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1.
We present a network of thirteen annual ring-width chronologies from high elevation whitebark pine (Pinus albicaulis Engelm.) sites in the western Canadian Cordillera in order to assess the dendroclimatic potential of this long-lived tree species. The temperature signal within the chronologies is complex and strongly influenced by diverging trends in the summer temperature and ring-width records from across the region. A first differences transformation of the tree-ring and temperature records illustrates a loss of frequency coherence in growth response to summer temperatures following reduced radial growth in the 1950s. Prior to reduced growth, we note a positive association with summer temperatures for both first differenced (rd = 0.60) and traditional (r = 0.50) records. Following reduced growth, the association at first differences is maintained (rd = 0.49) whereas there is a change in the lower frequency component of tree growth response to summer temperatures (r = ?0.34). We suggest the cause of this reduced temperature sensitivity is related to the interaction between diurnal temperature and cloud cover patterns, the hydrological regime of snowpack, and site conditions which have been amenable to the initiation of moisture stress during the latter half of the 20th century. Reduced radial growth is coincident with the arrival of white pine blister rust (Cronatium ribicola J.C. Fisch. ex Raben) into the study region which suggests this infestation may be related to the observed reduction in radial growth. Whitebark pine has considerable potential for the field of dendroclimatology. Unfortunately, the decline of the species due to the combined effects of climate change, white pine blister rust, mountain pine beetle (Dendroctonus ponderosae Hopk.), and forest fire exclusion practices indicate this potential may remain unfulfilled. 相似文献
2.
《Dendrochronologia》2014,32(4):336-342
We used dendroarchaeological techniques to determine the year of construction of two historic structures in the Valles Caldera National Preserve of New Mexico, USA. Historical documents date some structures in the headquarters area of the Preserve, but the Commissary Cabin and Salt Barn were lacking conclusive construction dates. Both structures were originally thought to have been built by the Otero family who bought the property in 1899. We found that the structures were built from two tree species, white fir (Abies concolor (Gordon) Lindl. ex Hildebr.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), surprising given that ponderosa pines are also found in great numbers in the adjacent forest. Tree rings from 20 logs were confidently crossdated both graphically and statistically and provided cutting dates of trees in both structures of 1940 and 1941 when compared against the Fenton Lake reference chronology (Commissary Cabin: r = 0.69, t = 15.54, p < 0.0001, n = 263 years; Salt Barn: r = 0.77, t = 11.7, p < 0.0001, n = 232 years). By combining the cutting date years and terminal ring attributes, we suggest that both structures were built in the spring or early summer of 1941 using freshly cut logs and logs that had been cut the previous spring (1940, before or during the growing season) and stockpiled. The cutting dates of 1940 and 1941 indicate that these buildings were constructed during the Franklin Bond (1939–1945) era and associated with the transition from sheep ranching to more modern cattle grazing. These new dates provide a more distinct understanding of the cultural resources at the Valles Caldera National Preserve and provide interpretative staff with more accurate information that can be given to the public. 相似文献
3.
The Deason House is located in the heart of the Piney Woods region in the town of Ellisville, Mississippi. During the American Civil War, the Deason House became the epicenter for an event that started a rebellion against the Confederate government. On 5 October 1863, a Confederate deserter named Newton Knight allegedly shot and killed Confederate Major Amos McLemore in the Deason House, which eventually lead to the formation of the Free State of Jones. Despite the historical importance of the house, oral accounts and written documents have failed to provide accurate construction history of the structure. We coupled techniques of dendrochronology and geophysical survey to better understand the construction history of the Deason House and cultural activities of its inhabitants. We extracted 35 Pinus palustris (Mill.) timbers along the west-facing exterior weatherboards and from various logs within the second-floor attic, 25 of which were successfully crossdated against a P. palustris reference chronology located 15 km south in De Soto National Forest (1742–2013). The Deason House chronology anchored against the De Soto time series during the period 1742–1875 (r = 0.55, t = 4.01, p < 0.0001) and extended the reference chronology back to the year 1680 CE. Clustering of cutting- and near-cutting dates from timbers revealed 3 possible stages of construction. First, the house likely existed as a single-pen structure built in the winter of 1835/1836, based on two timbers with wane/bark that were affixed to the original chimney made of clay bricks fired on the homestead. Second, based on the clustering of 1855 cutting dates, we suggest this was the most likely time the original structure was expanded with a vestibule, porch, and larger 4-room house. Finally, six timbers revealed a back addition was constructed in the year 1866. Ground penetrating radar (GPR) helped provide evidence mentioned in written records that the back addition (1866) existed as the detached kitchen then was affixed to the structure ca. 1890. The GPR data revealed geophysical anomalies that indicated the original sites of the detached kitchen, water well, livestock pen, privies, and trash pit. Through the use of dendrochronological analyses and geophysical survey, we were able to provide an updated history of the Deason House construction dynamics and cultural activities of its inhabitants beyond the historical record. 相似文献
4.
