A large-scale throughfall manipulation experiment on Walker Branch Watershed
A throughfall displacement experiment is being performed in a mixed-age upland-oak forest on the upper slopes of Walker Branch Watershed in eastern Tennessee to investigate the effects of decreased and increased rainfall on individual species and ecosystem processes at the spatial scale of forest stands. Approximately 25% of the throughfall on the ``dry`` plot will be collected in polyethylene troughs suspended above the forest floor and the water transferred by gravity through pipes across the control plot for distribution onto the ``wet`` plot. Each plot is approximately 0.6 ha in size. The 25% reduction in soil moisture anticipated for the dry plot is equivalent to the driest growing season of the 1980`s drought, which was correlated with sapling mortality and reduced growth of yellow poplar on the watershed. The experimental treatments will last at least 5 years. A wide range of biological and chemical characteristics of forest stands win be investigated, including: forest growth and physiological responses of major tree and understory species, leaf area index, herbivory, litter fall, understory competition, litter decomposition, soil organic matter and microbial populations, nutrient availability, soil and soil solution chemistry, and biogeochemical cycling processes. Data on vegetation growth, mortality, and reproduction will be used in existing models of community structure to produce estimates of potential changes in species composition over longer time periods resulting from wet versus dry experimental scenarios.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10155046
- Report Number(s):
- CONF-9205194-1; ON: DE92015237
- Resource Relation:
- Conference: International symposium on experimental manipulations of biota and biogeochemical cycling in eosystems-approach, methodologies, findings,Copenhagen (Denmark),18-20 May 1992; Other Information: PBD: [1992]
- Country of Publication:
- United States
- Language:
- English
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