A comparison of two tree-ring-index standardization techniques

1992 ◽  
Vol 22 (12) ◽  
pp. 1922-1928 ◽  
Author(s):  
J.O. Murphy ◽  
J.G. Palmer
Keyword(s):  
Tree Ring ◽  
Low Frequency ◽  
Polynomial Functions ◽  
Spectral Profile ◽  
Biological Growth ◽  
Climatic Variations ◽  
Highly Correlated ◽  
Index Standardization ◽  
Statistical Indicators ◽  
Mean Sensitivity

A comparison is made between two tree-ring index chronologies that are based on the same set of site ring measurements but use two different standardization techniques. Both polynomial functions and 50-year Gaussian filtering procedures have been employed to represent the biological growth curve, thereby essentially detrending the resulting ring-index chronologies. It is established that although both approaches generate highly correlated time series at lag 0, significant differences exist in the autocorrelation functions, mean sensitivity values, and spectral amplitudes at the low frequency end of the spectrum. The exclusion of these periodicities is of concern, as they are normally associated with longer term climatic variations as well as site influences. Consequently, the nature of the descriptive statistical indicators generally considered, especially the spectral profile, should be established in conjunction with possible standardization options. Also, it would be prudent to appraise existing chronologies, on the same basis, prior to undertaking any dendrochronological applications.

Tree-ring variables as proxy-climate indicators: Problems with low-frequency signals

1996 ◽  
pp. 9-41 ◽  
Author(s):  
Keith R Briffa ◽  
Philip D Jones ◽  
Fritz H Schweingruber ◽  
Wibjörn Karlén ◽  
Stepan G Shiyatov
Keyword(s):  
Tree Ring ◽  
Low Frequency ◽  
Climate Indicators

scholarly journals Comparing selected fire regime condition class (FRCC) and LANDFIRE vegetation model results with tree-ring data

2010 ◽  
Vol 19 (1) ◽  
pp. 1 ◽  
Author(s):  
Tyson L. Swetnam ◽  
Peter M. Brown
Keyword(s):  
Tree Ring ◽  
Ponderosa Pine ◽  
Fire Regime ◽  
Reference Conditions ◽  
Low Frequency ◽  
Fire Regimes ◽  
Vegetation Types ◽  
Tree Ring Data ◽  
Map Data ◽  
Fire Regime Condition Class

Fire Regime Condition Class (FRCC) has been developed as a nationally consistent interagency method in the US to assess degree of departure between historical and current fire regimes and vegetation structural conditions across differing vegetation types. Historical and existing vegetation map data also are being developed for the nationwide LANDFIRE project to aid in FRCC assessments. Here, we compare selected FRCC and LANDFIRE vegetation characteristics derived from simulation modeling with similar characteristics reconstructed from tree-ring data collected from 11 forested sites in Utah. Reconstructed reference conditions based on trees present in 1880 compared with reference conditions modeled by the Vegetation Dynamics Development Tool for individual Biophysical Settings (BpS) used in FRCC and LANDFIRE assessments showed significance relationships for ponderosa pine, aspen, and mixed-conifer BpS but not for spruce–fir, piñon–juniper, or lodgepole pine BpS. LANDFIRE map data were found to be ~58% accurate for BpS and ~60% accurate for existing vegetation types. Results suggest that limited sampling of age-to-size relationships by different species may be needed to help refine reference condition definitions used in FRCC assessments, and that more empirical data are needed to better parameterize FRCC vegetation models in especially low-frequency fire types.

scholarly journals Low-frequency noise inδ13C andδ18O tree ring data: A case study ofPinus uncinatain the Spanish Pyrenees

2010 ◽  
Vol 24 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Jan Esper ◽  
David C. Frank ◽  
Giovanna Battipaglia ◽  
Ulf Büntgen ◽  
Christopher Holert ◽  
...  
Keyword(s):  
Tree Ring ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Tree Ring Data ◽  
Spanish Pyrenees

Low-frequency divergence of tree-ring d18O variations on both sides of climatic boundary mountain of eastern China since 1980s

2020 ◽  
Author(s):  
Qiang Li ◽  
Yu Liu ◽  
Huiming Song
Keyword(s):  
Relative Humidity ◽  
Tree Ring ◽  
Time Scale ◽  
Eastern China ◽  
Sampling Site ◽  
Low Frequency ◽  
Mountain Range ◽  
Decadal Time Scale ◽  
Qinling Mountain ◽  
Significant Divergence

<p>The Qinling Mountain is the most important mountain range in eastern China, and is the geographical boundary and the climatic boundary. We investigated tree-ring d18O variations in South and North Slope of the Qinling Mountain, and found that the variations of tree-ring  d18O were significantly correlated over the past two and a half centuries (r=0.641, n=247, p<0.001). And they are negatively correlated with relative humidity and precipitation, and positively correlated with temperature. Compared with the various hydroclimate-related time series in the surrounding area, it is found that both can represent the region's long-term hydroclimate change. The consistent changes in the interannual time scale may be due to the common modulation of ENSO. However, on the decadal time scale, there have been significant divergence between the two tree-ring  d18O series since 1981 and the divergence may be caused by changes in relative humidity at the sampling site, suggesting that in the context of global warming, although the warming range is the same, but the triggered relative humidity changes are not consistent. In addition, changes in PDO may be another cause of low-frequency difference.</p>

scholarly journals Wavelet analysis of low-frequency variability in oak tree-ring chronologies from east Central Europe

