Reconstruction of Precipitation in Morocco Since 1100 A.D. Based on Cedrus Atlantica Tree-Ring Widths

1990 ◽  
Vol 33 (3) ◽  
pp. 337-351 ◽  
Author(s):  
Claudine Till ◽  
Joël Guiot
Keyword(s):  
Tree Ring ◽  
Arid Regions ◽  
Bootstrap Method ◽  
Ring Width ◽  
Modern Times ◽  
Cedrus Atlantica ◽  
Time Period ◽  
Precipitation Variation ◽  
The Bootstrap Method ◽  
Past 1000 Years

AbstractAnnual (October through September) precipitation from 1100 A.D. to modern times is reconstructed for Morocco, using Cedrus atlantica (Endl.) Carrière tree-ring chronologies. Both multiple regression on principal components and the bootstrap method are use to calibrate tree-ring width with precipitation; precipitation variation is reconstructed for three climatically distinct areas: the humid, subhumid, and arid regions of Morocco. A series of successive wet and dry periods is identified for the past 1000 years; the maximum length of the 13 dry periods (during which precipitation was at least 1σ below normal) is 6 years. Twenty-one years are identified during which precipitation fell more than 2σ below normal. We are unable to identify significant correspondence in climatic variation in Morocco, Europe, and the Sahel during this time period.

scholarly journals The Relationship between Tree-Ring Growths of Pinus densiflora and Climate from Three Mountains in Central Region, the Republic of Korea

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 878
Author(s):  
Chang-Hyun Park ◽  
Ui-Cheon Lee ◽  
Soo-Chul Kim ◽  
Kwang-Hee Lee
Keyword(s):  
Tree Ring ◽  
National Parks ◽  
Central Region ◽  
Climatic Factors ◽  
Pinus Densiflora ◽  
Ring Width ◽  
Republic Of Korea ◽  
Logarithmic Curve ◽  
The Republic ◽  
The Relationship

To analyze the relationship between climatic factors (monthly mean temperature and total precipitation) and tree-ring growths of Pinus densiflora from the central region of the Republic of Korea, more than 20 trees were sampled from three national parks. The tree-ring chronology of Mt. Bukhan covering the period of 1917–2016 was assessed, as well as that of Mt. Seorak across 1687–2017 and Mt. Worak across 1777–2017. After cross-dating, each ring-width series was double-standardized by first fitting a logarithmic curve and then a 50 year cubic spline. Climate-growth relationships were computed with bootstrap correlation functions. The result of the analysis showed a positive response from the current March temperature and May precipitations for tree-ring growth of Pinus densiflora. It indicates that a higher temperature supply during early spring season and precipitation during cambium activity are important for radial growths of Pinus densiflora from the central region in the Republic of Korea.

Climate control of cambial dynamics and tree-ring width in two tropical pines in Thailand

2021 ◽  
Vol 303 ◽  
pp. 108394
Author(s):  
Nathsuda Pumijumnong ◽  
Piyarat Songtrirat ◽  
Supaporn Buajan ◽  
Sineenart Preechamart ◽  
Uthai Chareonwong ◽  
...  
Keyword(s):  
Tree Ring ◽  
Ring Width ◽  
Tree Ring Width ◽  
Climate Control

scholarly journals The European Heat Wave 2018: The Dendroecological Response of Oak and Spruce in Western Germany

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 283
Author(s):  
Burkhard Neuwirth ◽  
Inken Rabbel ◽  
Jörg Bendix ◽  
Heye R. Bogena ◽  
Boris Thies
Keyword(s):  
Heat Wave ◽  
Tree Ring ◽  
Sap Flow ◽  
Hot Spring ◽  
Ring Width ◽  
Deciduous Tree ◽  
Climatic Parameters ◽  
Oak Trees ◽  
Heat Response ◽  
Western Germany

The European heat wave of 2018 was characterized by extraordinarily dry and hot spring and summer conditions in many central and northern European countries. The average temperatures from June to August 2018 were the second highest since 1881. Accordingly, many plants, especially trees, were pushed to their physiological limits. However, while the drought and heat response of field crops and younger trees have been well investigated in laboratory experiments, little is known regarding the drought and heat response of mature forest trees. In this study, we compared the response of a coniferous and a deciduous tree species, located in western and central–western Germany, to the extreme environmental conditions during the European heat wave of 2018. Combining classic dendroecological techniques (tree–ring analysis) with measurements of the intra–annual stem expansion (dendrometers) and tree water uptake (sap flow sensors), we found contrasting responses of spruce and oak trees. While spruce trees developed a narrow tree ring in 2018 combined with decreasing correlations of daily sap flow and dendrometer parameters to the climatic parameters, oak trees developed a ring with above–average tree–ring width combined with increasing correlations between the daily climatic parameters and the parameters derived from sap flow and the dendrometer sensors. In conclusion, spruce trees reacted to the 2018 heat wave with the early completion of their growth activities, whereas oaks appeared to intensify their activities based on the water content in their tree stems.

scholarly journals Prospects of Using Tree-Ring Earlywood and Latewood Width for Reconstruction of Crops Yield on Example of South Siberia

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 174
Author(s):  
Elena A. Babushkina ◽  
Dina F. Zhirnova ◽  
Liliana V. Belokopytova ◽  
Nivedita Mehrotra ◽  
Santosh K. Shah ◽  
...  
Keyword(s):  
Tree Ring ◽  
Spring Barley ◽  
Ring Width ◽  
Siberian Larch ◽  
Forest Steppe ◽  
Study Region ◽  
Yield Variation ◽  
South Siberia ◽  
Crops Yield ◽  
Reconstruction Model

Improvement of dendrochronological crops yield reconstruction by separate application of earlywood and latewood width chronologies succeeded in rain-fed semiarid region. (1) Background: Tree-ring width chronologies have been successfully applied for crops yield reconstruction models. We propose application of separated earlywood and latewood width chronologies as possible predictors improving the fitness of reconstruction models. (2) Methods: The generalized yield series of main crops (spring wheat, spring barley, oats) were investigated in rain-fed and irrigated areas in semiarid steppes of South Siberia. Chronologies of earlywood, latewood, and total ring width of Siberian larch (Larix sibirica Ledeb.) growing in forest-steppe in the middle of the study area were tested as predictors of yield reconstruction models. (3) Results: In the rain-fed territory, separation of earlywood and latewood allowed increasing variation of yield explained by reconstruction model from 17.4 to 20.5%, whereas total climatic-driven component of variation was 41.5%. However, both tree-ring based models explained only 7.7% of yield variation in the irrigated territory (climate inclusion increased it to 34.8%). Low temperature sensitivity of larch growth was the main limitation of the model. A 240-year (1780–2019) history of crop failures and yield variation dynamics were estimated from the actual data and the best reconstruction model. (4) Conclusions: Presently in the study region, breeding of the environment-resistant crops varieties compensates the increase of temperature in the yield dynamics, preventing severe harvest losses. Tree-ring based reconstructions may help to understand and forecast response of the crops to the climatic variability, and also the probability of crop failures, particularly in the rain-fed territories.

scholarly journals Statistical Estimates of the Pulsar Glitch Activity

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 8
Author(s):  
Alessandro Montoli ◽  
Marco Antonelli ◽  
Brynmor Haskell ◽  
Pierre Pizzochero
Keyword(s):  
Linear Regression ◽  
Upper Bound ◽  
Bootstrap Method ◽  
Waiting Times ◽  
Statistical Estimates ◽  
Equal Variance ◽  
Linear Fit ◽  
The Moment ◽  
The Bootstrap Method

A common way to calculate the glitch activity of a pulsar is an ordinary linear regression of the observed cumulative glitch history. This method however is likely to underestimate the errors on the activity, as it implicitly assumes a (long-term) linear dependence between glitch sizes and waiting times, as well as equal variance, i.e., homoscedasticity, in the fit residuals, both assumptions that are not well justified from pulsar data. In this paper, we review the extrapolation of the glitch activity parameter and explore two alternatives: the relaxation of the homoscedasticity hypothesis in the linear fit and the use of the bootstrap technique. We find a larger uncertainty in the activity with respect to that obtained by ordinary linear regression, especially for those objects in which it can be significantly affected by a single glitch. We discuss how this affects the theoretical upper bound on the moment of inertia associated with the region of a neutron star containing the superfluid reservoir of angular momentum released in a stationary sequence of glitches. We find that this upper bound is less tight if one considers the uncertainty on the activity estimated with the bootstrap method and allows for models in which the superfluid reservoir is entirely in the crust.

Drought signals inferred from ring-width and stable carbon isotope chronologies from Thuja occidentalis trees growing at their northwestern distribution limit, central Canada

2012 ◽  
Vol 42 (3) ◽  
pp. 517-531 ◽  
Author(s):  
Robert Au ◽  
Jacques C. Tardif
Keyword(s):  
Tree Ring ◽  
Tree Rings ◽  
Stable Carbon Isotopes ◽  
Stable Carbon Isotope ◽  
Ring Width ◽  
Ring Formation ◽  
Moisture Regime ◽  
Stable Carbon ◽  
Thuja Occidentalis ◽  
Central Canada

Stable carbon isotopes (δ13C) fixed in tree rings are dependent upon environmental conditions. Old northern white-cedar ( Thuja occidentalis L.) trees were sampled at their northwestern limit of distribution in central Canada. The objectives of the study were (i) to investigate the association between tree-ring δ13C values and radial growth in addition to the response of these variables to climate, (ii) to assess site differences between two sites varying in moisture regime, and (iii) to compare tree-ring δ13C of T. occidentalis with that of other boreal tree species growing at the northern limit of their distribution in central Canada. Over 2500 tree rings comprised of 15 T. occidentalis trees were analyzed for δ13C. Annually resolved δ13C (1650–2006) and ring-width (1542–2006) chronologies were developed. During the year of ring formation, ring width was associated with spring and early-summer conditions, whereas δ13C was more indicative of overall summer conditions. However, compared with δ13C values, ring width was more often associated with climate conditions in the year prior to ring formation. Conditions conducive to moisture stress were important for both parameters. Although ring width and δ13C corresponded to the drought intervals of the 1790s, 1840s, 1890s, 1930s, and 1960–1970, ring width may be more responsive to prolonged drought than δ13C. Tree-ring δ13C could, however, provide important information regarding physiological adaptations to drought.

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