Summary
The dryness of the Earth's atmosphere (vapor pressure deficit, or VPD) is increasing. Its effects on many plant processes – from leaf photosynthesis, to tree growth and mortality, to forest production and water use – remain poorly understood. How does rising VPD affect different tree species growing in different locations? How do the effects of rising VPD on plants vary depending on the amount of moisture in the soil? How much and how quickly can plants cope with changes in VPD? And how do VPD effects operating on short-term, small-scale leaf processes translate to longer-term and larger-scale