Tree rings of eastern red cedar (Juniperus virginiana L.) were examined from cores extracted from two log cabins located at the Wynnewood State Historic Site in Castalian Springs, Sumner County, Tennessee. One cabin was reportedly built by the first explorer in the area, Isaac Bledsoe, sometime between 1772 and his death in 1793. The second cabin was known as Spencer's Cabin after the first settler of the region, Thomas Sharp Spencer, who lived in the immediate vicinity from 1776 to 1779. The goal of this research was to determine the probable construction year(s) for both cabins and determine whether Bledsoe and Spencer did indeed build these structures. Forty-one cores were extracted from Bledsoe's Cabin, and 30 were used for crossdating and building a floating chronology using COFECHA. The Bledsoe's Cabin chronology was then statistically and graphically crossdated using the eastern red cedar reference tree-ring chronology (ITRDB #TN031) from Norris Dam, Tennessee. We found a statistically significant correlation (r = 0.42, t = 4.18, n = 85, p < 0.0001) between the Bledsoe's Cabin chronology and the reference chronology, anchoring the chronology between 1720 and 1804, with nearly all cores indicating tree harvesting between February and April 1805. Twenty-two cores were extracted from Spencer's Cabin, and 17 were used to build a floating chronology for the cabin. Again, we found a statistically significant correlation (r = 0.44, t = 4.85, n = 100, p < 0.00001) with the reference chronology, which anchored the Spencer's Cabin chronology between 1726 and 1825. All trees appear to have been harvested between February and August in 1826. Therefore, neither structure was built by its historical namesake. No known historical documents suggest who the potential builders were, although the property was owned between ca. 1797 and 1829 by General James Winchester. He and his family, however, never resided on the Wynnewood property because Winchester had built a large multi-room structure in nearby Gallatin, Tennessee, by 1802. 相似文献
5.
《Dendrochronologia》2014,32(2):144-152
Tree-ring research in Ireland has typically been dominated by Quercus species, particularly Quercus petraea and Quercus robur. Recent years have seen a greater focus on multi-species reconstructions in Ireland but, due to difficulties with the hardness of the wood, missing/pinched rings and fused stems, Taxus baccata has not been included in these investigations. Despite these difficulties, a 31-tree, 204-year T. baccata chronology was successfully constructed from Killarney National Park, southwest Ireland. The chronology exhibits promising dendroclimatological potential, with climatic responsiveness equivalent to that of the other major Irish tree taxa, including Quercus. The chronology shows the strongest relationship with May–June precipitation from Muckross House synoptic station (1970–2007; r = 0.521, p < 0.01) and Valentia Observatory (1941–2007; r = 0.545, p < 0.01). November–April temperatures also exhibited a strong relationship with the chronology post-1970 (r = 0.605, p < 0.01 for Muckross House, r = 0.567, p < 0.01 for Valentia Observatory), but this relationship is not time stable and breaks down for the pre-1970 Valentia Observatory record. The long-lived nature of T. baccata, the exceptional preservation of wood and rings in this hard softwood species, as well as its prominence in Irish archaeology, all point to the potential to expand this chronology both spatially and temporally, and demonstrate T. baccata's potential in multi-site and multi-species tree-ring studies in the region. 相似文献
6.
