Correlation of short-chained carbonyls emitted from Picea abies with physiological and environmental parameters.

•  The spectrum and diurnal course of carbonyl exchange of mature Norway spruce (Picea abies) was analysed in a temperate forest and under controlled conditions. In parallel, plant physiological and meteorological parameters were determined. •  Spruce emitted acetaldehyde, formaldehyde and acetone under field and laboratory conditions. •  Carbonyl emissions were highest at midday, for acetaldehyde amounting up to 100 nmol m-2  min-1 . During darkness uptake was also observed. Fumigation of spruce seedlings with acetaldehyde indicated a compensation point of c. 6 ppb. The exchange rates were strongly correlated with temperature and mass flow of ethanol in the xylem sap. The studies further indicated that the height of a twig on the tree affects its carbonyl emission rates. •  The present findings support the view that acetaldehyde emission by spruce is related to mass flow of ethanol in the xylem sap, as previously shown for tree seedlings under controlled conditions. The basis of formaldehyde and acetone emissions by spruce is still not clear and remains to be studied in further experiments.