VOLATILE ORGANIC-COMPOUND EMISSIONS FROM YOUNG BLACK SPRUCE TREES

Black spruce trees are an important component of the vast northern bor eal forest and therefore may influence global atmospheric chemistry. V ariations in the Volatile Organic Compound (VOC) emission rate of youn g (3 year old) black spruce trees as a function of light and temperatu re were found to be consistent with the functions suggested by Guenthe r et al. [:Guenther, A., Monson, R., Fall, R. (1991). Observations wit h eucalyptus and emission rate algorithm development. J. Geophys. Res. , 96(D6):10799-10808]. VOC emission rates were determined using a fast response hydrocarbon detector in conjunction with a glass cuvette. Th is allowed the VOC emission rate to be determined on a real-time basis . Summation of separate equations for isoprene and monoterpenes yielde d a predictive total VOC emission rate model as a function of light an d temperature which was based on total hydrocarbon data provided from the fast response hydrocarbon detector. Speciations of the spruce emis sions provided further evidence that temperature relationships of the isoprene and monoterpene emission rate could be fitted to the general functions proposed in the literature. The base VOC emission rate at st andard conditions was found to be 9 +/- 4 mu g C h(-1) (g dry needle w eight)(-1). (C) 1998 Elsevier Science B.V.