc., and Cedrela lilloi C.DC. The relationships between climatic conditions, site characteristics, and tree-ring growth were identified using response functions, correlation functions, and group analysis. These techniques show that tree ring widths in subtropical Argentina are affected by weather conditions from late winter to early summer. Tree-ring patterns mainly reflect the direct effects of the principal types of rainfall patterns observed, the first in which rainfall conditions are uniform across the study area, and the third in which pre- cipitation anomalies are concentrated in the northeastern part of the region. Finally, different regression models were used to reconstruct annual and seasonal variations in pre- cipitation. On average, 60-80% of the variance in regional precipitation is explained using the ring-width chronologies as predictive variables.

Disturbance regime of a cold temperate forest as deduced from tree-ring patterns: the Tantaré Ecological Reserve, Quebec

The recent history and disturbance regime of an old-growth sugar maple – yellow birch forest located in the Tantaré Ecological Reserve, Québec, were determined using tree-ring growth patterns of individual trees that had undergone suppression and release. Within a sampling quadrat (0.25 ha) where all living and dead trees were mapped, the age, size, and spatial pattern of gaps formed since the mid-19th century were inferred from tree-ring signatures of standing trees. From 1860 onwards, more than 30 gaps of various form and size occurred, most gaps being < 200 m2 and covering a total area of 3775 m2. During the 1930–1985 period, the tree-fall frequency was 0.45 per year, the tree fall free interval was 3.2 years, and the tree-fall rotation period (turnover rate) was estimated to be 45 years. The rather short life-span of most trees (<125 years) may be attributed to the cool and humid conditions prevailing at the site, which stimulated self-pruning of mature trees. The spatiotemporal development of the sugar maple forest has been active during the past 2 centuries through small-scale disturbances associated with successve, often overlapping, single and multiple tree falls. This situation explains the uneven age distribution of sugar maple and yellow birch populations subjected to differential survival conditions caused by gap dynamics. It is concluded that tree-ring patterns corresponding to periods of suppression and release will likely give a finer resolution record of gap dynamics than other methods of determining natural disturbance regime and reconstruction of recent stand history.

Dendroecological evidence of lake-level changes during the last three centuries in subarctic Québec

Dendroecological analysis of black spruces ( Picea mariana (Mill.) BSP.) near the shore of Clearwater Lake in the eastern Canadian subarctic yielded information on water level over the past three centuries. Tree positions, growth froms, layering, tree ring patterns, and ice scars provide direct evidence of a major rise in lake level. From the 17th century to the present, trees on the lake shore were progressively submerged by the increasing water level, which reached a maximum in this century. Higher levels began around the mid-18th century when shoreline spruce trees started to lean because extensive wave erosion caused landward shore displacement. High mortality of leaning spruce and abundant ice scar formation occurred during this century. The rise in water level in inferred to have been caused by snowier winters occurring parallel to climatic warming.

Nodular Remains of Early Tertiary Forests, Bighorn Basin, Wyoming

Orange calcareous nodules are widespread in Lower Tertiary alluvial paleosols in the Bighorn Basin, Wyoming. The nodules are abundant at specific stratigraphic levels where they form distinctive and laterally extensive bands. Many are preserved as erect, crudely shaped cylinders a few centimeters to more than 1 m high and generally 10-30 cm in diameter. At two stratigraphic levels in the sequence, hands of cylindrical nodules occur in close association with upright and well-preserved fossil tree stumps. The stumps, which show a distinctive tree-ring growth pattern, are orange in color and permineralized with calcite. The physical proximity and morphologic similarities between the calcified tree stumps and calcareous nodules suggest that the nodules are simply additional, albeit more poorly preserved, tree stumps. Their widespread occurrence in specific horizons suggests that the nodules are the remains of Tertiary forests that grew on stable land surfaces. Although fossil forests can be readily recognized by the presence of upright permineralized trees, such occurrences are rare. The nodular horizons described here provide a new means of determining the location and stratigraphic position of ancient forests.

Dendroecological Studies in the Front Range, Colorado, U.S.A.

Two dendroecological procedures are described. The first involves the radiodensitometric analysis of conifer material from an altitudinal transect between the subalpine and the lower, arid timberline. Core samples were taken from selected stands with very differing site conditions at three altitudes, and tree-ring parameters including maximum latewood density, latewood width, and total width were measured. A special type of diagram was developed to assist analysis of the complex relationships between tree-ring growth, weather, and site conditions on a year-for-year basis. This is a departure from the conventional approach of analyzing only mean relationships over long time sequences. An advantage of the elaborated singleyear method is that the growth models are allowed to vary with time. Typical cases are illustrated, and the dynamics of the overlapping influences of weather and site conditions are discussed. The second procedure comprises the visual identification and dating of abrupt, persistent changes in the tree-ring pattern and their relation to biotic and abiotic factors. This allows the reconstruction of insect attacks, forest fires, and forest clearing.

