Two hundred year variation of southern red spruce radial growth as estimated by spectral analysis

1993 ◽  
Vol 23 (2) ◽  
pp. 291-301 ◽  
Author(s):  
Gregory A. Reams ◽  
N.S. Nicholas ◽  
S.M. Zedaker
Keyword(s):  
North Carolina ◽  
Spectral Analysis ◽  
Radial Growth ◽  
Low Frequency ◽  
Local Maximum ◽  
High Elevation ◽  
Red Spruce ◽  
Tree Ring Data ◽  
Sine And Cosine Functions ◽  
Cosine Functions

Spectral analysis was applied to high-elevation (≥1800 m) old-growth (≥200 years) red spruce (Picearubens Sarg.) tree-ring data from eight plots on Clingmans Dome, North Carolina. Low-frequency sine and cosine functions with wavelengths greater than or equal to 10 years accounted for between 76 and 90% of the variation in mean ring widths for all eight sites analyzed. Mean radial growth has increased and decreased no less than nine times over the last 200 years, with no evidence of constant radial growth for extended periods of time. Since the mid-1960s, radial growth has decreased and increased twice and is currently increasing through 1986, the last year of sampling. Growth in 1976 was equal to or greater than pre-1965 levels. A local maximum (mid-1960s) of the periodic cycles in radial growth coincides with the reported downturn in radial growth of red spruce at other locations in the southern Appalachians. Verification of historical growth periodicities can best be evaluated through continual monitoring of trees from a greater number of sites.

Synchronie large-scale disturbances and red spruce growth decline

1993 ◽  
Vol 23 (7) ◽  
pp. 1361-1374 ◽  
Author(s):  
Gregory A. Reams ◽  
Paul C. Van Deusen
Keyword(s):  
Tree Ring ◽  
Radial Growth ◽  
Large Scale ◽  
Red Spruce ◽  
Southern Appalachians ◽  
Time Interval ◽  
Growth Reduction ◽  
Usda Forest Service ◽  
Tree Ring Data ◽  
Growth Decline

Tree-ring data from the USDA Forest Service Forest Inventory & Analysis and other independent sources were used to study coincidence of changes in growth and large-scale disturbances. Numerous studies report that mean radial growth of red spruce (Picearubens Sarg.) declined synchronously throughout its range in the early 1960s. We use red spruce tree-ring data from most of the major studies to show that the synchronicity of red spruce growth decline is likely the outcome of the large-scale disturbances that occurred throughout the northeastern red spruce ecosystem in the late 1930s to early 1950s. Large-scale disturbances are either not detectable or not present in the same time interval in the southern Appalachians. This appears to correspond to an absence of a 1960s radial growth reduction in this region.

Recent growth of conifer species of western North America: assessing spatial patterns of radial growth trends

2001 ◽  
Vol 31 (3) ◽  
pp. 526-538 ◽  
Author(s):  
Donald McKenzie ◽  
Amy E Hessl ◽  
David L Peterson
Keyword(s):  
Spatial Patterns ◽  
High Latitude ◽  
Low Frequency ◽  
High Elevation ◽  
Growth Patterns ◽  
Conifer Species ◽  
Growth Trend ◽  
Growth Trends ◽  
Low Frequency Variability ◽  
Tree Ring Data

We explored spatial patterns of low-frequency variability in radial tree growth among western North American conifer species and identified predictors of the variability in these patterns. Using 185 sites from the International Tree-Ring Data Bank, each of which contained 10–60 raw ring-width series, we rebuilt two chronologies for each site, using two conservative methods designed to retain any low-frequency variability associated with recent environmental change. We used factor analysis to identify regional low-frequency patterns in site chronologies and estimated the slope of the growth trend since 1850 at each site from a combination of linear regression and time-series techniques. This slope was the response variable in a regression-tree model to predict the effects of environmental gradients and species-level differences on growth trends. Growth patterns at 27 sites from the American Southwest were consistent with quasi-periodic patterns of drought. Either 12 or 32 of the 185 sites demonstrated patterns of increasing growth between 1850 and 1980 A.D., depending on the standardization technique used. Pronounced growth increases were associated with high-elevation sites (above 3000 m) and high-latitude sites in maritime climates. Future research focused on these high-elevation and high-latitude sites should address the precise mechanisms responsible for increased 20th century growth.

