Monoterpene emissions from Scots pine and Norwegian spruce
- Stockholm Univ. (Sweden)
Rates of monoterpene emissions from Scots pine (Pinus sylvestris) and Norwegian spruce (Picea abies) have been measured at four sites in Sweden with a dynamic flow chamber technique. Forest floor emissions have been made in the pine forest with the static chamber technique. The compounds [Delta][sup 3]-carene and [alpha]-pinene were the predominant terpenes emitted from the crown and floor of the Scots pine forest. Alpha-pinene was the main terpene emitted from Norwegian spruce at the sites in southern and central Sweden, while [Delta][sup 3]-carene was predominant at the northern site. Emission rates, normalized to temperature, were seen to vary diurnally with a maximum at midday, and seasonally with maxima in early May and October, and a summer maximum in June-July. The possible dependence of the emission rate on needle growth rate and other plant-physiological processes is discussed. A higher emission rate and different relative composition of the emission was seen to occur when the vegetation was wet, as compared to dry vegetation. The emission from the pine forest floor was seen to have a composition different from that of the crown and a seasonality of the rate similar to that of the crown. The ground emission could not be explained by sources in the litter or ground vegetation alone, and it is suggested that the root system of the trees is also an emission source. The emission rate from the pine forest floor was of the order of 30% of the crown emission. The July rate of emission from the crown of Scots pine, normalized to 20[degrees]C and averaged over four sites in Sweden, was 0.8 [plus minus] 0.4 [mu]g (gdw (grams dry weight) h)[sup [minus]1], and for Norwegian spruce, 0.5 [plus minus] 0.7 [mu]g(gdw h)[sup [minus]1]. It would seem that previous regional and global estimates of hydrocarbon fluxes to the atmosphere have used emission factors which are too high for boreal coniferous forests. 52 refs., 8 figs., 9 tabs.
- OSTI ID:
- 6720250
- Journal Information:
- Journal of Geophysical Research; (United States), Vol. 98:D2; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FORESTS
TERPENES
EMISSION
SAMPLING
DAILY VARIATIONS
DETECTION
EARTH ATMOSPHERE
GLOBAL ASPECTS
GROWTH
HYDROCARBONS
PINES
SEASONAL VARIATIONS
SPRUCES
SWEDEN
WEIGHT
CONIFERS
DEVELOPED COUNTRIES
EUROPE
ORGANIC COMPOUNDS
PINOPHYTA
PLANTS
SCANDINAVIA
TREES
VARIATIONS
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)
540220 - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)