Although long-lived trees grow in the Northern Caucasus, no single tree-ring chronology has been reported thus far from this area in the International Tree-Ring Data Base (ITRDB), neither has one been published in international journals. Extensive tree-ring studies were conducted over the last decade, and a tree-ring network was developed for the investigated area. The data on the minimum blue intensity based on 33 series of pine (Pinus sylvestris L.) and fir (Abies nordmanniana (Steven) Spach) is presented in this study. The minimum blue intensity (BI) chronology covers the period 1596–2011 with EPS value ≥0.85. The BI chronology strongly correlates with the mean June-September temperature (R = 0.74; p < 0.05) from the weather station “Kluhorskij Pereval” (1951–2011). Mean June-September temperature anomalies were reconstructed using the rescaling method. Based on the reconstruction provided in this study the twentieth century is characterized by highly increased June-September temperature. According to this study, the minimum blue intensity approach demonstrates a great potential for paleoclimatic research in the Caucasus. Vast spatial coverage of the new BI-based reconstruction based on data from only two locations in the Northern Caucasus provides prospects for reconstruction of temperature variations for a great region in the Middle East and Northern Africa. 相似文献
7.
The King site is a Late Mississippian (ca. 1400–1540 CE) aboriginal town located in northwestern Georgia along the Coosa River associated with the Coosa Chiefdom. The site was settled ca. 1530 but was occupied for perhaps only 50 years or so based on the lack of horizontal stratigraphy. The site was visited by members of either or both the Hernando de Soto expedition in 1540 and/or the Tristan de Luna expedition in 1560. In 1974, archaeologists discovered and removed 36 sections of subterranean charred pine posts from six house features. Our objectives were to determine if the tree rings on these posts could be dendrochronologically dated to verify the dates of site occupation and confirm the construction sequence of several houses determined originally via stratigraphic and archaeological evidence. We were able to graphically and statistically crossmatch 13 measurement series representing 10 posts from 5 of the 6 structures, yielding a 157-year floating chronology (average interseries correlation = 0.60). We were unable to absolutely crossdate this floating chronology with the only regional reference chronology long enough (back to 1378 CE) to reach the 16th century, an eastern red cedar chronology from eastern Tennessee. Archaeological evidence indicated Houses 8 and 23.4 were built later in the King site occupancy, confirmed by the tree-ring dates as both houses have the youngest tree rings of the five structures. House 14 had the oldest outermost tree rings but archaeological evidence suggests this house also was likely constructed late in the King site occupancy. We propose some posts were salvaged and reused from abandoned houses as the King site became rapidly depopulated in the last 10–20 years of site occupancy, thus explaining the age of posts used in House 14. We urge archaeologists working in the Southeastern U.S. to consider developing a more formal process for exhuming and preserving charcoalized wood remains from archaeological sites so that these samples can be evaluated using dendrochronological techniques. 相似文献
8.
Igor Drobyshev P. Charles Goebel Yves Bergeron R. Gregory Corace 《Dendrochronologia》2012,30(2):137-145
The study of forests dominated by red pine (Pinus resinosa Ait.), one of the few fire-resistant tree species of eastern North America, provides an opportunity to reconstruct long-term fire histories and examine the temporal dynamics of climate forcing upon forest fire regimes. We used a 300-year long spatially explicit dendrochronological reconstruction of the fire regime for Seney National Wildlife Refuge (SNWR, 38,531 ha), eastern Upper Michigan to: (1) identify fire size thresholds with strong vs. weak climate controls, (2) evaluate effect of landform type (outwash channel vs. sand ridges) in modifying climate–fire associations, and (3) check for the presence of temporal changes in the climate control of large fire events over the time period 1700–1983. We used a summer drought sensitive red pine chronology (ITRDB code can037) as a proxy of past fire-related climate variability. Results indicated that fires >60 ha in sand-ridge-dominated portions of SNWR and >100 ha in outwash channels were likely climatically driven events. Climate–fire associations varied over time with significant climate–fire linkages observed for the periods 1700–1800 (pre-EuroAmerican), 1800–1900 (EuroAmerican settlement) and 1900–1983 (modern era). Although an increase in fire activity at the turn of 20th century is commonly associated with human sources of ignitions, our results suggest that such an increase was also likely a climatically driven episode. 相似文献
9.
