Robotic micromilling of tree-rings: A new tool for obtaining subseasonal environmental isotope records

High-resolution, intra-ring delta O-18, delta D, and delta C-13 values of modem tree species (Picea glauca, Larix laricina, and Populus grandidentata) were obtained using a robotic micromill. The micromilling apparatus permits accurate mapping and sampling of growth bands at a resolution of a few mu m, producing a fine, homogenous powder that facilitates chemical processing and analyses of very small aliquots of alpha-cellulose and cellulose nitrate (similar to 100 mu g). Considerable intra-ring isotope variability observed in tree samples in this study correlates with temperature and precipitation data indicating that intra-ring variability in delta O-18, delta C-13, and delta D has great potential for reconstructing high-resolution variation in meteorological conditions throughout the growing season. (C) 2008 Elsevier B.V. All rights reserved.