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
Asok K. Sen ◽  
Zoltán Kern
Keyword(s):  
Time Series ◽  
Wavelet Analysis ◽  
Central Europe ◽  
Tree Ring ◽  
Low Frequency ◽  
Wavelet Coherence ◽  
Time Interval ◽  
East Central Europe ◽  
East Central ◽  
Oak Tree

AbstractThis study investigates the low-frequency (interannual and longer period) variability in three hydroclimatic records from east Central Europe. Two of these records consist of climate proxies derived from oak-tree rings in Bakta forest, and Balaton Highlands in Hungary, for the time interval 1783-2003. The third record consists of homogenized instrumental precipitation data from Budapest, Hungary, from 1842 to 2003. Using wavelet analysis, the three time series are analyzed and compared with one another. It is found that all three time series exhibit strong interannual variability at the 2-4 years timescales, and these variations occur intermittently throughout the length of each record. Significant variability is also observed in all the records at decadal timescales, but these variations persist for only two to three cycles. Wavelet coherence among the various time series is used to explore their time-varying correlation. The results reveal significant coherence at the 2-4 years band. At these timescales, the climatic variations are correlated to the tree-ring signal over different time intervals with changing phase. Increased (decreased) contribution of large-scale stratiform precipitation offers a potential explanation for enhanced (faded) coherence at the interannual timescale. Strong coherence was also observed occasionally at decadal timescales, however these coherences did not appear uniformly. These results reinforce the earlier assertion that neither the strength nor the rank of the similarity of the local hydroclimate signals is stable throughout the past two centuries.

A COMPARISON OF TREE-RING FEATURES IN PICEA ABIES AS CORRELATED WITH CLIMATE

IAWA Journal ◽  
2000 ◽  
Vol 21 (4) ◽  
pp. 403-416 ◽  
Author(s):  
Rupert Wimmer ◽  
Michael Grabner
Keyword(s):  
Picea Abies ◽  
Tree Ring ◽  
Ring Width ◽  
Climatic Conditions ◽  
Climatic Data ◽  
Indirect Measure ◽  
Resin Duct ◽  
Temperature And Precipitation ◽  
Latewood Density ◽  
Highly Correlated

This paper presents an analysis of 16 anatomical variables measured on 20 spruce trees [Picea abies (L.) Karst.] from sites in the managed forest district Seyde, Eastern Ore Mountains, south of Dresden, Germany. Ring width and latewood proportion did not show significant relationships with monthly climatic data, whereas maximum density, latewood cell-wall proportion and latewood density were highly correlated with temperature and precipitation. The climatic signals expressed in resin duct density, ray height, tracheid length and microfibril angles were less pronounced. Of 16 tree-ring parameters, densitometry – as an indirect measure of xylem anatomy – has again shown its great potential to record climatic conditions.

Regression Model for the 22-year Hale Solar Cycle Derived from High Altitude Tree-ring Data

1994 ◽  
Vol 11 (2) ◽  
pp. 157-163 ◽  
Author(s):  
J. O. Murphy ◽  
H. Sampson ◽  
T. T. Veblen ◽  
R. Villalba
Keyword(s):  
Solar Cycle ◽  
Regression Model ◽  
High Altitude ◽  
Tree Ring ◽  
Magnetic Cycle ◽  
Tree Ring Data ◽  
Highly Correlated ◽  
Successive Maximum ◽  
Index Time Series ◽  
Past 300 Years

AbstractInitially some simple analytical properties based on the annual Zürich relative sunspot number are established for the 22-year Hale solar magnetic cycle. Since about AD1850, successive maximum sunspot numbers in a Hale cycle are highly correlated. Also, a regression model for the reconstruction of the 22-year Hale cycle has been formulated from proxy tree-ring data, obtained from spruce trees growing at a high altitude site in White River National Forest in Colorado. Over a considerable fraction of the past 300 years to AD1986, the ring-index time series power spectrum exhibits a strong 22-year periodicity, and more recently a significant spectral peak (at the 95% confidence level) at approximately 11 years. The model shows that the greatest variation in ‘amplitude’ in the magnetic cycle occurs over the early decades of the eighteenth century, when the sample size is small. Thereafter, a nearly constant amplitude is maintained until about AD1880 when a break occurs in both phase correspondence and amplitude, extending over the next three cycles. From AD1950 the signal recovers phase with the solar cycle, with reduced but increasing amplitude.

