Parameters such as crown architecture and biomass were combined with data on gas exchange, nutrient concentrations and biochemical changes to investigate the influence of air pollution in two Douglas fir stands (Garderen and Kootwijk). Most branch parts were found in the middle level on third-order branches: in Garderen there were twice as many as in Kootwijk and therefore there were twice as many needles. Current-year needles in the middle canopy accounted for 40% of the total number of needles. Under certain environmental conditions ozone was found to reduce photosynthetic production by 7-25%. The most significant changes in nutrients were found in the concentrations of K and Ca in the current year’s needles.

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Acta botanica neerlandica

CC BY 3.0 NL ("Naamsvermelding")

Koninklijke Nederlandse Botanische Vereniging

P.W. Evers, E.G. Steingröver, & W.W.P. Jans. (1992). Ecophysiological relations in two Douglas fir stands in the Netherlands. Acta botanica neerlandica, 41(1), 89–101.