Counting tree rings

A decade-long sequence of tree ring growth ring has been correlated with nuclear magnetic resonance (NMR) spectroscopy of pine trees to show how carbon metabolism in trees is changing with climate change. The international team from Austria, Sweden, and the USA examined the isotope ratio at all six individual C-H positions in glucose formed by photosynthesis in the black pine (Pinus nigra). The experiments reproduced previously known findings regarding carbon dioxide uptake but also revealed several new signals associated with subsequent metabolic processes. The work was extended to eleven additional tree species from around the world. "Our results from eleven trees species show that the carbon-13 to carbon-12 ratios at individual C-H positions leave a fingerprint of the regulation of metabolism, which seems to be similar for all species," explains Thomas Wieloch of Umeå University.