New evidence for the dendrochronological dating of Netherlandish paintings

The authors elaborate on a recent paper by Baillie et al. (See AATA 22-1966 for abstract of article) which resolved a number of problems in art-historical dendrochronology. They remark that analysis of oak panels used by Rembrandt, Rubens, and other painters between the 14th and the middle of the 17th centuries revealed a new tree ring pattern not cross-matching with any of the existing oak chronologies. They undertook a study of building timbers from churches and other historical buildings and excavated artifacts in North Poland around Gdansk and were able to confirm one of the two tree ring chronologies existing for the Netherlands. The statistical data of concordance are detailed. A table summarizes the dating of 10 Rembrandt paintings. Dating of other identified art objects are presented as unaffected by these findings.

Contribution of Tree-Ring Dating and Wood Structure Analysis to the Forensic Sciences

ABSTRACTThe basic concepts of tree growth, tree-ring dating, wood anatomy, wood and wood-fiber species identification have been described as potentially useful tools to the forensic scientist. Eight case studies have been presented to help crime-scene investigators recognize the value of wood in the hands of a specialist. The case studies have dealt with (i) linking a suspect to a crime scene by using species identification and through physical matching of tree-ring patterns and anatomical features, and (ii) dating a crime or a past event to the calendar year and/or the growing season.

CONSIL 906

Abstract CONSIL 906 is an internally oxidized silver-cadmium oxide alloy for electrical contact applications. It has extremely small cadmium oxide particles, desirable for long contact life. The particles exhibit a tree-ring pattern, a characteristics of the multiple oxidation production process. Careful control of the oxidation process results in negligible cadmium oxide depletion of the core or surface. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion resistance as well as forming and heat treating. Filing Code: Ag-10. Producer or source: Handy & Harman.

Dendrochronological Evidence of Variations of Coleman Glacier, Mount Baker, Washington, U.S.A.

Coleman Glacier is situated on the ice-clad Mount Baker volcano in the Pacific Northwest of North America. It is fronted by several forested terminal moraines, minimum ages of which have been determined by tree-ring counts. Nine of the 150 conifers studied were trees damaged by glacial advances; others were the oldest trees found on the moraines themselves. The treering patterns of the former set of conifers revealed the years when glacier readvances reached their maxima, whereas the number of tree rings in the latter group only provided minimum ages for moraine stabilization. Together with historical records, the tree-ring counts date moraines to the following years: 1978-79, ca. 1922, ca. 1908-12, 1886-87, ca. 1855-56, ca. 1823, ca. 1740, and the early 1500s. Excluding the last two dates, the ages date the maximal glacier readvances relatively closely. The moraine chronology over the past two centuries developed for Coleman Glacier has great similarity to chronologies on Mount Rainier, Washington, and in Scandinavia. Because of the short response time of Coleman Glacier to climatic changes, the obtained dates of glacial readvances are consistent with the climatic information available.

Evidence of Prehistoric Cultivation of Douglas-Fir Trees at Mesa Verde

AbstractThree trees which began growing in the 12th century lean in a manner not characteristic of neighboring Douglas-firs and have tree-ring patterns showing changes that do not appear to reflect climatic influences. Two old trees, now dead, have limb stubs that were cut by stone tools. It is possible the prehistoric Indians cultivated trees so that in a relatively short time a single root system would produce several limbs suitable for use as construction timbers.

Relationship of Southern Cedar Growth to Precipitation and Run Off

Interest in tree ring studies by the Douglass method might be said to have focused principally on four fields of contact:-archaeology, botany, meteorology, and astronomy, although, as a new science, dendrochronology contacts, uses, and eventually may add some data to the libraries of accumulated knowledge catalogued even for other sciences. Since he began the study in the first years of the twentieth century, Dr. Douglass' primary interests have been the reflection of astronomy and meteorology in tree growth: the effect of terrestrial conditions upon the annual increment of trees over a known recent period, and from that, the record of wet and dry periods as indicated by the tree ring records which extend centuries farther into the past than any human records. Definite identification of tree ring patterns covering sequences of years was found to be possible, and by matching the outer sequences of rings of older trees onto the inner sequences of modern specimens, by what has been called the bridge method, a record was compiled in which the year of every narrow and every wide ring was known, and onto which the growth record of roof beams from prehistoric Southwestern pueblos might be matched and their cutting dates thereby ascertained. This development was of great importance to southwestern archaeologists, for now instead of arguing over the probable century in which any pueblo was built, a beam from its ruins can be examined at the Douglass' laboratory and the year in which the tree which made the beam was cut may be identified.