Five months of BVOC flux measurements above a Pinus sylvestris forest stand in the Austrian Alps

Biogenic Volatile Organic Compounds (BVOCs) are a group of highly reactive chemical compounds that are emitted by the terrestrial biosphere. They play a crucial role in atmospheric chemistry by contributing to the formation of tropospheric ozone, secondary organic aerosols (SOA) and cloud condensation nuclei, thereby influencing both air quality and climate processes. However, quantifying their exchange between ecosystems and the atmosphere remains challenging due to the interplay of measurement complexities, heterogeneous surface properties and vegetation variability.

For about five months from summer to autumn 2025, we conducted an intensive measurement campaign to study the BVOC fluxes at the University of Innsbruck’s Forest Atmosphere Interaction Research (FAIR) field site in Mieming, Tirol, Austria. The site is characterized by a Pinus sylvestris canopy with Juniperus communis understory and is equipped with a 30 m tall flux tower, a heated Teflon sampling line, and an air-conditioned instrument container. BVOC concentrations were measured using Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS), and turbulent fluxes were calculated via the eddy covariance technique.

Here, we investigate the temporal variability and environmental controls of BVOC fluxes with a focus on mono- and sesquiterpenes at the ecosystem scale. We further evaluate how well emission patterns align with findings from a laboratory study conducted in 2024 on saplings of the dominant species at the FAIR site, and plan to assess the performance of the MEGAN 2.1 emission model in reproducing the observed flux dynamics.

Our results provide new insights into the drivers of BVOC fluxes in an alpine forest and support the improvement of biosphere–atmosphere exchange parameterizations in emission models.