《Basic and Applied Ecology》2014,15(6):516-523
The reduction of insect herbivory is one of the services provided by tree diversity in forest ecosystems. While it is increasingly acknowledged that the compositional characteristics of tree species assemblages play a major role in triggering associational resistance to herbivores, underlying mechanisms are less well known. We addressed this question in the ORPHEE experiment by assessing pine processionary moth infestations (Thaumetopoea pityocampa) across a tree diversity gradient from pine monocultures to five species mixtures. We showed that tree species richness per se had no effect on the probability of attack by this pest. By contrast, the infestation rate was strongly dependent on plot composition. Mixtures of pines (Pinus pinaster) and birches (Betula pendula) were less prone to T. pityocampa infestations, whereas mixtures of pines and oaks (Quercus spp.) were more often attacked than pine monocultures. By taking into account the relative height of pines and associated broadleaved species, this effect could be explained by pine apparency. Pines were on average 343 ± 5 cm height. Birches, as fast growing trees, were slightly taller than pines (363 ± 6 cm), while oak trees were significantly smaller (74 ± 1 cm). Host trees of T. pityocampa were then partly hidden in mixtures of pines and birches but more apparent in mixtures with oaks. We suggest that reduced pine apparency disrupted visual cues used by female moths to select host trees prior to oviposition. This study highlights the need to take into account tree traits such as growth rate when selecting the tree species that have to be associated in order to improve forest resistance to pest insects. 相似文献
10.
According to the green wave hypothesis, herbivores follow the flush of spring growth of forage plants during their spring migration to northern breeding grounds. In this study we compared two green wave indices for predicting the timing of the spring migration of avian herbivores: the satellite-derived green wave index (GWI), and an index of the rate of acceleration in temperature (GDDjerk). The GWI was calculated from MODIS normalized difference vegetation index (NDVI) satellite imagery and GDDjerk from gridded temperature data using products from the global land data assimilation system (GLDAS). To predict the timing of arrival at stopover and breeding sites, we used four years (2008–2011) of tracking data from 12 GPS-tagged barnacle geese, a long-distance herbivorous migrant, wintering in the Netherlands, breeding in the Russian Arctic. The stopover and breeding sites for these birds were identified and the relations between date of arrival with the date of 50% GWI and date of peak GDDjerk at each site were analyzed using mixed effect linear regression. A cross-validation method was used to compare the predictive accuracy of the GWI and GDDjerk indices. Significant relationships were found between the arrival dates at the stopover and breeding sites for the dates of 50% GWI as well as the peak GDDjerk (p < 0.01). The goose arrival dates at both stopover and breeding sites were predicted more accurately using GWI (R2cv = 0.68, RMSDcv = 5.9 and R2cv= 0.71, RMSDcv = 3.9 for stopover and breeding sites, respectively) than GDDjerk. The GDDjerk returned a lower accuracy for prediction of goose arrival dates at stopover ( R2cv = 0.45, RMSDcv = 7.79) and breeding sites (R2cv = 0.55, RMSDcv = 4.93). The positive correlation between the absolute residual values of the GDDjerk model and distance to the breeding sites showed that this index is highly sensitive to latitude. This study demonstrates that the satellite-derived green wave index (GWI) can accurately predict the timing of goose migration, irrespective of latitude and therefore is suggested as a reliable green wave index for predicting the timing of avian herbivores spring migration. 相似文献
11.
