Emission of ca
rbon f
rom ecosystems in the fo
rm of volatile o
rganic compounds (VOC)
rep
resents a mino
r component flux in the global ca
rbon cycle that has a la
rge impact on g
round-level ozone, pa
rticle and ae
rosol fo
rmation and thus on ai
r chemist
ry and quality. This study
repo
rts exchanges of CO
2 and VOC between a popla
r-based sho
rt
rotation coppice (SRC) plantation and the atmosphe
re, measu
red simultaneously at two spatial scale, one at stand level and anothe
r at leaf level. The fi
rst technique combined P
roton T
ransfe
r Reaction 鈥淭ime-of-Flight鈥?mass spect
romet
ry (PTR-TOF-MS) with the eddy cova
riance method, to measu
re fluxes of a multitude of VOC. Abundant fluxes of isop
rene, methanol and, to a lesse
r extent, fluxes of othe
r oxygenated VOC such as fo
rmaldehyde, isop
rene oxidation p
roducts (methyl vinyl ketone and methac
rolein), methyl ethyl ketone, acetaldehyde, acetone and acetic acid, we
re measu
red. Unde
r optimal envi
ronmental conditions, isop
rene flux was mostly cont
rolled by tempe
ratu
re and light. Diffe
rently, methanol flux unde
rwent a combined enzymatic and stomatal cont
rol, togethe
r involving envi
ronmental d
rive
rs such as vapou
r p
ressu
re deficit (VPD), tempe
ratu
re and light intensity. Mo
reove
r fai
r weathe
r condition favou
red ozone deposition to the popla
r plantation.
The second technique involved trapping the VOCs emitted from leaves followed by gas chromatography-mass spectrometry (GC-MS) analysis. These leaf-level measurements showed that emission of isoprene in adult leaves and of monoterpenes in juvenile leaves are widespread across poplar genotypes. Detection of isoprene oxidation products (iox) emission with leaf-level measurements confirmed that a fraction of isoprene may be already oxidized within leaves, possibly when isoprene copes with foliar reactive oxygen species (ROS) formed during warm and sunny days.