Fine root heterogeneity by branch order: exploring the discrepancy in root turnover estimates between minirhizotron and carbon isotopic methods
- Guo, Dali
- Li, Harbin
- Mitchell, Robert J.
- Han, Wenxuan
- Hendricks, Joseph J.
- Fahey, Timothy J.
- Hendrick, Ronald L.
DOIAbstract
Fine roots constitute a large and dynamic component of the carbon cycles of terrestrial ecosystems. The reported fivefold discrepancy in turnover estimates between median longevity (ML) from minirhizotrons and mean residence time (MRT) using carbon isotopes may have global consequences. Here, a root branch order-based model and a simulated factorial experiment were used to examine four sources of error. Inherent differences between ML, a number-based measure, and MRT, a mass-based measure, and the inability of the MRT method to account for multiple replacements of rapidly cycling roots were the two sources of error that contributed more to the disparity than did the improper choice of root age distribution models and sampling bias. Se...
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