How forests smell - a risk for the climate?

Measurements at the MyDiv site in Bad Lauchstädt in September 2022. Photo: TROPOS - Plants emit odours for a variety of reasons, such as to communicate with each other, to deter herbivores or to respond to changing environmental conditions. An interdisciplinary team of researchers from Leipzig University, the Leibniz Institute for Tropospheric Research (TROPOS) and the German Centre for Integrative Biodiversity Research (iDiv) carried out a study to investigate how biodiversity influences the emission of these substances. For the first time, they were able to show that species-rich forests emit less of these gases into the atmosphere than monocultures. In the past, it was assumed that forests with more species would release more emissions. Experiments by the Leipzig team have now disproved this assumption. Their study has been published in the journal "Communications Earth & Environment". Plant odours penetrate the atmosphere. Plants produce a variety of organic compounds to communicate with each other and with their environment. These are known as biogenic volatile organic compounds (BVOCs), such as terpenes, which give plants their characteristic scent and help to repel pests. As well as acting as chemical signals, these substances play a role in regulating climate, air quality and atmospheric chemistry. This is because these BVOCs emitted by plants form biogenic secondary organic aerosols (BSOAs) in the air, i.e. particles in the atmosphere. These aerosols in turn affect air quality, cloud formation and the climate. MyDiv Experiment: Measurements in plots with different tree species. But how do emissions and concentrations of aerosols in the air change as biodiversity declines or plants are stressed by drought?