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  • NPP  (2)
  • Nitrification  (2)
  • Springer  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Estimating regional forest productivity and water yield using an ecosystem model linked to a GIS (1998)
    Springer
    Landscape ecology 13 (1998), S. 323-334 
    Details
    ISSN: 1572-9761
    Keywords: forest productivity ; NPP ; runoff ; climate ; nitrogen ; northeastern U.S. ; modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We used the PnET-II model of forest carbon and water balances to estimate regional forest productivity and runoff for the northeastern United States. The model was run at 30 arc sec resolution (approximately 1 km) in conjunction with a Geographic Information System that contained monthly climate data and a satellite-derived land cover map. Predicted net primary production (NPP) ranged from 700 to 1450 g m2 yr1 with a regional mean of 1084 g m2 yr1. Validation at a number of locations within the region showed close agreement between predicted and observed values. Disagreement at two sites was proportional to differences between measured foliar N concentrations and values used in the model. Predicted runoff ranged from 24 to 150 cm yr1with a regional mean of 63 cm yr1. Predictions agreed well with observed values from U.S. Geologic Survey watersheds across the region although there was a slight bias towards overprediction at high elevations and underprediction at lower elevations. Spatial patterns in NPP followed patterns of precipitation and growing degree days, depending on the degree of predicted water versus energy limitation within each forest type. Randomized sensitivity analyses indicated that NPP within hardwood and pine forests was limited by variables controlling water availability (precipitation and soil water holding capacity) to a greater extent than foliar nitrogen, suggesting greater limitations by water than nitrogen for these forest types. In contrast, spruce-fir NPP was not sensitive to water availability and was highly sensitivity to foliar N, indicating greater limitation by available nitrogen. Although more work is needed to fully understand the relative importance of water versus nitrogen limitation in northeastern forests, these results suggests that spatial patterns of NPP for hardwoods and pines can be largely captured using currently available data sets, while substantial uncertainties exist for spruce-fir.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008004423783
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Seasonal patterns of ammonium and nitrate uptake in nine temperate forest ecosystems (1984)
    Springer
    Plant and soil 80 (1984), S. 321-335 
    Details
    ISSN: 1573-5036
    Keywords: Alfisol ; Ammonification ; Nitrification ; Nitrogen mineralization ; Temperate forests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seasonal patterns of net N mineralization and nitrification in the 0–10 cm mineral soil of 9 temperate forest sites were analyzed using approximately monthlyin situ soil incubations. Measured nitrification rates in incubated soils were found to be good estimates of nitrification in surrounding forest soils. Monthly net N mineralization rates and pools of ammonium-N in soil fluctuated during the growing season at all sites. Nitrate-N pools in soil were generally smaller than ammonium-N pools and monthly nitrification rates were less variable than net N mineralization rates. Nitrate supplied most of the N taken up annually by vegetation at 8 of the 9 sites. Furthermore, despite the large fluctuations in ammonium-N pools and monthly net N mineralization, nitrate was taken up at relatively uniform rates during the growing season at most sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02140039
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Forest biogeochemistry and primary production altered by nitrogen saturation (1995)
    Springer
    Water, air & soil pollution 85 (1995), S. 1665-1670 
    Details
    ISSN: 1573-2932
    Keywords: NPP ; N Leaching ; Element Ratios ; Nitrification ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Results from four intensive site-level manipulations and one extensive field survey in northern temperate and boreal forests show a consistent set of responses to chronic N additions. These include 1) initial and often large increase in net N mineralization followed by decreases, 2) increases in net nitrification. 3) increases in N concentration in foliage, and 4) decreased Mg∶N and Ca∶Al ratios, and declining tree growth and vigor in all evergreen stands. These results are synthesized into a set of proposed summary relationships that define the temporal pattern of responses of N-limited systems to N additions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00477219
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    Paper (German National Licenses)
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