Abstract
Natural volatile organic compound (VOC) fluxes were measured in three U.S. woodlands in summer 1993. Fluxes from individual leaves and branches were estimated with enclosure techniques and used to initialize and evaluate VOC emission model estimates. Ambient measurements were used to estimate above canopy fluxes for entire stands and landscapes. The branch enclosure experiments revealed 78 VOCs. Hexenol derivatives were the most commonly observed oxygenated compounds. The branch measurements also revealed high rates of isoprene emission from three genera of plants (Albizia, Chusqua and Mahonia) and high rates of monoterpene emission from three genera (Atriplex, Chrysthamnus and Sorbus) for which VOC emission rates have not been reported. Measurements on an additional 34 species confirmed previous results. Leaf enclosure measurements of isoprene emission rates from Quercus were substantially higher than the rates used in existing emission models. Model predictions of diurnal variations in isoprene fluxes were generally within +/- 35% of observed flux variations. Measurements with a fast response analyzer demonstrated that 60 min is a reasonable time resolution for biogenic emission models. Average daytime stand scale (hundreds of m) flux measurements ranged from about 1.3 mg C m(-2) h(-1) for a shrub oak stand to 1.5-2.5 mg C m(-2) h(-1) for a mixed forest stand. Morning, evening and nighttime fluxes were less than 0.1 mg C m(-2) h(-1). Average daytime landscape scale (tens of km) flux measurements ranged from about 3 mg C m(-2) h(-1) for a shrub oak-aspen and rangeland landscape to about 7 mg C m(-2) h(-1) for a deciduous forest landscape. Fluxes predicted by recent versions (BEIS2, BEIS2.1) of a biogenic emission model were within 10 to 50% of observed fluxes and about 300% higher than those predicted by a previous version of the model (BEIS).
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Claims 19
Claim · model-written summary
Branch enclosures of woodland plants revealed 78 VOCs.
Verbatim
e0“Natural volatile organic compound (VOC) fluxes were measured in three U.S. woodlands in summer 1993”
e1“The branch enclosure experiments revealed 78 VOCs”
Claim · model-written summary
Hexenol derivatives were the most commonly observed oxygenated compounds in woodland branch emissions.
Verbatim
e0“Natural volatile organic compound (VOC) fluxes were measured in three U.S. woodlands in summer 1993”
e2“Hexenol derivatives were the most commonly observed oxygenated compounds”
Claim · model-written summary
Albizia showed high isoprene emission rates.
AlbiziaOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“high rates of isoprene emission from three genera of plants (Albizia, Chusqua and Mahonia)”
Claim · model-written summary
Chusqua showed high isoprene emission rates.
Verbatim
e3“high rates of isoprene emission from three genera of plants (Albizia, Chusqua and Mahonia)”
Claim · model-written summary
Mahonia showed high isoprene emission rates.
MahoniaOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“high rates of isoprene emission from three genera of plants (Albizia, Chusqua and Mahonia)”
Claim · model-written summary
Atriplex showed high monoterpene emission rates.
AtriplexOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“high rates of monoterpene emission from three genera (Atriplex, Chrysthamnus and Sorbus)”
Claim · model-written summary
Chrysthamnus showed high monoterpene emission rates.
Verbatim
e4“high rates of monoterpene emission from three genera (Atriplex, Chrysthamnus and Sorbus)”
Claim · model-written summary
Sorbus showed high monoterpene emission rates.
_29-03-2026._(d.j.b).jpg?width=60){kind=small}
SorbusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
_29-03-2026._(d.j.b).jpg?width=500)
Verbatim
e4“high rates of monoterpene emission from three genera (Atriplex, Chrysthamnus and Sorbus)”
Claim · model-written summary
Measurements on 34 additional species confirmed previous VOC emission results.
Verbatim
e5“Measurements on an additional 34 species confirmed previous results”
Claim · model-written summary
Leaf enclosure isoprene emission rates from Quercus were substantially higher than the rates used in existing emission models.
- Outcome
- isoprene emission ratese6
- Direction
- substantially highere6
- Comparator
- the rates used in existing emission modelse6
QuercusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“Leaf enclosure measurements of isoprene emission rates from Quercus were substantially higher than the rates used in existing emission models”
Claim · model-written summary
Model predictions of diurnal isoprene flux variations were within ±35% of observed variations.
Verbatim
e7“Model predictions of diurnal variations in isoprene fluxes were generally within +/- 35% of observed flux variations”
Claim · model-written summary
A 60 min time resolution is reasonable for biogenic emission models.
Not reportedComparator
Verbatim
e7“Measurements with a fast response analyzer demonstrated that 60 min is a reasonable time resolution for biogenic emission models”
Claim · model-written summary
Average daytime stand-scale flux over a shrub oak stand was 1.3 mg C m(-2) h(-1).
Verbatim
e0“Natural volatile organic compound (VOC) fluxes were measured in three U.S. woodlands in summer 1993”
e1“Average daytime stand scale (hundreds of m) flux measurements ranged from about 1.3 mg C m(-2) h(-1) for a shrub oak stand to 1.5-2.5 mg C m(-2) h(-1) for a mixed forest stand”
Claim · model-written summary
Average daytime stand-scale flux over a mixed forest stand was 1.5-2.5 mg C m(-2) h(-1).
Verbatim
e0“Natural volatile organic compound (VOC) fluxes were measured in three U.S. woodlands in summer 1993”
e1“Average daytime stand scale (hundreds of m) flux measurements ranged from about 1.3 mg C m(-2) h(-1) for a shrub oak stand to 1.5-2.5 mg C m(-2) h(-1) for a mixed forest stand”
Claim · model-written summary
Morning, evening and nighttime fluxes from woodlands were less than 0.1 mg C m(-2) h(-1).
Verbatim
e0“Natural volatile organic compound (VOC) fluxes were measured in three U.S. woodlands in summer 1993”
e2“Morning, evening and nighttime fluxes were less than 0.1 mg C m(-2) h(-1)”
Claim · model-written summary
Average daytime landscape-scale flux over a shrub oak-aspen and rangeland landscape was about 3 mg C m(-2) h(-1).
Verbatim
e1“Average daytime landscape scale (tens of km) flux measurements ranged from about 3 mg C m(-2) h(-1) for a shrub oak-aspen and rangeland landscape to about 7 mg C m(-2) h(-1) for a deciduous forest landscape”
Claim · model-written summary
Average daytime landscape-scale flux over a deciduous forest landscape was about 7 mg C m(-2) h(-1).
Verbatim
e1“Average daytime landscape scale (tens of km) flux measurements ranged from about 3 mg C m(-2) h(-1) for a shrub oak-aspen and rangeland landscape to about 7 mg C m(-2) h(-1) for a deciduous forest landscape”
Claim · model-written summary
BEIS2 and BEIS2.1 predicted fluxes within 10 to 50% of observed fluxes.
Verbatim
e0“Fluxes predicted by recent versions (BEIS2, BEIS2.1) of a biogenic emission model were within 10 to 50% of observed fluxes”
Claim · model-written summary
Fluxes predicted by BEIS2 versions were about 300% higher than those of the previous BEIS model.
Verbatim
e0“Fluxes predicted by recent versions (BEIS2, BEIS2.1) of a biogenic emission model were within 10 to 50% of observed fluxes”
e1“and about 300% higher than those predicted by a previous version of the model (BEIS)”