August 1, 2012.
Forests represent an important carbon sink that partially offsets rising levels of atmospheric CO2 (Goodale et al, 2002). Using radiocarbon measurements we assessed the age of CO2 respired from soils, tree trunks, and the whole forest canopy, to see whether any of these sources emitted older, stored carbon. Can “bomb” carbon from soils or tree trunks be detected in canopy CO2? Methodologies used were collecting tree trunk samples of 14CO2, subsurface samples were used to partition soil 14CO2 production by depth, and flask air samples of 14CO2 collected at 45ft in the atmosphere. Results presented that soil 14CO2 is modern (post-bomb) throughout the soil and . canopy 14CO2 was highly variable, and there was no obvious contributions of old-C from soil or trees. In conclusion, the 14CO2 emitted from the soil appears to be young. Future research may include more measurements of respired CO2 from tree trunks, including a larger variety of species.
Claire L. Phillips
Lawrence Livermore National Laboratory (LLNL)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013 and Grant No. 0934931. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).