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Picea schrenkiana tree-ring chronologies development and vegetation index reconstruction for the Alatau Mountains, Central Asia

Zhang T., Zhang R., Lu B., Mambetov B. T., Kelgenbayev N., Dosmanbetov D., Maisupova B., Chen F., Yu S., Shang H., Huang L.

Geochronometria

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2018

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Vol. 45, no. 1

107--118

EN

In this study, a total of 176 tree cores from Schrenk spruce (Picea schrenkiana) were used to establish a tree-ring chronology and a 167-year July–October normalized differential vegetation index (NDVI) for the Alatau Mountains in Central Asia was reconstructed using this newly developed chronology. The tree-ring based NDVI reconstruction tracks the observed data well (r=0.577, p<0.01, n=25) and precisely captures the drought events recorded in historical documents that occurred over a large area in 1917 and 1938. After applying a 21-year moving average, three dense (1860–1870, 1891–1907, and 1950–1974) and three sparse (1871–1890, 1908–1949, and 1975–2006) vegetation coverage periods were found in this reconstruction. Spatial correlation proves that the reconstructed NDVI series contains climatic signals representative for a large area including southern Kazakhstan. Although a comparison between this reconstruction and four climatic reconstructions for southeastern Kazakhstan, Nilka (in the Ili region), the Issyk Lake, and the Aksu region reveals similar variations, the coherence between these reconstructions become weak with the increase in spatial distance from north to south. In addition to the local representation, it was also demonstrated that the newly developed NDVI index can indicate the large-scale circulations over Eurasia, with the higher NDVI associated with stronger westerly winds from the Atlantic to the Alatau Mountains, and the lower NDVI associated with the weaker winds.

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Growth responses of Norway spruce (picea abies (l.) karst.) to the climate in the south-eastern part of the Českomoravská Upland (Czech Republic)

Rybníček M., Čermák P., Kolář T., Žid T.

Geochronometria

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2012

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Vol. 39, no. 2

149-157

EN

The research was conducted in selected 80- to 110-year-old spruce stands in the south-eastern part of the Českomoravská Upland at altitudes from 350 m a.s.l. to 465 m a.s.l. The regional standard tree-ring chronology shows very low increments for years 1974, 1976 and 1992. After 1992, there is a sharp rise in increments with a climax in 1997. Afterwards, increments gradually decrease, reaching minima in 2003 and 2008. The years with low increments were also confirmed by the analysis of negative pointer years when over 80% of the analysed trees responded by a sharp decrease in increment, mainly in years 1976 and 1992. We can usually find values of monthly precipitation or monthly temperature average which can explain or help explain these falls in the radial growth. The correlations of diameter increments with average monthly precipitation gain only positive statistically significant values, namely for the months of May, June, July and August of the particular year. The correlations of diameter increments with average monthly temperatures gain only negative statistical-ly significant values, namely for the months of June, July and September of the previous year and January and August of the particular year. In the examined area there is a significant negative correlation between average temperatures and monthly precipitation in July, August and September. The results of the habitual diagnostics show that with respect to the climatic conditions the health condition of the monitored stands is relatively good. On average, the defoliation does not exceed the values as-certained in different territories of the Czech Republic.

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Radiocarbon concentration in urban area

Rakowski A. Z., Kuc T., Nakamura T., Pazdur A.

Geochronometria

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2005

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Vol. 24

63-68

EN

Radiocarbon concentration has decreased in recent years due to the exchange of 14CO2 between the atmosphere and the oceans, but also due to 12CO2 emission from burning fossil fuels. This second phenomenon known as Suess effect can be observed in the highly industrialized and/or urban areas. New data of radiocarbon concentration in tree rings from Nagoya (Central Japan) and Kraków (Poland), which covered last 20 years, were obtained recently. These data were used to find the relationship between the radiocarbon concentrations in atmosphere and biosphere. Additionally, data of radiocarbon concentration in atmospheric CO2 in Kraków were compared with those derived from annual tree rings, to calculate the time of CO2 uptake for pine trees in this region. These data show that radiocarbon concentration of the CO2 in .urban air. is systematically lower than that in "clean air". Data of radiocarbon concentration were fitted by exponential and linear functions to calculate the time of exchange and predict the future level. Using data of carbon dioxide and radiocarbon concentration from Schauinsland fossil component Cf in carbon dioxide concentration level was calculated in Nagoya and Kraków.

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Radiocarbon concentration measurements in contemporary tree rings from Upper Silesia

Rakowski A. Z., Pawełczyk S., Pazdur A.

Geochronometria

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2000

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Vol. 18

19-22

EN

Upper Silesia is an example of the most industrially changed natural environment in Poland. This state is a consequence of mining development in the last 150 years as well as accumulation of a number of towns and industrial companies with high impact to the environment. A decrease of radiocarbon concentration resulted from the "Suess effect" was observed in the Upper Silesia region. Estimation of this effect, on the basis of carbon isotope analysis in annual tree rings collected from trees growing in the region considered, has been carried out.