Fine-root turnover patterns and their relationship to root diameter and soil depth in a 14C-labeled hardwood forest
Article first published online: 4 AUG 2006
Volume 172, Issue 3, pages 523–535, November 2006
How to Cite
Joslin, J. D., Gaudinski, J. B., Torn, M. S., Riley, W. J. and Hanson, P. J. (2006), Fine-root turnover patterns and their relationship to root diameter and soil depth in a 14C-labeled hardwood forest. New Phytologist, 172: 523–535. doi: 10.1111/j.1469-8137.2006.01847.x
- Issue published online: 4 AUG 2006
- Article first published online: 4 AUG 2006
- Received: 9 May 2006 Accepted: 15 June 2006
Vol. 173, Issue 2, 445, Article first published online: 19 DEC 2006
- carbon cycling;
- fine-root lifespan;
- fine-root turnover;
- live fine-root turnover time;
- root biomass;
- root diameter;
- root mortality
- • 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 Δ14C 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 Δ14C 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.