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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Publications at this Location » Publication #222525
Title: Fine root production across a primary successional ecosystem chronosequence at Mt. Shasta, California.

Author
item Uselman, Shauna
item QUALLS, ROBERT - UNIVERSITY OF NEVADA RENO
item LILIENFEIN, JULIANE - DESERT RESEARCH INST.-UNR

Submitted to: Ecosystems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2007
Publication Date: 8/22/2007
Citation: Uselman, S.M., Qualls, R.G., Lilienfein, J. 2007. Fine root production across a primary successional ecosystem chronosequence at Mt. Shasta, California. Ecosystems. 10:703-717.

Interpretive Summary: The belowground component of plant productivity is often ignored in ecosystem studies. The aim of this study was to assess fine root production and to understand how it changes as an ecosystem develops through time. Results showed that fine root production increased with ecosystem age, whereas aboveground litterfall tended to decrease. These trends suggest that fine root production represents an important nutrient input to soils, thus increasing soil fertility, and that this contribution becomes increasingly important during ecosystem development.

Technical Abstract: Estimating changes in belowground biomass and production is essential for understanding fundamental patterns and processes during ecosystem development. We examined patterns of fine root production, aboveground litterfall, and forest floor accumulation during forest primary succession at the Mt. Shasta Mudflows ecosystem chronosequence. Fine root production was measured using the root ingrowth cores method over one year, and aboveground litterfall was collected over two years. Fine root production increased significantly with ecosystem age, but only the youngest ecosystem was significantly different from all of the older ecosystems. Root production was 44.5 +/- 13.3, 168.3 +/- 20.6, 190.5 +/- 33.8, and 236.3 +/- 65.4 g m-2 year-1 in the 77, 255, 616, and >850 year-old ecosystems, respectively. Generally, aboveground litterfall and forest floor accumulation did not follow the same pattern as root production. The relative contribution of fine root production to total fine detrital production increased significantly with ecosystem age, from 14% to 49%, but only the youngest ecosystem was significantly different from all of the older ecosystems. Fine root production was significantly correlated with some measures of soil fertility but was not correlated with leaf or total litterfall, or forest floor accumulation. It was best predicted by soil N concentration alone, but this relationship may not be causal, as soil N concentration was also correlated with ecosystem age. For the oldest ecosystem, fine root production was also measured using the sequential intact cores/compartment-flow model method, and the difference between the two estimates was not significant. Our study suggests that the relative contribution of fine roots to fine detrital production, and hence to soil organic matter accumulation, may increase during forest primary succession.