Use of Stored Carbon Reserves in Growth of Temperate Tree Roots and Leaf Buds: Analyses Using Radiocarbon Measurements and Modeling

Journal Article · Thu Jan 01 00:00:00 EST 2009 · Global Change Biology

DOI:https://doi.org/10.1111/j.1365-2486.2008.01736.x· OSTI ID:949992

Gaudinski, Julia B. ^[1]; Torn, Margaret S. ^[2]; Riley, W. J. ^[2]; Swanston, Christopher W. ^[3]; Trumbore, Susan E. ^[4]; Majdi, H ^[5]; Dawson, Todd E. ^[6]; Hanson, Paul J ^[7]

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1. University of California, Santa Cruz
2. Lawrence Berkeley National Laboratory (LBNL)
3. Lawrence Livermore National Laboratory (LLNL)
4. University of California, Irvine
5. Swedish University of Agricultural Sciences, Upsalla, Sweden
6. University of California, Berkeley
7. ORNL

Characterizing the use of C reserves in trees is important for understanding stress responses, impacts of asynchrony between photosynthesis and growth demand, and isotopic exchanges in plant dynamic studies. Using an inadvertent, whole ecosystem radiocarbon (14C) exposure in a temperate deciduous oak forest and numerical modeling, we calculated that the mean age of stored C used to grow leaf buds and new fine root tissue is 0.5-1.0 y. The mean age of stored C used to grow new roots was about 0.7 y across a range of realistic values of 14C inputs to the system. The amount of stored C used on an annual basis to grow fine roots was between 15 and 55% of total root growth, with the range defined by the assumed 14C input profile. We estimate the annually-averaged mean age of C in new root tissues is 1-5 months. Therefore, accounting for storage C use in isotope root models may be unnecessary in all but the fastest cycling root populations (i.e., mean age <1 y). Consistent with the whole ecosystem labeling results, we found, using "bomb-14C," that the mean C age of new root tissues in three additional forest sites (one deciduous, two coniferous) was less than 2 years. We conclude that in many ecosystem types, growth from stored C is insufficient to impact bomb-14C based estimates of long root lifetimes.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge National Environmental Research Park
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 949992
• Journal Information: Global Change Biology, Vol. 15, Issue 4; ISSN 1354-1013
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CARBON 14
FORESTS
ISOTOPIC EXCHANGE
OAKS
PHOTOSYNTHESIS
PLANT GROWTH
ROOTS
LEAVES