Nathan McDowell
Washington State University, WA·Ecology & Evolution
Air around the world is getting drier. Scientists measure this dryness as vapor pressure deficit (VPD), roughly how strongly the air pulls water out of leaves.
- Fields
Ecology & Evolution
Plant Science & Agriculture
Earth & Environmental Science
- Topics
vapor pressure deficit
atmospheric drought
soil drought
- Grants
- 1 known grant, through Jul 2030
What they work on
- Identify the mechanisms behind differences among tree species in how rising vapor pressure deficit (VPD), or air dryness, affects gas exchange, growth, mortality, and ecosystem carbon and water fluxes, using seedling experiments and global tree growth datasets.
- Determine how VPD effects interact with soil drought, including through the first in-vivo VPD and soil-drought manipulation in a mature Swiss forest.
- Test whether and how quickly trees acclimate to rising VPD, meaning adjust their functional traits, and whether acclimation lessens the impact of extreme events compared with a gradual rise.
- Develop mechanistic and AI-assisted models that scale VPD effects from leaves and minutes to forests and decades to improve Earth-system model projections.
More about the research
Rising VPD can affect nearly everything a forest does, from leaf photosynthesis to tree growth, tree death, and how much carbon and water whole forests exchange with the air. Yet these effects remain poorly understood. Several questions are still open. How do different tree species in different places respond? Does dry soil make the effect worse? Can trees adjust over time? How do quick, small-scale leaf responses add up to decades-long changes in whole forests? Without answers, forest responses are hard to predict and manage.
Why it matters
Forests supply timber and water and help regulate the climate, but managers cannot yet predict how they will fare as the air keeps drying. Better understanding of which trees suffer from high VPD, when, and whether they can adjust could improve forecasts of tree death, forest growth, and carbon and water cycles. Those forecasts could support forest management decisions in the United States and Switzerland.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Paulo Brando
Yale University, CT·Ecology & Evolution
Extend a 21-year record of tree growth, mortality, biomass, canopy cover, soil moisture and forest–atmosphere carbon and water exchange at Tanguro, Brazil, to 27 years, to track recovery after repeated fire, drought and windthrow.
Jessica Gersony
Smith College, MA·Plant Science & Agriculture
Quantify phloem function, the tree's sugar-transport system, in mature forest trees under control and drought conditions, using a forest rainfall-manipulation experiment and Raman spectroscopy to visualize sugars in plant tissue.
Frank Jones
Oregon State University, OR·Ecology & Evolution
Test whether feedback between adult trees and same-species seedlings shifts from negative to positive as drought and nutrient stress increase, mediated by fungal pathogens and mutualists.
The school
Washington State University: 22 labs on PI Pages, $403M a year on research, 259 research doctorates a year.
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