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Long-term summer temperature variations in the Pyrenees from detrended stable carbon isotopes

Esper J., Konter O., Krusic P. J., Saurer M., Holzkämper S., Büntgen U.

Geochronometria

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2015

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Vol. 42, no.1

53--59

EN

Substantial effort has recently been put into the development of climate reconstructions from tree-ring stable carbon isotopes, though the interpretation of long-term trends retained in such timeseries remains challenging. Here we use detrended δ13C measurements in Pinus uncinata treerings, from the Spanish Pyrenees, to reconstruct decadal variations in summer temperature back to the 13th century. The June-August temperature signal of this reconstruction is attributed using decadally as well as annually resolved, 20th century δ13C data. Results indicate that late 20th century warming has not been unique within the context of the past 750 years. Our reconstruction contains greater amplitude than previous reconstructions derived from traditional tree-ring density data, and describes particularly cool conditions during the late 19th century. Some of these differences, including early warm periods in the 14th and 17th centuries, have been retained via δ13C timeseries detrending — a novel approach in tree-ring stable isotope chronology development. The overall reduced variance in earlier studies points to an underestimation of pre-instrumental summer temperature variability derived from traditional tree-ring parameters.

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Influence of climate change on carbon and oxygen isotope fractionation factors between glucose and α-cellulose of pine wood

Sensuła B., Pazdur A.

Geochronometria

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2013

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Vol. 40, no. 2

145--152

EN

We present the first analysis of the influence of climate change on carbon and oxygen isotope fractionation factors for two saccharides (glucose and α-cellulose ) of pine wood. The conifers grew in the Niepołomice Forest in Poland and the annual rings covered a time span from 1935 to 2000 AD. Glucose samples from acid hydrolysis of α-cellulose were extracted from annual tree rings. The carbon and oxygen isotope fractionation factors between glucose and α-cellulose were not stable over time. The mean value for the carbon isotope fractionation factors between glucose and α-cellulose was greater than unity. The mean value for the oxygen isotope fractionation factors be-tween glucose and α-cellulose was lower than unity. We established, with respect to climate change, the significance of the interannual and intraannual variation in the carbon and oxygen isotope frac-tionation factors between both saccharides. We used moving interval correlation results for May of the previous year through September of the current year using a base length of 48 years. The relation-ship with summer temperature is the main climate signal in the carbon isotope fractionation factor be-tween glucose and α-cellulose. The relationship with autumn sunshine is the main climate signal in the oxygen isotope fractionation factor between glucose and α-cellulose for the tree ring chronology.

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Stable isotopes in tree rings as proxies for winter precipitation changes in the Russian Arctic over the past 150 years

Holzkämper S., Kuhry P., Kultti S., Gunnarson B., Sonninen E.

Geochronometria

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2008

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Vol. 32

37-47

EN

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.

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Hydrogen, carbon and oxygen isotopes in pine and oak tree rings from Southern Poland as climatic indicators in years 1900 - 2003

Szczepanek M., Pazdur A., Pawełczyk S., Böttger T., Haupt M., Hałas S., Bednarz Z., Krąpiec M., Szychowska-Krąpiec E.

Geochronometria

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2006

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Vol. 25

67-76

EN

Carbon, oxygen and hydrogen stable isotopes in tree rings are sensitive indicators of climate changes. We have measured carbon, oxygen and hydrogen isotope ratios in ?-cellulose extracted from annual rings of pine (Pinus sylvestris L.) and oak (Quercus robur L.) growing in the Niepołomice Forest, Southern Poland. The presented isotope records cover the period 1900-2003. In this paper we compare the values of δ13C, δ18O and δ2H observed in the wholewood of pine and in the latewood of oak with meteorological data (temperature, precipitation and sunshine). The highest significant values of correlation coefficients calculated between δ13C and the meteorological data are: -0.26 for temperature, 0.25 for precipitation and 0.41 for sunshine. On the basis of our investigations we deduced that pine is a more sensitive indicator of environmental changes than oak. Our investigation proves that the best indicators are: hydrogen for summer temperature and oxygen for summer precipitation. We noticed a rapid decrease of pine δ13C values in 1966 from -22.46‰ to -24.64‰.

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Gully erosion dating by means of anatomical changes in exposed roots (Proboszczowicka Plateau, Southern Poland)

Malik I.

Geochronometria

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2006

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Vol. 25

57-66

EN

Re-incision occurs in gullies in the undulating loess plateau in southern Poland. The gully hillslopes are mainly covered with beech trees. The beech roots are exposed in the gullies through erosion. The wood cells in the root tree rings divide into early wood and late wood, and after the roots are exposed, they start to make fewer cells. Dolomites and limestones lying under the loess cover are transported and wound the tree roots. As a result of this process on the border between exposed and unexposed tree rings in the tree roots, scars sometimes occur. These anatomical changes in root tree rings allow to date erosion episodes with one year accuracy. Dating of the exposure of roots indicates that intensive gully erosion in the studied gully started in the 1970s. Since that time, numerous extreme rainfall events responsible for initiating erosion have also occurred. The bottom of the valley head eroded during extreme rainfall events in 1984 and 1991. Erosion here alternates with deposition, its rate being relatively small. Incisions in hillslopes retreated during the flood in 1997, but they originated during earlier rainfall episodes. Hillslope undercutting occurring in the lower part of the gully was formed during older erosion episodes in 1971 and 1984.

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Carbon-13 in alpha-cellulose of oak latewood (Jędrzejów, Southern Poland) during the Maunder Minimum

Pazdur A., Korput S., Fogtman M., Szczepanek M., Hałas S., Krąpiec M., Szychowska-Krąpiec E.

Geological Quarterly

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2005

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Vol. 49, No. 2

165-172

EN

We have studied the δ13C signature in latewood alpha-cellulose of an ancient oak (Quercus robur L.) from a Cisterian Abbey belfry in Jędrzejów (Southern Poland). The time scale for the delta 13C record during 1631-1765 AD was built on the basis of detailed dendrochronology studies. Techniques available for extraction of alpha-cellulose from small samples have been used, the mean value of alpha-cellulose extraction efficiency being ca. 35%. In the delta 13C record of alpha-cellulose the cooling between 1650-1700 AD is clearly visible as a decrease of about 1.5‰. This period is consistent with the interval of the lowest solaractivity between 1645 and 1715 AD, which is known as the Maunder Minimum. Anti-correlation between δ13C and δ13C during the Maunder Minimum was observed but δ13C record is delayed by about 30 years with respect to the Maunder Minimum.