Atmospheric #drought i.e. high water vapor pressure deficit (#VPD) of the air is one reason for #treemortality. First tests for #VPDmanipulation at the #Pfynwald in #Switzerland - we reduce VPD in a > 100 year old Scots pine forest exposed regularly to dry air: https://www.wsl.ch/de/projekte/a-novel-approach-to-disentangle-atmospheric-and-soil-drought.html