HR: 1330h
AN: A32A-0120    [PDF]
TI: Terpene Emissions From a Deciduous Forest - Variation of Compound Composition and Emission Rates
AU: * Holzke, C
EM: c.holzke@fz-juelich.de
AF: Institute of Chemistry and Dynamics of the Geosphere (ICG-II), Research Center Juelich, Leo-Brandt-Str., Juelich, 52425 Germany
AU: Koppmann, R
EM: r.koppmann@fz-juelich.de
AF: Institute of Chemistry and Dynamics of the Geosphere (ICG-II), Research Center Juelich, Leo-Brandt-Str., Juelich, 52425 Germany
AB: Plants emit a complex mixture of volatile organic compounds (VOCs). These hydrocarbons play an important role in atmospheric chemistry because of their high chemical reactivity. Due to the complexity of the chemical system there are still large uncertainties about environmental and especially physiological influences affecting amount and pattern of these emissions. In general, VOC emissions are affected by meteorological parameters like temperature and light intensity as well as ecophysiological parameters like herbivore attack and allelopathic effects. Moreover an influence of the developmental status of the emitting plants is likely. Aim of our work was to get insight in the emission behaviour concerning terpenes by carrying out long-term measurements in the field. Applying the branch enclosure technique terpene emissions from beech (Fagus silvatica L.) were investigated for two successive vegetation periods (2002-2003). In both years main compounds emitted were the monoterpenes sabinene, alpha- and beta-pinene and tricyclene. The emission rates changed over the day up to two orders of magnitude as a function of temperature and light. While the specific emission patterns changed only little over the year, the emission rates showed significant variations. Highest emission rates were observed in summer and lowest were found in fall. However, no emissions were found in early spring although leaves were fully developed and temperature and light conditions were moderate. Moreover a seasonality characterized by a temperature independent decline of emissions in late summer was found. The results underline the importance to characterize the annual variation of emission behavior. Especially for the up-scaling to global VOC emissions, seasonal influences have to be considered to achieve realistic emission inventories.
DE: 0315 Biosphere/atmosphere interactions
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting