scholarly journals Stable Isotopes in Tree Rings as Proxies for Winter Precipitation Changes in the Russian Arctic over the Past 150 Years

2008 ◽  
Vol 32 (-1) ◽  
pp. 37-46 ◽  
Author(s):  
Steffen Holzkämper ◽  
Peter Kuhry ◽  
Seija Kultti ◽  
Björn Gunnarson ◽  
Eloni Sonninen

Stable Isotopes in Tree Rings as Proxies for Winter Precipitation Changes in the Russian Arctic over the Past 150 Years We present results from an analysis of tree ring width and stable carbon and oxygen isotopes in tree ring cellulose of Siberian Spruce collected from remote forest islands in the northwestern Russian tundra. Ring width is often considered a proxy for summer temperatures. The aim of this pilot study was to test whether stable isotopes can provide additional information about climate during the growth of trees in this extreme environment. Comparison of δ13C and δ18O with observed meteorological data shows that there is a link between stable isotopes and winter precipitation. This may be explained by the strong influence that snow exerts on the isotopic composition of soil moisture during spring and early summer, when the new cellulose is formed. Our results show that winter precipitation in the study area was increasing from 1865-1900, and thereafter decreasing until ~ 1930. The 1960-1980 period was again rather humid, followed by a drying trend until 1990. The study highlights the potential of stable carbon and oxygen isotopes in tree rings as proxies for winter precipitation.

2016 ◽  
Vol 32 (3) ◽  
pp. 213-225 ◽  
Author(s):  
Daniele Colombaroli ◽  
Paolo Cherubini ◽  
Maaike De Ridder ◽  
Matthias Saurer ◽  
Benjamin Toirambe ◽  
...  

Abstract:In equatorial regions, where tree rings are less distinct or even absent, the response of forests to high-frequency climate variability is poorly understood. We measured stable carbon and oxygen isotopes in anatomically distinct, annual growth rings of four Pericopsis elata trees from a plantation in the Congo Basin, to assess their sensitivity to recorded changes in precipitation over the last 50 y. Our results suggest that oxygen isotopes have high common signal strength (EPS = 0.74), and respond to multi-annual precipitation variability at the regional scale, with low δ18O values (28–29‰) during wetter conditions (1960–1970). Conversely, δ13C are mostly related to growth variation, which in a light-demanding species are driven by competition for light. Differences in δ13C values between fast- and slow-growing trees (c. 2‰), result in low common signal strength (EPS = 0.37) and are driven by micro-site conditions rather than by climate. This study highlights the potential for understanding the causes of growth variation in P. elata as well as past hydroclimatic changes, in a climatically complex region characterized by a bimodal distribution in precipitation.


2012 ◽  
Vol 42 (3) ◽  
pp. 517-531 ◽  
Author(s):  
Robert Au ◽  
Jacques C. Tardif

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.


2018 ◽  
Vol 64 (No. 3) ◽  
pp. 139-147 ◽  
Author(s):  
Khaleghi Mohammad Reza

The present study tends to describe the survey of climatic changes in the case of the Bojnourd region of North Khorasan, Iran. Climate change due to a fragile ecosystem in semi-arid and arid regions such as Iran is one of the most challenging climatological and hydrological problems. Dendrochronology, which uses tree rings to their exact year of formation to analyse temporal and spatial patterns of processes in the physical and cultural sciences, can be used to evaluate the effects of climate change. In this study, the effects of climate change were simulated using dendrochronology (tree rings) and an artificial neural network (ANN) for the period from 1800 to 2015. The present study was executed using the Quercus castaneifolia C.A. Meyer. Tree-ring width, temperature, and precipitation were the input parameters for the study, and climate change parameters were the outputs. After the training process, the model was verified. The verified network and tree rings were used to simulate climatic parameter changes during the past times. The results showed that the integration of dendroclimatology and an ANN renders a high degree of accuracy and efficiency in the simulation of climate change. The results showed that in the last two centuries, the climate of the study area changed from semiarid to arid, and its annual precipitation decreased significantly.


2010 ◽  
Vol 270 (1-4) ◽  
pp. 216-226 ◽  
Author(s):  
Päivi Kaislahti Tillman ◽  
Steffen Holzkämper ◽  
Peter Kuhry ◽  
A. Britta K. Sannel ◽  
Neil J. Loader ◽  
...  

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