This study investigates Pb isotope ratios at low concentrations (parts per billion; ppb) in tree rings and soils in the Northern Athabasca Oil Sands Region (NAOSR), western Canada, to evaluate if: (1) climatic conditions influence on tree-ring Pb assimilation; and (2) such low Pb content allows inferring the regional Pb depositional history.Our results reflect the influence of winter snow cover and the importance of minimum temperature and precipitation in spring and summer on the bioavailability of Pb and its passive assimilation by trees in sub-arctic semi-humid climatic conditions. Winter conditions can influence the state of root systems that subsequently impacts the following growth period, while spring and summer conditions likely control microbial processes and water source, and may thus impact Pb assimilation by trees. Thus, the results of tree-ring Pb concentrations show interesting correlation with cumulated snow from November of the previous year to February (ρ = 0.53; P < 0.01; n = 36). Likewise, the 206Pb/207Pb ratios inversely correlate with minimum temperature from April to September (ρ = −0.67; P < 0.01; n = 40) and precipitation from May to August (ρ = −0.42; P < 0.01; n = 36). The isotopic results also suggest that the effects of climatic variations are superimposed by regional industrial Pb deposition: Western North American Aerosols (WNAA) and fugitive dust from the oil sands mining operations appear to be the most likely sources.Importantly, this study suggests that even at low Pb concentrations, tree-ring Pb isotopes are modulated by climatic conditions and potential input of regional and long-range transport of airborne Pb. These interpretations open the possibility of using Pb isotopes as an environmental tool for inferring the pollution history in remote regions, and improving our understanding of its natural cycle through the forest environment. 相似文献
12.
Following the successful utilisation of lake preserved sub-fossil woody material to extend living Scots pine chronologies in Scandinavia, ongoing research in the Scottish Highlands aims to build a similar multi-millennial long climatically sensitive pine chronology. This paper details explorative research testing the use of sonar methods to facilitate the search for sub-fossil material in lake environments. Although the method clearly identifies elongate anomalies that are consistent with submerged tree stems in water depths >1.5 m, it does not allow the identification of sub-fossil wood remnants in shallow water (<1.0 m) or heavily vegetated bays. Therefore, for the successful survey of lakes, a combination of traditional and sonar methods must be applied. Ongoing research will now explore the utilisation of these methods to more remote locations where boat access is not possible. 相似文献
13.
Few Southern Hemisphere tree-ring chronologies exceed 1000 years in length. We present a ca. 1700 years of indexed values for the long-lived conifer Athrotaxis selaginoides at Cradle Mt in southeastern Australia and compare it with the only other published millennial-plus length tree-ring chronology for Australia: the nearby Mt Read Lagarostrobos franklinii. We use simple correlation function and pointer year analyses to compare the climate responses of the two species (temperature, precipitation and growing degree days). Both chronologies show accelerated growth at their modern ends, but this growth acceleration is not synchronous, beginning approximately a quarter of a century earlier at the Cradle Mt site. This discrepancy may highlight the relevance of chronology composition and/or physiological differences in the species. Although the seasonality of the climatic responses of the two species is similar, that of A. selaginoides is generally weaker than that of L. franklinii. Somewhat paradoxically, the only pointer years in common between the chronologies are 1898 and 1908 CE. The periods from 600 to 900 CE and ∼1200–1450 CE are conspicuous for their absence of positive pointer years while no negative pointer years occur for either site from ∼1200–1350 CE. It is possible that differing patterns of pointer years can be partially explained by a peak in establishment from ∼1150–1850 CE at the Mt Read L. franklinii site compared to continuous establishment at Cradle Mt. Although statistically significant and time-stable climate responses for the A. selaginoides chronology are too weak to base a single-chronology climate reconstruction on, the long chronology will likely make an important contribution to future multi-proxy temperature reconstructions for southeastern Australia. 相似文献
14.
Mingxing Cui Xingyuan He Nicole Davi Zhenju Chen Xianliang Zhang Junjie Peng Wei Chen 《Dendrochronologia》2013,31(1):1-8
In order to detect the response of trees to environmental pollution in Shenyang during the last century, tree rings of two 100+ year old Chinese pine (Pinus tabulaeformis Carr.) were analyzed for nine trace element concentrations (K, Ca, Mg, Mn, Cu, Zn, Al, Pb and Cd) and compared to local environmental change. The concentrations of Cu, Zn and Al had significant (p < 0.01) increasing trends after 1940s and correlated significantly (p < 0.01), with increasing production of nonferrous metal from local industrial processing. Concentrations of nutrient element (K, Ca and Mg) showed significant (p < 0.01) increasing trend from heartwood to sapwood with declines in the last three decades. Significant correlation between climatic factors and element concentration in tree rings were also found, in which the temperature (November to May) and relative humidity in April and May showed significant positive correlation with Ca, Zn and Cu (p < 0.05) as well as Al (p < 0.01) concentrations in tree rings. April rainfall showed significant positive correlation with K and Zn (p < 0.05) as well as Al (p < 0.01) concentration in tree rings. The results suggest that tree rings from Chinese pine in Shenyang are sensitive to environmental change and have the potential to be used as a biomonitor for the environmental pollution. The results also demonstrate the feasibility of applying dendrochemical techniques to areas with limited samples. 相似文献
15.