Two hundred year variation of southern red spruce radial growth as estimated by spectral analysis: Comment

1994 ◽  
Vol 24 (11) ◽  
pp. 2299-2304 ◽  
Author(s):  
S.B. McLaughlin ◽  
T.J. Blasing ◽  
D.J. Downing
Keyword(s):  
Spectral Analysis ◽  
Radial Growth ◽  
Red Spruce

not available

scholarly journals Influence of sampling and disturbance history on climatic sensitivity of temperature-limited conifers

The Holocene ◽  
2018 ◽  
Vol 28 (10) ◽  
pp. 1574-1587 ◽  
Author(s):  
Miloš Rydval ◽  
Daniel L Druckenbrod ◽  
Miroslav Svoboda ◽  
Volodymyr Trotsiuk ◽  
Pavel Janda ◽  
...  
Keyword(s):  
Tree Ring ◽  
Ring Width ◽  
Low Frequency ◽  
High Elevation ◽  
Climate Signal ◽  
High Frequency Response ◽  
Climatic Trends ◽  
Tree Ring Data ◽  
Temperature Signal ◽  
Romanian Carpathians

Accurately capturing medium- to low-frequency trends in tree-ring data is vital to assessing climatic response and developing robust reconstructions of past climate. Non-climatic disturbance can affect growth trends in tree-ring-width (RW) series and bias climate information obtained from such records. It is important to develop suitable strategies to ensure the development of chronologies that minimize these medium- to low-frequency biases. By performing high density sampling (760 trees) over a ~40-ha natural high-elevation Norway spruce ( Picea abies) stand in the Romanian Carpathians, this study assessed the suitability of several sampling strategies for developing chronologies with an optimal climate signal for dendroclimatic purposes. There was a roughly equal probability for chronologies (40 samples each) to express a reasonable ( r = 0.3–0.5) to non-existent climate signal. While showing a strong high-frequency response, older/larger trees expressed the weakest overall temperature signal. Although random sampling yielded the most consistent climate signal in all sub-chronologies, the outcome was still sub-optimal. Alternative strategies to optimize the climate signal, including very high replication and principal components analysis, were also unable to minimize this disturbance bias and produce chronologies adequately representing climatic trends, indicating that larger scale disturbances can produce synchronous pervasive disturbance trends that affect a large part of a sampled population. The Curve Intervention Detection (CID) method, used to identify and reduce the influence of disturbance trends in the RW chronologies, considerably improved climate signal representation (from r = 0.28 before correction to r = 0.41 after correction for the full 760 sample chronology over 1909–2009) and represents a potentially important new approach for assessing disturbance impacts on RW chronologies. Blue intensity (BI) also shows promise as a climatically more sensitive variable which, unlike RW, does not appear significantly affected by disturbance. We recommend that studies utilizing RW chronologies to investigate medium- to long-term climatic trends also assess disturbance impact on those series.

Two hundred year variation of southern red spruce radial growth as estimate by spectral analysis: Reply

1994 ◽  
Vol 24 (11) ◽  
pp. 2305-2311 ◽  
Author(s):  
Gregory A. Reams ◽  
N.S. Nicholas ◽  
S.M. Zedaker
Keyword(s):  
Spectral Analysis ◽  
Radial Growth ◽  
Red Spruce

not available

Ice damage in spruce–fir forests of the Black Mountains, North Carolina

1989 ◽  
Vol 19 (11) ◽  
pp. 1487-1491 ◽  
Author(s):  
N. S. Nicholas ◽  
S. M. Zedaker
Keyword(s):  
North Carolina ◽  
High Elevation ◽  
Red Spruce ◽  
Southern Appalachians ◽  
Eastern North America ◽  
Ecosystem Monitoring ◽  
Fraser Fir ◽  
Average Decrease ◽  
Ice Storms ◽  
Second Growth

Spruce–fir ecosystem monitoring was initiated in 1985 in the southern Appalachians, United States, after reports of a red spruce (Picearubens Sarg.) decline in the northeast. Ice storms during the winter of 1986–1987 had a severe impact on spruce–fir forests in the Black Mountains of North Carolina, the location of Mount Mitchell, the highest peak in eastern North America. Mortality rates were higher for red spruce than for Fraser fir (Abiesfraseri (Pursh.) Poir.), 8.1 and 2.4%, respectively. Recent ice damage was apparent in 12.4% of surviving overstory stems, with red spruce having a 17% average decrease in height. Frequency of damage to stems tended to increase with increasing elevation. Little is known about the successional dynamics of southern high elevation montane second-growth forests. Our results suggest that ice storms may be an important cause of damage and mortality.

