scholarly journals Tree ring growth and stable isotopes as potential indicators of historical seabird activities on forested islands in coastal British Columbia

2013 ◽  
Vol 127 (2) ◽  
pp. 146 ◽  
Author(s):  
T. E. Reimchen ◽  
S. McGehee ◽  
B. W. Glickman
Keyword(s):  
British Columbia ◽  
Tree Ring ◽  
Tree Rings ◽  
Growth Period ◽  
Nitrogen Isotope ◽  
Picea Sitchensis ◽  
Isotopic Signatures ◽  
Tree Ring Data ◽  
Year 2000 ◽  
Seabird Guano

We examined yearly rings from increment cores of conifers on two seabird nesting islands (one in the Lucy Islands and one in the Rankine Islands, British Columbia), to determine whether trees contained signatures of historical activity of seabirds. Ten conifers (primarily Sitka Spruce, Picea sitchensis), ranging from 56 cm to 127 cm diameter (average 90 cm) and ranging from 70 to 232 years in age (average 132 years of age), were cored across a 200-m gradient in densities of seabird burrows. At the site in the lucy Islands, annual growth was highest (8–14 mm) in the trees with the highest seabird burrow densities and highest in the earliest rings (~1930), which were followed by a fluctuating reduction down to ~2 mm/year in the year 2000, but with a secondary elevated growth period in the 1970s. Adjacent control trees without seabird burrows had a growth rate of ~2 mm/year throughout the same period. At the site in the Rankine Islands, growth rates were also variable and exhibited a 10–15 year non-synchronous periodicity, with the highest growths in the location with high seabird burrow density. Nitrogen isotope signatures (δ15N), which are greatly elevated in seabird guano, ranged from minus 3.9% to 17.4% among tree rings (n = 245 rings) and were positively correlated to percentage nitrogen in rings, average ring growth, and burrow densities. Using these methods, we infer from our tree ring data that seabird activity declined on the lucy Islands over a 70-year period and that the combination of growth, nitrogen isotopic signatures, and percentage nitrogen in tree rings as well a more detailed sampling grid of target and adjacent control trees will provide seabird biologists with additional tools for evaluating spatial and historical trends in seabird activity on forested islands.

scholarly journals Sampling density and date influence spatial representation of tree ring reconstructions

2020 ◽  
Author(s):  
Justin T. Maxwell ◽  
Grant L. Harley ◽  
Trevis J. Matheus ◽  
Brandon M. Strange ◽  
Kayla Van Aken ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Spatial Variability ◽  
Tree Ring ◽  
Tree Rings ◽  
Large Scale ◽  
The United States ◽  
Severe Drought ◽  
Ring Network ◽  
Tree Ring Data ◽  
The Us

Abstract. Our understanding of the natural variability of hydroclimate before the instrumental period (ca. 1900 in the United States; US) is largely dependent on tree-ring-based reconstructions. Large-scale soil moisture reconstructions from a network of tree-ring chronologies have greatly improved our understanding of the spatial and temporal variability in hydroclimate conditions, particularly extremes of both drought and pluvial (wet) events. However, certain regions within these large-scale reconstructions in the US have a sparse network of tree-ring chronologies. Further, several chronologies were collected in the 1980s and 1990s, thus our understanding of the sensitivity of radial growth to soil moisture in the US is based on a period that experienced multiple extremely severe droughts and neglects the impacts of recent, rapid global change. In this study, we expanded the tree-ring network of the Ohio River Valley in the US, a region with sparse coverage. We used a total of 72 chronologies across 15 species to examine how increasing the density of the tree-ring network influences the representation of reconstructing the Palmer Meteorological Drought Index (PMDI). Further, we tested how the sampling date influenced the reconstruction models by creating reconstructions that ended in the year 1980 and compared them to reconstructions ending in 2010 from the same chronologies. We found that increasing the density of the tree-ring network resulted in reconstructed values that better matched the spatial variability of instrumentally recorded droughts and to a lesser extent, pluvials. By sampling tree in 2010 compared to 1980, the sensitivity of tree rings to PMDI decreased in the southern portion of our region where severe drought conditions have been absent over recent decades. We emphasize the need of building a high-density tree-ring network to better represent the spatial variability of past droughts and pluvials. Further, chronologies on the International Tree-Ring Data Bank need updating regularly to better understand how the sensitivity of tree rings to climate may vary through time.

scholarly journals Direct Versus Indirect Tree Ring Reconstruction of Annual Discharge of Chemora River, Algeria

