Abstract
Every so often, the results obtained from investigations into the effects of varying environmental conditions on the tree growth rate at the same sites and on the change in the carbon balance in plants, using traditional methods, are found to differ widely. We believe that the reason for the ambiguity of the data has to do with failure to account for the role of the residual CO2 (and H2O) in the tree wood exhibiting a climate response. In our earlier work, the results of a laser photoacoustic gas analysis of CO2 and H2O vacuum-desorbed from disc tree rings of evergreen conifer trees were presented. In this paper, laser photoacoustic measurements of tree ring gases in deciduous conifer trees and CO2 carbon isotope composition determined by means of a mass spectrometer are given. Conclusions are made regarding the response of annual larch CO2 disc tree ring distributions to climatic parameters (temperatures and precipitation). The data about the CO2 disc content for different sites are compared.
Highlights
IntroductionEnvironmental changes (temperature, atmospheric CO2 rise and variations in the CO2 carbon isotope composition) are one of the currently central problems [1]
Environmental changes are one of the currently central problems [1]
Extensive literature has been devoted to the influence of excess CO2 on the tree growth, but “there is no empirical evidence for a long-term, sustained stimulation of the tree growth by elevated CO2 in natural undisturbed setting with a natural steady state nutrient cycle” [5] (p. 1096)
Summary
Environmental changes (temperature, atmospheric CO2 rise and variations in the CO2 carbon isotope composition) are one of the currently central problems [1] An assessment of these changes with reasonable accuracy is only possible if there is information about the past climate. Since 1960, the correlation for high latitudes has been broken: while the environment temperature continued to rise, the annual tree ring width decreased, and the divergence problem, as it is called, arose [2]. Another problem was associated with the effect of the atmospheric CO2 rise (incidentally, the latter was the same everywhere) on plants. Extensive literature has been devoted to the influence of excess CO2 on the tree growth (see e.g., [4]), but “there is no empirical evidence for a long-term, sustained stimulation of the tree growth by elevated CO2 in natural undisturbed setting with a natural steady state nutrient cycle” [5] (p. 1096)
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