《Environmental and Experimental Botany》2007,59(3):354-360
Despite the fact that genome size should be constant at species level, many reports of intraspecific variations exist. Thus, we carried out an analysis to determine the possible existence of nuclear DNA content variation in European black pine (Pinus nigra s.l.), a good model for such a study given its karyological uniformity, morphological polymorphism, broad geographical distribution, ecological plasticity and taxonomic heterogeneity. The panel comprised 20 populations across the natural range of P. nigra from Europe, Northwest Africa and Asia Minor including five subspecies: subsp. nigra, salzmanni, dalmatica, pallasiana and mauretanica. Mean 1C DNA content of the species was 23.62 pg (±0.209) assessed by flow cytometry. This converts to 23.1 G base pairs. The coefficients of variation within and between populations did not exceed 2.6%. Although we had already reported the existence of significant differences for three Black pine populations in our previous work on five Pinus spp. [Bogunic, F., Muratovic, E., Brown, S.C., Siljak-Yakovlev, S., 2003. Genome size of five Pinus from Balkan region. Plant Cell Rep. 22, 59–63], intraspecific variation was not confirmed in the present study dealing with many more populations. Subspecific divisions of Black pine were characterised with following mean values: subsp. pallasiana—23.80 pg, dalmatica—23.79 pg, nigra—23.65 pg, salzmanni—23.55 pg, and mauretanica—23.24 pg. A positive relationship between genome size and longitude was observed (r = 0.44, p < 0.05). We conclude that the diversification of populations of P. nigra has occurred without significant genome size changes throughout its wide geographical range from ecologically contrasting habitats. A clinal mode of genome size variation is present, in line with hypothesis of P. nigra spreading from south-western Asia towards European habitats. 相似文献
16.
《Ecological Engineering》2007,29(2):192-199
Trees integrated into the range- and pasturelands of Florida could remove nutrients from deeper soil profiles that would otherwise be transported to water bodies and cause pollution. Soil nitrogen (N) and phosphorus (P) concentrations were monitored in three pastures: a treeless pasture of bahiagrass (Paspalum notatum); a pasture of bahiagrass under 20-year-old slash pine (Pinus elliotti) trees (silvopasture); and a pasture of native vegetation under pine trees (native silvopasture). Soil analysis from 10 profiles within each pasture showed that P concentrations were higher in treeless pasture (mean: 9.11 mg kg−1 in the surface to 0.23 mg kg−1 at 1.0 m depth) compared to silvopastures (mean: 2.51 and 0.087 mg kg−1, respectively), and ammonium–N and nitrate–N concentrations were higher in the surface horizon of treeless pasture. The more extensive rooting zones of the combined stand of tree + forage may have caused higher nutrient uptake from silvopastures than treeless system. Further, compared to treeless system, soils under silvopasture showed higher P storage capacity. The results suggest that, compared to treeless pasture, silvopastoral association enhances nutrient retention in the system and thus reduces chances for nutrient transport to surface water. The study reflects the scope for applying ecological-engineering and ecosystem-restoration principles to silvopastoral-system design. 相似文献
17.