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 986
Author(s):  
David M. Meko ◽  
Ramzi Touchan ◽  
Dalila Kherchouche ◽  
Said Slimani
Keyword(s):  
Error Analysis ◽  
Tree Ring ◽  
Tree Rings ◽  
Diagnostic Tool ◽  
River Discharge ◽  
Indirect Method ◽  
Modeling Approaches ◽  
Tree Ring Data ◽  
Annual Discharge ◽  
Reconstructed Precipitation

Annual river discharge is a critical variable for water resources planning and management. Tree rings are widely used to reconstruct annual discharge, but errors can be large when tree growth fails to respond commensurately to hydrologically important seasonal components of climate. This paper contrasts direct and indirect reconstruction as statistical approaches to discharge reconstruction for the Chemora River, in semi-arid northeastern Algeria, and explores indirect reconstruction as a diagnostic tool in reconstruction error analysis. We define direct reconstruction as predictions from regression of annual discharge on tree ring data, and indirect reconstruction as predictions from a four-stage process: (1) regression of precipitation on tree rings, (2) application of the regression model to get reconstructed precipitation for grid cells over the basin, (3) routing of reconstructed precipitation through a climatological water balance (WB) model, and (4) summing model runoff over cells to get the reconstructed discharge at a gage location. For comparative purposes, the potential predictors in both modeling approaches are the same principal components of tree ring width chronologies from a network of drought-sensitive sites of Pinus halepensis and Cedrus atlantica in northern Algeria. Results suggest that both modeling approaches can yield statistically significant reconstructions for the Chemora River. Greater accuracy and simplicity of the direct method are countered by conceptual physical advantages of the indirect method. The WB modeling inherent to the indirect method is useful as a diagnostic tool in error analysis of discharge reconstruction, points out the low and declining importance of snowmelt to the river discharge, and gives clues to the cause of severe underestimation of discharge in the outlier high-discharge year 1996. Results show that indirect reconstruction would benefit most in this basin from tree ring resolution of seasonal precipitation.

Chemical pretreatment of Thuja occidentalis tree rings: implications for dendroisotopic studies

2009 ◽  
Vol 39 (9) ◽  
pp. 1777-1784 ◽  
Author(s):  
Robert Au ◽  
Jacques C. Tardif
Keyword(s):  
North America ◽  
Tree Ring ◽  
Tree Rings ◽  
Cross Sections ◽  
Close Agreement ◽  
Chemical Pretreatment ◽  
Broad Distribution ◽  
Thuja Occidentalis ◽  
Wood Component ◽  
Isotopic Signatures

Whether or not extractives, lignin, and (or) hemicelluloses, all of which have specific isotopic signatures, should be removed prior to dendroisotopic analysis is still debated. This study reports the range of modern tree-ring δ13C values of cellulose from Thuja occidentalis L., a species that has been under-utilized in dendroisotopic research despite its broad distribution and great longevity in North America. The main objective of the study was to recommend a wood component from T. occidentalis to isolate for future δ13C dendroisotopic analyses. Annually resolved tree-ring decadal segments common to eight T. occidentalis trees were excised from cross sections and homogenized. The tree-ring decadal segment from each tree was then chemically processed from untreated whole wood to extractive-free wood, to holocellulose, and to α-cellulose. Subsamples were analyzed for δ13C, percent carbon, and percent yield after each stage of chemical treatment. We recommend that holocellulose be extracted for T. occidentalis, as the α-cellulose yield may be too low when tree-ring samples are very small. The δ13C values for T. occidentalis tree rings were found to be enriched with respect to those for needle-leaved conifers but in close agreement with those reported in the literature for other scale-leaved evergreens.

Dendroclimatology and Dendroecology

1971 ◽  
Vol 1 (4) ◽  
pp. 419-449 ◽  
Author(s):  
Harold C. Fritts
Keyword(s):  
Tree Ring ◽  
Tree Rings ◽  
Climatic Factors ◽  
Physiological Activity ◽  
Ring Width ◽  
Growing Season ◽  
Dry Matter Accumulation ◽  
New Developments ◽  
Cambial Age ◽  
Tree Ring Data

