Document Type
Article
Date
11-2016
Keywords
coarse woody debris, decomposition, deforestation, silica
Language
English
Funder(s)
National Science Foundation, Wallenberg Foundation
Funding ID
1114804
Disciplines
Biogeochemistry | Forest Biology | Other Forestry and Forest Sciences | Soil Science | Terrestrial and Aquatic Ecology
Description/Abstract
In terrestrial ecosystems, a large portion (20–80%) of the dissolved Si (DSi) in soil solution has passed through vegetation. While the importance of this “terrestrial Si filter” is generally accepted, few data exist on the pools and fluxes of Si in forest vegetation and the rate of release of Si from decomposing plant tissues. We quantified the pools and fluxes of Si through vegetation and coarse woody debris (CWD) in a northern hardwood forest ecosystem (Watershed 6, W6) at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, USA. Previous work suggested that the decomposition of CWD may have significantly contributed to an excess of DSi reported in stream-waters following experimental deforestation of Watershed 2 (W2) at the HBEF. We found that woody biomass (wood + bark) and foliage account for approximately 65% and 31%, respectively, of the total Si in biomass at the HBEF. During the decay of American beech (Fagus grandifolia) boles, Si loss tracked the whole-bole mass loss, while yellow birch (Betula alleghaniensis) and sugar maple (Acer saccharum) decomposition resulted in a preferential Si retention of up to 30% after 16 yr. A power-law model for the changes in wood and bark Si concentrations during decomposition, in combination with an exponential model for whole-bole mass loss, successfully reproduced Si dynamics in decaying boles. Our data suggest that a minimum of 50% of the DSi annually produced in the soil of a biogeochemical reference watershed (W6) derives from biogenic Si (BSi) dissolution. The major source is fresh litter, whereas only ~2% comes from the decay of CWD. Decay of tree boles could only account for 9% of the excess DSi release observed following the experimental deforestation of W2. Therefore, elevated DSi concentrations after forest disturbance are largely derived from other sources (e.g., dissolution of BSi from forest floor soils and/or mineral weathering).
Recommended Citation
Clymans, W., D.J. Conley, J.J. Battles, P.J. Frings, M.M. Koppers, G.E. Likens, and C.E. Johnson. 2016. Silica uptake and release in live and decaying biomass in a northern hardwood forest. Ecology. 97:3044-3057.
Source
submission
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Included in
Biogeochemistry Commons, Forest Biology Commons, Other Forestry and Forest Sciences Commons, Soil Science Commons, Terrestrial and Aquatic Ecology Commons
