Annual Growth Rings Of Trees Research Articles

CEREBELLAR CALCIFICATION DETECTED BY ALIZARIN RED S STAINING IN THIOPHENE-EXPOSED RATS

Repeated injections of thiophene induce vasogenic cerbellar degeneration and local calcium deposits in the cerebellar granule cell layer in rats. Using light and electron microscopy, we investigated the formation of cerebellar calcification between 1 hour and 40 days after thiophene administration. Alizarin red S staining was used on microslicer sections to demonstrate early pathological calcium deposition. In the cerebellum of rats that developed truncal ataxia and/or seizure, 1) pathological calcium deposits appeared in the granule cell layer and the deep cerebellar nucleus from the early stage, 2) the calcium deposits were lamellated like the annual growth rings of trees in the granule cell layer but had disappeared in the deep cerebellar nucleus at 40 days after thiophene administration, and 3) ultrastructurally, needle-like crystal deposits of calcium were found in the postsynaptic endings of the cerebellar glomeruli, perikarya of granule cells, axoplasm of myelinated fibers and presynaptic endings of deep cerebellar nuclei. It is suggested that the cerebellar calcification induced by thiophene is initiated in granule cells through an excitotoxic mechanism and/or disorder of calcium metabolism.

Analytical investigations of tree rings by laser ablation ICP-MS

Laser sampling inductively coupled plasma mass spectrometry has been used for the quantitative determination of trace elements to characterize annual growth rings of trees. The elements studied are Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Cd, Ba, Tl, Pb, Bi and U. Cellulose mixed with multielement standard solution pressed into pellets were used for the calibration. Using internal standardization with 12C the precision is typically better than 10% relative standard deviation. The limits of detection were limited by the purity of the cellulose. Analytical figures of merit and the analytical results are discussed in terms of environmental analysis.

Ibotenic acid-induced calcium deposits in rat substantia nigra. Ultrastructure of their time-dependent formation.

The excitotoxin ibotenic acid (IBO) induces local calcium deposits upon injection into rat substantia nigra. Their formation has been investigated at the ultrastructural level in a time course study from 2 days to 8 weeks survival. Potassium bichromate stain was used to visualize pathological calcium accumulation. Two days after IBO application, reaction product for calcium was observed in mitochondria of degenerating perikarya and dendrites, but not in axons, boutons or glia. Four days after the lesion, calcium stain was found, in addition, in a seemingly free form in a few dendrites, especially those still contacted by intact boutons and not sequestrated by invading glia. Two days later, most of these calcium-accumulating dendrites were separated by astroglia from their synaptic partners. At the border between glia and dendrite a fibrillar matrix was formed which further accumulated calcium. During the following weeks this matrix enlarged stepwise and was infiltrated with calcium, thus giving a picture resembling the annual growth rings of trees. The evolving bodies incorporated smaller deposits in their vicinity, finally representing the large concretions seen at the light microscopic level from the 4th postoperative week onward. Similarities and dissimilarities of these observations with the results from other ultrastructural studies on excitotoxin lesions are detailed. It is suggested that the different outfit of neuronal subpopulations and of glia with ligand-gated and metabotropic glutamate receptors in the single brain region, as well as the local response repertoire of glial cells towards the excitotoxic injury with the subsequent formation of a calcium-accumulating matrix provide the molecular basis for the formation of calcium deposits.

Estimating Douglas-fir wood production from soil and climate data

The relationships between annual tree-ring growth and growing season climate were explored, studying 70-year-old coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees in three sites of different moisture microclimates within productive forest lands. Climate data were augmented via a water balance model to calculate soil moisture deficits. Eleven ring variable components were derived via X-ray densitometry for each ring from two cores for each of 10 trees per site. First principal component scores of each ring variable were linked to climate variables (from 1951 to 1985) via multiple regression. Annual water deficit was found to account for 51% of the annual variations in ring weight. Earlywood width showed little direct climate response, and earlywood density was the least variable ring component. Latewood width was related to annual water deficit (r2 = 0.47). Latewood density showed different relationships to climate variables at the different sites. Percent latewood is increased by spring rainfall and depressed by high August temperatures. The ranges between minimum to maximum and earlywood to latewood densities were comparable for all sites, indicating that there is little density variation due to site differences.

