Volatile Organic Compounds: mediators of forest-atmosphere interactions and indicators of forest vulnerability

Volatile organic compounds (VOCs) are important mediators of forest-atmosphere interactions, regulating plant performance and atmospheric processes. Amazonian forests comprise the dominant source of VOCs to the global atmosphere. Yet, there is a poor understanding of how VOC emissions vary in response to ecophysiological and environmental controls in Amazonian ecosystems and even less understanding of how ecosystem emissions respond to climate extremes and land use change. I will summarize my work on VOC emissions from different ecosystems and scales in the Amazon and point out that VOCs can be indicators of forest stress and, therefore, a possible metric of forest vulnerability. First, I will present the state-of-the-art of VOC emissions and their interactions with the climate system in the Amazon. Next, I will demonstrate how these interactions can differ when considering different forest types and environmental stresses, including extremes of heat and drought. Finally, I will highlight the recent progress of VOC emissions investigated in the so-called "Amazon arc of deforestation" and indicate the potential of VOCs as a metric of forest vulnerability in climate modeling.