Tatjana Kuznetsova Katrin Rosenvald Ivika Ostonen Heljä-Sisko Helmisaari Malle Mandre Krista Lõhmus 《Ecological Engineering》2010,36(4):495-502
Early survival and growth of black alder, silver birch and Scots pine were investigated on reclaimed extremely stony and heterogeneous calcareous (pH 8) opencast oil shale mining areas (OOSMAs). Biomass allocation, production, leaf and root adaptations, and mineral nutrition in relation to tree species and soil heterogeneity were analysed. The adaptive strategies of tree species in first-year plantations on OOSMA were different. Scots pine allocated 1.5–2 times more biomass into leaves and fine roots than deciduous trees. The lower leaf/fine root biomass ratio was in proportion to the better survival (%) of seedlings, decreasing in the following order: black alder (93%) ≥ Scots pine (83%) > silver birch (64%). Deciduous trees improved mineral nutrition more by fine-root morphological adaptations than Scots pine; e.g. the mean specific root length (SRL, m g?1) of short roots increased in the following order: Scots pine (62) < black alder (172) < silver birch (314). The effect of soil heterogeneity on growth and adaptations was minor. All studied species suffered from P and N, and deciduous species also from K deficiency. In the first year after planting, black alder was best adapted to the harsh conditions of the post-mining substrate. The approaches of this study can be used for other regions where wastelands require reclamation. 相似文献
18.
《Lichenologist (London, England)》2001,33(3):215-229
Abstract:Epiphytic lichens (and some non-lichenized fungi) on 34 coppices (204 stems) ofCorylus avellana were investigated in a 140 ha study area in south-western Norway. A total of 65 species were recorded on a total bark area of 63 m2. Corylus in broad-leaved deciduous forest supported more species of macrolichens, and fewer species of microlichens, than Corylus in pine forest. The macrolichen flora of the deciduous forest differed from that of the pine forest by having a rich flora of species belonging to the Lobarion alliance. OldCorylus coppices with tall stems (>8 m), large girth (>8 cm diameter at breast height) and a noticeable cover of macrolichens (>10% of bark area) supported the highest number of rare species, and overall, species of macrolichens. More than 50% cover of microlichens indicated richness and rarity of microlichens on Corylus. 相似文献
19.
《L'Anthropologie》2021,125(5):102968
Palaeolithic archaeology in Tohoku region has long been discussed on constructing chronology, however it is difficult to build reliable chronological order because of poor stratigraphic excavations. In recent radiocarbon dating has advanced. In this paper I discuss the relation between chronology and radiocarbon dating in Tohoku region. At first, I categorize the Palaeolithic industries and establish the chronology by analyzing tool typology, lithic technology, and stratigraphic data. I correlate it with radiocarbon data from sites in Tohoku region. The result of analysis shows that Upper Palaeolithic industries are divided into 18 categories and 8 periods on chronology. The calibration curve IntCal 13 indicated that oldest Early Upper Palaeolithic site appeared around 37,000 cal BP, and late Upper Palaeolithic started about 27,000 cal BP. The pottery first appeared as far back as around 16,000 cal BP. Now we do not have enough radiocarbon data, so we have to gather and examine more 14C data. 相似文献
20.
《Peptides》2013
During gestation there are important changes in maternal metabolism and an increase in insulin resistance, coinciding with an increase in adiposity. Chemerin is an adipocytokine which is expressed and secreted in various tissues, including placenta, and may play an important role in metabolic regulation during pregnancy. The aim of this study was to determine serum levels of chemerin during gestation and compare them to other indicators of insulin resistance. A cross-sectional study was carried out analyzing serum chemerin levels of 20 pregnant women during three gestational periods, early, middle, and late (between the 10th and 14th, the 23rd and 26th, and the 34th and 37th week) and 20 non-pregnant women were used as a control group. An analysis of chemerin levels during the menstrual cycle was performed in an eumenorrheic group (n = 16) in the early follicular (cycle day 4 ± 1) and the midluteal phase (cycle day 22 ± 1), demonstrating that serum chemerin levels did not fluctuate significantly. Serum levels of chemerin were significantly elevated during late gestation when compared to early (P < 0.001) and middle (P = 0.001) gestation and a negative correlation between serum chemerin and adiponectin levels (r = −0.1643) became more significant when the non-pregnant group was included in the calculations (r = −0.2471). There was no significant association of triglycerides, total cholesterol, LDL, HDL, insulin, and HOMA levels with chemerin. Although chemerin rose significantly and is negatively associated with adiponectin levels, it is not correlated with other markers of insulin sensitivity, suggesting that more study is needed to determine whether chemerin is useful in predicting insulin resistance during gestation. 相似文献