Dendrochronology is the science of dating annual growth layers (rings) in woody plants. Two related subdisciplines are dendroclimatology and dendroecology. The former uses the information in dated rings to study problems of present and past climates, while the latter deals with changes in the local environment rather than regional climate.Successful applications of dendroclimatology and dendroecology depend upon careful stratification. Ring-width samples are selected from trees on limiting sites, where widths of growth layers vary greatly from one year to the next (sensitivity) and autocorrelation of the widths is not high. Rings also must be cross-dated and sufficiently replicated to provide precise dating. This selection and dating assures that the climatic information common to all trees, which is analogous to the “signal”, is large and properly placed in time. The random error or nonclimatic variations in growth, among trees, is analogous to “noise” and is reduced when ring-width indices are averaged for many trees.Some basic facts about the growth are presented along with a discussion of important physiological processes operating throughout the roots, stems, and leaves. Certain gradients associated with tree height, cambial age, and physiological activity control the size of the growth layers as they vary throughout the tree. These biological gradients interact with environmental variables and complicate the task of modeling the relationships linking growth with environment.Biological models are described for the relationships between variations in ring widths from conifers on arid sites, and variations in temperature and precpitation. These climatic factors may influence the tree at any time in the year. Conditions preceding the growing season sometimes have a greater influence on ring width than conditions during the growing season, and the relative effects of these factors on growth vary with latitude, altitude, and differences in factors of the site. The effects of some climatic factors on growth are negligible during certain times of the year, but important at other times. Climatic factors are sometimes directly related to growth and at other times are inversely related to growth. Statistical methods are described for ascertaining these differences in the climatic response of trees from different sites.A practical example is given of a tree-ring study and the mechanics are described for stratification and selection of tree-ring materials, for laboratory preparation, for cross-dating, and for computer processing. Several methods for calibration of the ring-width data with climatic variation are described. The most recent is multivariate analysis, which allows simultaneous calibration of a variety of tree-ring data representing different sites with a number of variables of climate.Several examples of applications of tree-ring analysis to problems of environment and climate are described. One is a specification from tree rings of anomalies in atmosphere circulation for a portion of the Northern Hemisphere since 1700 A.D. Another example treats and specifies past conditions in terms of conditional probabilities. Other methods of comparing present climate with past climate are described along with new developments in reconstructing past hydrologic conditions from tree rings.Tree-ring studies will be applied in the future to problems of temperate and mesic environments, and to problems of physiological, genetic, and anatomical variations within and among trees. New developments in the use of X-ray techniques will facilitate the measurement and study of cell size and cell density. Tree rings are an important source of information on productivity and dry-matter accumulation at various sites. Some tree-ring studies will deal with environmental pollution. Statistical developments will improve estimation of certain past anomalies in weather factors and the reconstructtion of atmosphere circulation associated with climate variability and change. Such information should improve chances for measuring and assessing the possibility of inadvertent modification of climate by man.

Intra-annual variability in isotopic and total nitrogen in tree rings of old growth Sitka spruce from coastal British Columbia

Botany ◽  
2018 ◽  
Vol 96 (12) ◽  
pp. 851-857 ◽  
Author(s):  
T.E. Reimchen ◽  
Estelle Arbellay
Keyword(s):  
British Columbia ◽  
Tree Ring ◽  
Environmental Changes ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Wilcoxon Test ◽  
Old Growth ◽  
Ecological Processes ◽  
Annual Variability ◽  
Coastal British Columbia

Tree-ring studies using increment cores have increasingly measured elemental (N) and isotopic (δ15N) nitrogen values to evaluate environmental changes in the nitrogen cycle. The paucity of nitrogen in wood has constrained tree-ring analyses to annual resolution. Based on 77 rings and 310 sub-rings, we provide evidence for substantial intra-annual variability in N and δ15N values in the heartwood of 11 geographically widely separated, old growth Sitka spruce [Picea sitchensis (Bong.) Carrière] trees from coastal British Columbia. The range of N and δ15N values within rings (intra-annual level) was on average equal to or up to seven-times the range among rings (inter-annual level). Most rings showed a seasonal reduction in N values from early to late growth and a corresponding increase to the early growth of the following season (P < 0.05 to 0.001, Mann–Whitney–Wilcoxon test). By contrast, intra-annual changes in δ15N values were highly variable among years and among trees, ranging from pronounced oscillations (4.0‰) to reasonable consistency. Our results allude to the potential importance of such intra-ring data for interpreting seasonal trends in nitrogen use and increasing understanding of ecological processes in the marine–terrestrial interface.

scholarly journals Long-Term Effects of Climate and Competition on Radial Growth, Recovery, and Resistance in Mongolian Pines

2021 ◽  
Vol 12 ◽  
Author(s):  
ShouJia Sun ◽  
JinSong Zhang ◽  
Jia Zhou ◽  
ChongFan Guan ◽  
Shuai Lei ◽  
...  
Keyword(s):  
Tree Ring ◽  
Tree Growth ◽  
Radial Growth ◽  
Climatic Factors ◽  
Regional Scale ◽  
Growth Period ◽  
Reconstruction Method ◽  
Long Term Effects ◽  
Drought Vulnerability ◽  
Tree Ring Data

