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Title: Fine-root turnover patterns and their relationship to root diameter and soil depth in a 14C-labeled hardwood forest

Abstract

Characterization of turnover times of fine roots is essential to understanding patterns of carbon allocation in plants and describing forest C cycling. We used the rate of decline in the ratio of 14C to 12C in a mature hardwood forest, enriched by an inadvertent 14C pulse, to investigate fine-root turnover and its relationship with fine-root diameter and soil depth. Biomass and ?14C values were determined for fine roots collected during three consecutive winters from four sites, by depth, diameter size classes (<0.5 or 0.5-2 mm), and live-or-dead status. Live-root pools retained significant 14C enrichment over 3 yr, demonstrating a mean turnover time on the order of years. However, elevated ?14C values in dead-root pools within 18 months of the pulse indicated an additional component of live roots with short turnover times (months). Our results challenge assumptions of a single live fine-root pool with a unimodal and normal age distribution. Live fine roots <0.5 mm and those near the surface, especially those in the O horizon, had more rapid turnover than 0.5-2 mm roots and deeper roots, respectively.

Authors:
 [1];  [2];  [3];  [3];  [1]
  1. ORNL
  2. University of California, Santa Cruz
  3. Lawrence Berkeley National Laboratory (LBNL)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Oak Ridge National Environmental Research Park
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
930812
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: New Phytologist; Journal Volume: 172; Journal Issue: 3
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; BIOMASS; CARBON; DISTRIBUTION; FORESTS; SOILS

Citation Formats

Joslin, Jr., John D, Gaudinski, Julia B., Torn, Margaret S., Riley, W. J., and Hanson, Paul J. Fine-root turnover patterns and their relationship to root diameter and soil depth in a 14C-labeled hardwood forest. United States: N. p., 2006. Web. doi:10.1111/j.1469-8137.2006.01847.x.
Joslin, Jr., John D, Gaudinski, Julia B., Torn, Margaret S., Riley, W. J., & Hanson, Paul J. Fine-root turnover patterns and their relationship to root diameter and soil depth in a 14C-labeled hardwood forest. United States. doi:10.1111/j.1469-8137.2006.01847.x.
Joslin, Jr., John D, Gaudinski, Julia B., Torn, Margaret S., Riley, W. J., and Hanson, Paul J. Sun . "Fine-root turnover patterns and their relationship to root diameter and soil depth in a 14C-labeled hardwood forest". United States. doi:10.1111/j.1469-8137.2006.01847.x.
@article{osti_930812,
title = {Fine-root turnover patterns and their relationship to root diameter and soil depth in a 14C-labeled hardwood forest},
author = {Joslin, Jr., John D and Gaudinski, Julia B. and Torn, Margaret S. and Riley, W. J. and Hanson, Paul J},
abstractNote = {Characterization of turnover times of fine roots is essential to understanding patterns of carbon allocation in plants and describing forest C cycling. We used the rate of decline in the ratio of 14C to 12C in a mature hardwood forest, enriched by an inadvertent 14C pulse, to investigate fine-root turnover and its relationship with fine-root diameter and soil depth. Biomass and ?14C values were determined for fine roots collected during three consecutive winters from four sites, by depth, diameter size classes (<0.5 or 0.5-2 mm), and live-or-dead status. Live-root pools retained significant 14C enrichment over 3 yr, demonstrating a mean turnover time on the order of years. However, elevated ?14C values in dead-root pools within 18 months of the pulse indicated an additional component of live roots with short turnover times (months). Our results challenge assumptions of a single live fine-root pool with a unimodal and normal age distribution. Live fine roots <0.5 mm and those near the surface, especially those in the O horizon, had more rapid turnover than 0.5-2 mm roots and deeper roots, respectively.},
doi = {10.1111/j.1469-8137.2006.01847.x},
journal = {New Phytologist},
number = 3,
volume = 172,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}