Some Mellin-type Definite Integrals Involving Sine and Cosine Functions

2019 ◽  
Vol 10 (1) ◽  
pp. 222-237
Author(s):  
M. I. Qureshi ◽  
Kaleem A. Quraishi ◽  
Dilshad Ahamad
Keyword(s):  
Definite Integrals ◽  
Sine And Cosine Functions ◽  
Cosine Functions

Tree growth across the Nepal Himalaya during the last four centuries

2017 ◽  
Vol 41 (4) ◽  
pp. 478-495 ◽  
Author(s):  
UK Thapa ◽  
S St. George ◽  
DK Kharal ◽  
NP Gaire
Keyword(s):  
Tree Ring ◽  
Tree Growth ◽  
Environmental Changes ◽  
Ring Width ◽  
High Elevation ◽  
Forest Growth ◽  
Tree Ring Width ◽  
Early 19Th Century ◽  
Tree Ring Data ◽  
Instrumental Records

The climate of Nepal has changed rapidly over the recent decades, but most instrumental records of weather and hydrology only extend back to the 1980s. Tree rings can provide a longer perspective on recent environmental changes, and since the early 2000s, a new round of field initiatives by international researchers and Nepali scientists have more than doubled the size of the country’s tree-ring network. In this paper, we present a comprehensive analysis of the current tree-ring width network for Nepal, and use this network to estimate changes in forest growth nation-wide during the last four centuries. Ring-width chronologies in Nepal have been developed from 11 tree species, and half of the records span at least 290 years. The Nepal tree-ring width network provides a robust estimate of annual forest growth over roughly the last four centuries, but prior to this point, our mean ring-width composite fluctuates wildly due to low sample replication. Over the last four centuries, two major events are prominent in the all-Nepal composite: (i) a prolonged and widespread growth suppression during the early 1800s; and (ii) heightened growth during the most recent decade. The early 19th century decline in tree growth coincides with two major Indonesian eruptions, and suggests that short-term disturbances related to climate extremes can exert a lasting influence on the vigor of Nepal’s forests. Growth increases since AD 2000 are mainly apparent in high-elevation fir, which may be a consequence of the observed trend towards warmer temperatures, particularly during winter. This synthesis effort should be useful to establish baselines for tree-ring data in Nepal and provide a broader context to evaluate the sensitivity or behavior of this proxy in the central Himalayas.

scholarly journals The Tangential Force Affecting the Radial Baffles in a Stirred Vessel: Analysis of the Macro-instability Related Component

10.14311/450 ◽  
2003 ◽  
Vol 43 (4) ◽  
Author(s):  
P. Hasal ◽  
I. Fořt ◽  
J. Kratěna
Keyword(s):  
Experimental Data ◽  
Spectral Analysis ◽  
Tangential Force ◽  
Low Frequency ◽  
Frequency Component ◽  
Relative Magnitude ◽  
Tangential Component ◽  
Vertical Position ◽  
Total Force ◽  
Rushton Turbine

Experimental data obtained by measuring the tangential component of the force affecting radial baffles in a flat-bottomed cylindrical mixing vessel stirred with a Rushton turbine impeller is analysed. Spectral analysis of the experimental data demonstrated the presence of its macro-instability (MI) related low-frequency component embedded in the total force. Two distinct dimensionless frequencies (both directly proportional to the impeller speed of rotation N) of the occurence of the MI component were detected: a lower frequency of approximately 0.025N and a higher frequency of about 0.085N. The relative magnitude QMI of the MI-related component of the total tangential force was evaluated by a combination of proper orthogonal decomposition (POD) and spectral analysis. The values of magnitude QMI varied in the interval [rom approximately 0.05 to 0.30. The magnitude QMI takes maximum values at low Reynolds number values (in laminar and transitional regions). In the turbulent region (ReM >20000) the QMI value is low and practically constant. The dependence oj the QMI values on vertical position in the vessel is only marginal. The results suggest that the magnitude of the MI component of the force is significantly influenced by the liquid viscosity and density.

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