Verification of Annual Growth Rings in Egyptian Trees by C-14 Method

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

PIXE: A tool for research and education

The advantages of PIXE as an analytical tool are well known but the suitability of the method as an excellent educational tool for the training of students in research may not be as widely appreciated. This paper will demonstrate the latter attribute by describing research projects involving undergraduate students. The projects include PIXE analysis of: blood serum, annual-growth rings in trees, rainwater, and carbon water filters.

Dendrochronology In Plains Prehistory: An Assessment

Chronologies and climatological interpretations based upon annual growth rings of trees have been available to prehistorians within the Plains for more than half a cen tury. Until the advent of radiocarbon dating, tree rings provided the only absolute chronology for most arche ological complexes and subsequently, continued as an important adjunct to radiometric methods. Nonetheless, the validity of tree ring dates in the Plains must be ques tioned. Continuity of research has been lacking, there have been serious methodological problems, and the pro venience of many specimens is in doubt. Moreover, there are significant conflicts between tree ring and recent radiocarbon dates.

The potential of tree-ring analysis for monitoring heavy metal pollution patterns

The precise measurement of heavy metal levels within successive annual growth rings of trees presents, at first sight, an attractive and straightforward means for producing a detailed history of heavy metal pollution. However, before serious consideration is given to such a technique, many processes relating to the uptake, transport and deposition of heavy metals within trees must be understood. A brief survey of the pathways of metal uptake into trees is made, and consideration given to the external and internal factors which may operate in regulating metal entry. As the transport of metals within the tree is important, both pathways of metal transport, and the forms taken by metals during transport, are described. The regulation and patterns of metal deposition are fully considered, and emphasis is placed on internal factors which may regulate the rate of deposition, and the quantity of metal deposited, in a particular annual growth ring. The problem of possible lateral movement of metals between growth rings is also considered. Finally, conclusions are drawn regarding the potential of tree-ring analyses for producing pollution histories.

ANOMALY PATTERNS OF CLIMATE OVER THE WESTERN UNITED STATES, 1700–1930, DERIVED FROM PRINCIPAL COMPONENT ANALYSIS OF TREE-RING DATA

Major anomaly patterns of annual tree-ring growth in “drought-sensitive” trees of the Western United States, 1931–1962, seem to reflect corresponding patterns in monthly precipitation amounts, which in turn may be related to circulation anomalies. The three most important anomaly patterns that dominated the 1931–1962 period were also prominent in the tree-growth data during the preceding period 1700–1930. These patterns can thus be expected to maintain their importance during at least the immediate future. Time series of eigenvector amplitudes show how the relative importance of the anomaly patterns changes through time. These can be studied for properties lending possible forecasting value and may provide important insight into the past behavior of the atmospheric circulation over the Western United States.

Rainfall and Tree Growth in the Great Basin

IN recent years drought has become a major problem, in the western States, and it is important to study the variations of rainfall over as long a period as possible. In this region there are few rainfall stations with long records—scarcely any before 1871—and the author accordingly set out to supplement these with data from other sources, such as historical records of rains and droughts, crops, the levels of lakes and rivers and especially the annual growth-rings of trees

Tree Rings—The Archaeologist's Time-Piece

Since 1929 Southwestern archaeology has stood on a much surer footing than at any other time in the history of its development. This stabilization is due to the research of Dr. A. E. Douglass of Tucson, Arizona, whose inquiries into the reaction of trees to weather, from an astronomic standpoint, led, as a ramification, to the use of the annual growth rings in trees in dating the pre-Spanish remains of man in the Southwest. From the standpoint of the archaeologist, the most significant progress date in Dr. Douglass' study was June 22, 1929. On that day ended a long search for a particular sequence of rings needed to complete the ring record. This sequence was found in a log in the Showlow ruin, and united two chronologies then extant, the one a floating series of five hundred and eighty years, the other an historic series extending from 1929 to about 1280 A.D.