A fistful of shells: amplifying sclerochronological and palaeoclimate signals from molluscan death assemblages

2009 ◽  
Vol 146 (6) ◽  
pp. 917-930 ◽  
Author(s):  
S. HELAMA ◽  
J. K. NIELSEN ◽  
M. MACIAS FAURIA ◽  
I. VALOVIRTA
Keyword(s):  
Sample Size ◽  
Tree Ring ◽  
Small Sample Size ◽  
Low Frequency ◽  
Small Sample ◽  
Pearl Mussel ◽  
Climate Signal ◽  
Growth Variability ◽  
Low Frequency Variability ◽  
The Individual

AbstractA growing body of literature is using sclerochronological information to infer past climates. Sclerochronologies are based on series of skeletal growth records of molluscs that have been correctly aligned in time. Incremental series are obtained from a number of shells to assess the temporal control and improve the climate signal in the final chronology. Much of the sclerochronological theory has been adopted from tree-ring science, due to the longer tradition and more firmly established concepts of chronology construction in dendrochronology. Compared to tree-ring studies, however, sclerochronological datasets are often characterized by relatively small sample size. Here we evaluate how effectively palaeoclimatic signal can be extracted from such a suite of samples. In so doing, the influences of the very basic methods that are applied in nearly every sclerochronological study to remove the non-climatic growth variability prior to palaeoclimatic interpretations, are ranked by their capability to amplify the desired signal. The study is performed in the context of six shells that constitute a bicentennial growth record from annual shell increments of freshwater pearl mussel. It was shown that when the individual series were detrended using the models set by the mean or the median summary curves for ageing (that is, applying Regional Curve Standardization, RCS), instead of fitting the ageing mode statistically to each series, the resulting sclerochronology displayed more low-frequency variability. Consistently, the added low-frequency variability evoked higher proxy–climate correlations. These results show the particular benefit of using the RCS method to develop sclerochronologies and preserve their low-frequency variations. Moreover, calculating the ageing curve and the final chronology by median, instead of mean, resulted in an amplified low-frequency climate signal. The results help to answer a growing need to better understand the behaviour of the sclerochronological data. In addition, we discuss the pitfalls that may potentially disrupt palaeoclimate signal detection in similar sclerochronological studies. Pitfalls may arise from shell taphonomy, water chemistry, time-variant characters of biological growth trends and small sample size.

scholarly journals Composition and Distribution of Pythium Communities in Wheat Fields in Eastern Washington State

2003 ◽  
Vol 93 (7) ◽  
pp. 867-873 ◽  
Author(s):  
T. C. Paulitz ◽  
K. Adams
Keyword(s):  
Soil Type ◽  
Low Frequency ◽  
Hierarchical Cluster ◽  
Annual Precipitation ◽  
Frequency Distributions ◽  
Higher Temperature ◽  
Highly Correlated ◽  
Eastern Washington ◽  
The Relationship ◽  
Average Annual Precipitation

Pythium spp. were isolated from a mixture of soil and roots collected from 80 wheat fields in eastern Washington in the summer of 2000 from an area encompassing approximately 27,000 km2. These sites covered a range of soil textures (coarse to fine, silty loess), average annual precipitation (200 to 600 mm), and average annual temperatures (7 to 11°C). Soil type and annual precipitation run in an east-west gradient, while temperature has a north-south gradient. Species were identified using classical methods and by sequencing the internal transcribed spacer (ITS)-1 region of the rDNA and comparing these sequences to a database from a worldwide collection of Pythium spp. The species with the highest frequency of occurrence among all the sites were P. abappressorium sp. nov. (A) (50%), P. rostratum (R) (40%), P. debaryanum (D) (37.5%), P. heterothallicum (H) (33.7%), P.oligandrum (O) (31.2%), an unidentified P. sp. (aff. echinulatum) (E) (25%), and P. ultimum (U) (18%). P. intermedium, P. irregulare, P. paroecandrum, P. sylvaticum, P. dissimile, and P. dissoticum were isolated at a low frequency. From one to six species were isolated at each site, and there were 46 different species combinations detected. The species presence/absence data from all sites were analyzed with Jaccard's similarity coefficient hierarchical cluster analysis. Six communities were identified (species within each community designation in order of frequency among the sites within the community)-AD, AOU, AR, DEH, HE, and RU. In general, P. abappressorium was evenly distributed over all zones. AOU was more prevalent in zones with lower precipitation and coarser soil, while DEH and HE were associated with zones with higher precipitation and finer-textured soils on the basis of comparison of frequency distributions with the expected distribution over all the sites. The RU community was more prevalent in higher temperature zones. Canonical correspondence analysis was performed to examine the relationship between species and environmental variables. Soil type and precipitation were highly correlated with each other and with axis 1, which separated P. ultimum and P. abappressorium (lower variable values) from P. heterothallicum (higher variable values). Axis 2 and 3 were most correlated with temperature, and these axes separated P. oligandrum (higher value) from P. debaryanum (lower value) and P. ultimum-P. rostratum from the other species. The results suggest that Pythium species composition, distributions, and associations on a given crop may be influenced by environmental factors at a mesoscale level (100 to 1,000,000 ha).

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