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Fine‐root mortality rates in a temperate forest: estimates using radiocarbon data and numerical modeling
Author(s) -
Riley W. J.,
Gaudinski J. B.,
Torn M. S.,
Joslin J. D.,
Hanson P. J.
Publication year - 2009
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2009.02980.x
Subject(s) - primary production , temperate climate , respiration , temperate forest , environmental science , ecosystem , population , biology , carbon cycle , root system , ecology , atmospheric sciences , botany , geology , demography , sociology
Summary• We used an inadvertent whole‐ecosystem 14 C label at a temperate forest in Oak Ridge, Tennessee, USA to develop a model ( Radix 1.0) of fine‐root dynamics. Radix simulates two live‐root pools, two dead‐root pools, non‐normally distributed root mortality turnover times, a stored carbon (C) pool, and seasonal growth and respiration patterns. • We applied Radix to analyze measurements from two root size classes (< 0.5 and 0.5–2.0 mm diameter) and three soil‐depth increments (O horizon, 0–15 cm and 30–60 cm). • Predicted live‐root turnover times were < 1 yr and ∼10 yr for short‐ and long‐lived pools, respectively. Dead‐root pools had decomposition turnover times of ∼2 yr and ∼10 yr. Realistic characterization of C flows through fine roots requires a model with two live fine‐root populations, two dead fine‐root pools, and root respiration. These are the first fine‐root turnover time estimates that take into account respiration, storage, seasonal growth patterns, and non‐normal turnover time distributions. • The presence of a root population with decadal turnover times implies a lower amount of belowground net primary production used to grow fine‐root tissue than is currently predicted by models with a single annual turnover pool.