Understanding the response of tree growth and drought vulnerability to climate and competition is critical for managing plantation forests. We analyzed the growth of Mongolian pines in six forests planted by the Three-North Shelter Forest Program with tree-ring data and stand structures. A retroactive reconstruction method was used to depict the growth-competition relationships of Mongolian pines during the growth period and their climatic responses under different competition levels. Drought vulnerability was analyzed by measuring the basal area increment (BAI) of different competition indices (CIs). In young trees, differences in BAIs in stands with different CIs were not statistically significant. After 15–20 years, medium- and high-CI stands had significantly lower tree-ring widths (TWs) and BAIs than the low-CI stands (p &lt; 0.05). The standardized precipitation evapotranspiration index (SPEI), precipitation, relative humidity, and vapor pressure deficit were major factors affecting tree growth. On a regional scale, climate outweighed competition in determining radial growth. The relative contribution of climatic factors increased with the gap in SPEI between plantation sites and the native range, while the reverse pattern of the competition-growth relationship was observed. Drought reduced TWs and BAIs at all sites. Stands of different CIs exhibited similar resistance, but, compared with low-CI stands, high- and medium-CI stands had significantly lower recovery, resilience, and relative resilience, indicating they were more susceptible to drought stresses. Modeled CI was significantly negatively related to resistance, resilience, and relative resilience, indicating a density-dependence of tree response to drought. After exposure to multiple sequential drought events, the relative resilience of high-CI stands decreased to almost zero; this failure to fully recover to pre-drought growth rates suggests increased mortality in the future. In contrast, low-CI stands are more likely to survive in hotter, more arid climates. These results provide a better understanding of the roles of competition and climate on the growth of Mongolian pines and offer a new perspective for investigating the density-dependent recovery and resilience of these forests.

Use of tree ring reconstructed streamflows to assess drought

2005 ◽  
Vol 32 (6) ◽  
pp. 1114-1123 ◽  
Author(s):  
David V Bonin ◽  
Donald H Burn
Keyword(s):  
Tree Ring ◽  
Tree Rings ◽  
Investment Decision ◽  
Flow Conditions ◽  
Growth Rings ◽  
Athabasca River ◽  
Climatic Variations ◽  
Investment Decision Making ◽  
Tree Ring Data ◽  
Extreme Flow

The reconstruction of past streamflow events is of great interest to the water resources engineer to obtain the best possible estimates of extreme flow conditions for investment, decision making, and design. The tree ring data offer a unique way of addressing this problem. The pattern of growth rings of a tree reflects the environmental conditions experienced during each year. Tree rings are produced annually and can be precisely and reliably linked to climatic variations, which makes them ideal for correlation with annual climatic records. This paper demonstrates the utility of using the methods of dendroclimatology, the study of climate through tree rings, to extend streamflow records. The techniques developed were applied to the Athabasca River at Athabasca. The results reveal considerable benefits from the reconstruction through more precise, and more extreme, estimates of drought quantiles.Key words: drought, tree ring data, reconstruction, extreme flow quantiles, frequency analysis.

scholarly journals Comparing Approaches for Reconstructing Groundwater Levels in the Mountainous Regions of Interior British Columbia, Canada, Using Tree Ring Widths

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1374
Author(s):  
Stephanie C. Hunter ◽  
Diana M. Allen ◽  
Karen E. Kohfeld
Keyword(s):  
British Columbia ◽  
Tree Ring ◽  
Groundwater Level ◽  
High Elevation ◽  
Valuable Insight ◽  
Driven Systems ◽  
Groundwater Levels ◽  
Mountainous Regions ◽  
Tree Ring Data ◽  
Observation Wells

Observed groundwater level records are relatively short (<100 years), limiting long-term studies of groundwater variability that could provide valuable insight into climate change effects. This study uses tree ring data from the International Tree Ring Database (ITRDB) and groundwater level data from 22 provincial observation wells to evaluate different approaches for reconstructing groundwater levels from tree ring widths in the mountainous southern interior of British Columbia, Canada. The twenty-eight reconstruction models consider the selection of observation wells (e.g., regional average groundwater level vs. wells classified by recharge mechanism) and the search area for potential tree ring records (climate footprint vs. North American Ecoregions). Results show that if the climate footprint is used, reconstructions are statistically valid if the wells are grouped according to recharge mechanism, with streamflow-driven and high-elevation recharge-driven wells (both snowmelt-dominated) producing valid models. Of all the ecoregions considered, only the Coast Mountain Ecoregion models are statistically valid for both the regional average groundwater level and high-elevation recharge-driven systems. No model is statistically valid for low-elevation recharge-driven systems (rainfall-dominated). The longest models extend the groundwater level record to the year 1500, with the highest confidence in the later portions of the reconstructions going back to the year 1800.

