Rapid fine root disappearance in a pine woodland: a substantial carbon flux

• Published in: Canadian journal of forest research Vol. 32; no. 12; pp. 2225 - 2230
• Main Authors: Stevens, Glen N, Jones, Robert H, Mitchell, Robert J
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.12.2002; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Biological and medical sciences; Carbon; Forestry; Forests; Fundamental and applied biological sciences. Psychology; Herbivory; Mortality; Pine trees; Pines; Roots; Roots (Botany); Soils; Temperate forests; Woodlands
• ISSN: 0045-5067; 1208-6037
• DOI: 10.1139/x02-135

Fine root production and mortality are difficult to estimate accurately, because some fine roots die within days of being produced, and many apparently healthy roots disappear rapidly with no obvious period of senescence. Such root dynamics are difficult to analyze without very fine-scaled temporal observations. To capture the behavior of short-lived and rapidly disappearing roots, we sampled minirhizotron tubes weekly for 11 months in a Pinus palustris Mill. woodland. Fine root ( 2 mm diameter) length production and length mortality during this period were 1.57 ± 0.23 mm·cm –2 (mean ± SE) and 1.19 ± 0.17 mm·cm –2 , respectively. Depending on the type of estimate used, rapid disappearance accounted for between 21 and 37% of total fine root mortality. Rapidly disappearing roots had relatively short life-spans, a median of just 10.5 days. Monthly sampling of the same data set underestimated length production by 15%, overestimated median root life-span by 60%, and obscured causes of root loss. If short-lived roots are not accounted for, total net primary productivity in temperate forests may be underestimated by as much as 10%. We propose that belowground herbivory is the leading explanation for this rapid disappearance.