Internal element cycles of an old-growth Douglas-fir ecosystem in western Oregon
Information on primary production, decomposition, hydrology, and element cycling was intergrated in annual budgets of accumulation and flux among components of a mature Douglas-fir forest ecosystem. Annual N input in precipitation and dust was 2.0 kg/ha, and an estimated 2.8 kg/ha were fixed by cyanophycophilous lichens in the canopy. Annual N loss to groundwater was 1.5 kg/ha. Microparticulate litterfall provided a large input of N to the forest floor. Total annual loss to ground water was 9400 eq/ha and, because of little cation accumulation, loss exactly balanced input. Net transfers of P were small. Total annual input was 0.5 kg/ha, total loss was 0.7 kg/ha, and net accumulation was -0.2 kg/ha. Input of elements in precipitation and dryfall was small compared with that in the Eastern United States. Water chemistry profiles showed that the biologically important elements N, P, and K increased in concentration as water passed through the canopy and litter layer but decreased as water passed through the rooted part of the mineral soil. In contrast, Na increased by a factor of 20 as water passed through the rooted soil. Concentrations of all elements except Mg were lower in the stream water than in solution at 2.0-m depth in the subsoil. Total return to the forest floor in litterfall was greater than that reported for other Douglas-fir stands mainly because of plentiful microparticulate forms and coarse woody debris. Leaf fall accounted for less than half of the total litterfall input of N to the forest floor. Fluxes of hydrogen ions (H/sup +/) resulting from water flow were negligible compared with H/sup +/ release during carbonic acid dissociation and H/sup +/ removal accompanying cation release in weathering. Uptake of metalic cations by vegetation and release during decomposition exceeded uptake and release of sulfur and phophorus anions, resulting in a net H/sup +/ flux of approximately 1 x 10/sup 3/ eq x ha/yr.
- OSTI ID:
- 6094141
- Journal Information:
- Ecol. Monogr.; (United States), Vol. 50:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
CALCIUM COMPOUNDS
ECOLOGICAL CONCENTRATION
MAGNESIUM COMPOUNDS
NITROGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
POTASSIUM COMPOUNDS
SODIUM COMPOUNDS
SULFUR COMPOUNDS
AIR POLLUTION
ATMOSPHERIC PRECIPITATIONS
DECOMPOSITION
DUSTS
ENVIRONMENTAL TRANSPORT
FOLIAR UPTAKE
FOREST LITTER
HYDROLOGY
LAND POLLUTION
LICHENS
MINERAL CYCLING
NITROGEN CYCLE
OREGON
PLANTS
PRODUCTIVITY
SOILS
STREAMS
SULFUR CYCLE
TERRESTRIAL ECOSYSTEMS
WATER CHEMISTRY
WATER POLLUTION
ALGAE
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BIOLOGICAL MATERIALS
CHEMICAL REACTIONS
CHEMISTRY
ECOSYSTEMS
FEDERAL REGION X
FUNGI
MASS TRANSFER
MATERIALS
NORTH AMERICA
POLLUTION
SURFACE WATERS
UPTAKE
USA
560303* - Chemicals Metabolism & Toxicology- Plants- (-1987)
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)
520200 - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)
510200 - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)