scholarly journals Streamflow variability over 1881–2011 period in northern Quebec: comparison of hydrological reconstructions based on tree rings and on geopotential height field reanalysis

2016 ◽  
Author(s):  
P. Brigode ◽  
F. Brissette ◽  
A. Nicault ◽  
L. Perreault ◽  
A. Kuentz ◽  
...  
Keyword(s):  
Time Series ◽  
Interannual Variability ◽  
Tree Ring ◽  
Tree Rings ◽  
Geopotential Height ◽  
Climatic Reconstruction ◽  
Daily Streamflow ◽  
Tree Ring Data ◽  
Streamflow Variability ◽  
Climatic Time Series

Abstract. Over the last decades, different methods have been used by hydrologists to extend observed hydro-climatic time series, based on other data sources, such as tree rings or sedimentological datasets. For example, tree ring multi-proxies have been studied for the Caniapiscau Reservoir in northern Quebec (Canada), leading to the reconstruction of flow series for the last 150 years. In this paper, we applied a new hydro-climatic reconstruction method on the Caniapiscau Reservoir to compare the obtained streamflow series and study the natural streamflow variability over the 1881–2011 period. This new reconstruction is based, not on natural proxies, but on a historical reanalysis of global geopotential height fields, and aims firstly to produce daily climatic time series, which are then used as inputs to a rainfall-runoff model in order to obtain daily streamflow time series. The performances of the hydro-climatic reconstruction were quantified over the observed period, and showed good performances, both in terms of monthly regimes and interannual variability. The streamflow reconstructions were then compared to two different reconstructions performed on the same catchment by using tree ring data series, one being focused on mean annual flows, and the other one on spring floods. In terms of mean annual flows, the interannual variability of the reconstructed flows were similar (except for the 1930–1940 decade), with significant changes seen in wetter and drier years. For spring floods, the interannual variabilities reconstructed were quite similar for the 1955–2011 period, but significantly different between 1880 and 1940. The results emphasize the need to apply different reconstruction methods on the same catchments. Indeed, comparisons such as those above highlight potential differences between available reconstructions, and finally, allow a retrospective analysis of the proposed reconstructions of past hydro-climatological variabilities.

scholarly journals Floating Larch Tree-Ring Chronologies from Archaeological Timbers in the Russian Altai Between about 800 BC and AD 800

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 693-702 ◽  
Author(s):  
Irina Panyushkina ◽  
Igor Sljusarenko ◽  
Nikolay Bikov ◽  
Eugene Bogdanov
Keyword(s):  
Tree Ring ◽  
Tree Rings ◽  
Iron Age ◽  
Regional Scale ◽  
Ring Width ◽  
Tree Ring Width ◽  
Southeastern Part ◽  
Archaeological Wood ◽  
Pazyryk Culture ◽  
Tree Ring Data

We obtained over 200 archaeological wood specimens from the southeastern part of the Altai Mountains (Russia) to establish accurate calendar dates of the timbers using both radiocarbon and tree-ring analyses. Most timbers came from small and elite tombs of the Pazyryk culture (Siberian Scythians of the Iron Age period). Timbers from Hun-Sarmatian and Turk times (1st millennium AD) were studied for the first time. Three floating tree-ring width chronologies of larch (Larix sibirica) with lengths of 486 yr to 144 yr were developed from the tree-ring data. Tree rings of the composite 486-yr chronology of the Pazyryk culture represent the regional scale of Altai tree-ring width variability between about 720–240 BC. The composite chronology dates the earliest construction of Pazyryk culture tombs to ∼320 BC (ordinary tombs) and the latest ones at 240 BC (Pazyryk noble tomb #5). The composite chronology might be used for tree-ring dating wood from Scythian tombs in the region. It will also help confirm the precision of 14C dating of the Scythian tombs around the Hallstatt plateau of 14C calibration curves. We developed a 110-yr decadal 14C sequence from the Kurayka site that dates Kok-Pash culture timbers back to cal AD 240 (Hun-Sarmatian period). 14C dates of wooden poles from 3 sites of Turk stone enclosures suggested wood cutting dates between cal AD 470 and 830. The results demonstrate that crossdating tree rings along with 14C dating of crossdated rings provide the most reliable and highest precision dates for these archaeological sites.

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