Analysis of tree-ring chemistry to interpret variations in tree-ring growth of Larix leptolepis and Cryptomeriajaponica in relation to atmospheric environmental changes in Southern Korea

Annual tree rings may have information to help investigate the effects of environmental change caused by temperature, air pollution, and acid rain on tree growth. Annual tree ring growth in relation to environmental changes was studied by analysing the chemistry of tree rings of Larix leptolepis (L. leptolepis) and Cryptomeria japonica (C. japonica) in southern Korea. Tree ring growth (diameter, annual increments of ring area) and tree ring chemistry (δ¹³C, δ; ¹⁵N, N) concentration, and Ca/Al ratios of both species were analysed. Regression analysis was conducted between tree ring data and environmental variables. Annual tree ring growth significantly differed between the two species and increased over time (p<0.01). The growth rate of L. leptolepis (ring width and ring area) was lower than that of C. japonica. Temperature, CO₂, NO₂, and SO₂ affected (p<0.05) the tree ring area increment of C. japonica, and SO, affected (p<0.05) the tree ring area increment of L. leptolepis. The relationships of temperature, SO₂, and NO₂ concentrations with tree ring δ ¹³C of both species (p<0.05) increased C isotope discrimination (Δ) and affected tree ring growth. There was a negative correlation between annual ring area and A in tree rings of L. leptolepis (p<0.01). For C. japonica, Δ was positively correlated (p<0.01) with annual ring area. The correlation of precipitation pH with tree ring δ ¹³C, δ ¹⁵N, and N concentration of the two species (p<0.01) could provide information on N deposition due to the H⁺ input from acid rain. Tree ring δ ¹⁵N and N concentration may be useful as indicators for precipitation pH. Tree ring growth was influenced by climate change, atmosphere pollutants and precipitation pH. The effects of increased temperature, atmosphere pollutants, and acid precipitation on radial growth may reflect N deposition from fossil fuel combustion. Acid deposition at the study site affected tree ring growth and both species may be at risk from the long-term effects of acid deposition over time.