Biogeochemistry

, Volume 104, Issue 1–3, pp 91–102

Does the age of fine root carbon indicate the age of fine roots in boreal forests?

  • S. P. Sah
  • H. Jungner
  • M. Oinonen
  • M. Kukkola
  • H.-S. Helmisaari
Article

Abstract

To test the reliability of the radiocarbon method for determining root age, we analyzed fine roots (originating from the years 1985–1993) from ingrowth cores with known maximum root age (1–6 years old). For this purpose, three Scots pine (Pinus sylvestris L.) stands were selected from boreal forests in Finland. We analyzed root 14C age by the radiocarbon method and compared it with the above-mentioned known maximum fine root age. In general, ages determined by the two methods (root 14C age and ingrowth core root maximum age) were in agreement with each other for roots of small diameter (<0.5 mm). By contrast, in most of the samples of fine roots of larger diameter (1.5–2 mm), the 14C age of root samples of 1987–1989 exceeded the ingrowth core root maximum age by 1–10 years. This shows that these roots had received a large amount of older stored carbon from unknown sources in addition to atmospheric CO2 directly from photosynthesis. We conclude that the 14C signature of fine roots, especially those of larger diameter, may not always be indicative of root age, and that further studies are needed concerning the extent of possible root uptake of older carbon and its residence time in roots.

Keywords

Fine root age Pinus sylvestris Radiocarbon Root carbon Ingrowth cores Tree ring 

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • S. P. Sah
    • 1
  • H. Jungner
    • 2
  • M. Oinonen
    • 2
  • M. Kukkola
    • 1
  • H.-S. Helmisaari
    • 1
  1. 1. Finnish Forest Research Institute (METLA), Vantaa Research UnitVantaaFinland
  2. 2.Finnish Museum of Natural History, Dating LaboratoryUniversity of HelsinkiHelsinkiFinland

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