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Net primary production and light use efficiency in a mixed coniferous forest in Sweden
Author(s) -
LAGERGREN FREDERIK,
EKLUNDH LARS,
GRELLE ACHIM,
LUNDBLAD MATTIAS,
MÖLDER MEELIS,
LANKREIJER HARRY,
LINDROTH ANDERS
Publication year - 2005
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2004.01280.x
Subject(s) - primary production , photosynthetically active radiation , environmental science , daytime , vapour pressure deficit , atmospheric sciences , eddy covariance , zoology , ecosystem , ecology , photosynthesis , botany , biology , transpiration , geology
Simple light use efficiency ( ɛ ) models of net primary production (NPP) have recently been given great attention (NPP = ɛ × absorbed photosynthetically active radiation). The underlying relationships have, however, not been much studied on a time step less than a month. In this study daily NPP was estimated as the sum of net ecosystem exchange (NEE) and heterotrophic respiration ( R h ) of a mixed pine and spruce forest in Sweden. NEE was measured by eddy correlation technique and R h was estimated from measurements of forest floor respiration ( R f ) and the root share of R f . The total yearly NPP was on average 810 g C m −2 year −1 for 3 years and yearly ɛ was between 0.58 and 0.71 g C MJ −1 , which is high in comparison with other studies. There was a seasonal trend in ɛ with a relatively constant level of approximately 0.90 g C MJ −1 from April to September Daily NPP did not increase for daily intercepted radiation above 6 MJ m −2 d −1 , indicating that between‐years variation in NPP is not directly dependent on total Q i . The light was most efficiently used at an average daytime temperature of around 15 °C. At daytime vapour pressure deficit above 1400 Pa ɛ was reduced by approximately 50%.