Carbon Isotopes in Tree Rings: Climate and the Suess Effect Interferences in the Last 400 Years

Abstract

New records of delta-13C and ∆14C values in annual rings of pine and oak from different sites around the world were obtained with a time resolution of 1 yr. The results obtained for Europe (Poland), east Asia (Japan), and South America (Peru) are presented in this paper. The delta-13C and radiocarbon concentration of a-cellulose from annual tree rings of pine and of the latewood of oak were measured by both accelerator mass spectrometry (AMS) and liquid scintillation spectrometry (LSC). The values of 14S, which represent decreasing 14C concentrations caused by the emission of CO2 from fossil fuel use (Suess effect; Suess 1955), were calculated for each site. Low average 14S (about -0.4 to 0.8%) values for clean areas and high values (about 3.4-3.6%) for industrial and/or urbanized areas were noted. Records of the delta-13C values obtained for pine and oak from Poland were used to reconstruct climate changes during the last 400 yr. The results clearly indicate the climate cooling during the periods of the Maunder minimum (1645-1715) and the Dalton minimum (1790-1820). The anti-correlation between the delta-13C and ∆14C records during those 2 periods is clear if the 14C record is shifted toward older ages by 24 yr.