Research

Understanding how global climate change impacts ecosystem structure and function is one of the greatest scientific challenges of our time. Examining how trees and forests respond to environmental change is of particular importance due to their critical role in supporting biodiversity, regulating global carbon, water, and nutrient cycles, and providing a multitude of ecosystem and social services.

Climate-related impacts have already been observed in diverse forests around the world, and are expected to become more widespread in the coming decades. Projected future climate changes, including higher temperatures and atmospheric carbon dioxide, altered precipitation patterns, greater frequency of extreme events such as heat waves and drought, and shifts in growing seasons, will have profound physical and biological effects on trees and associated forest ecosystems globally.

The overarching goal of my research is to advance our knowledge of the physiological mechanisms controlling tree performance and forest ecosystem responses to climate change. I study how uptake, transport and usage of water and carbon by trees are coordinated, and how they are affected by tree structural properties and by variability in soil and atmospheric conditions.

My research in collaboration with other scientists combines diverse methods and tools from the fields of plant physiology, forest ecosystem ecology, stable isotope biogeochemistry, dendrochronology, remote sensing, and micrometeorology. I also utilize advanced rope-based climbing techniques in order to directly study tree and forest canopy structure, function, and biological diversity.

Here are some of my current projects:

Giant sequoias in a changing climate

Giant sequoia (Sequoiadendron giganteum) is one of the most iconic species on Earth. However, the sequoias' continued health may be threatened by climate change. I am currently working with an interdisciplinary team from The Marmot Society, National Park Service, US Geological Survey, and others to understand interactions between giant sequoia tree water use, fire, and vulnerability to drought and beetle attack.

Tree water and carbon relations

All plants need an adequate supply of water to sustain their metabolism, growth and survival, and plant water and carbon relations are fundamentally linked. I have been involved in several projects examining tree water and carbon relations to gain a better understanding of these linkages, and am currently working with researchers from UC Berkeley, Cornell, Humboldt State University and Northern Arizona University to quantify environmental controls on the water status and physiology of coast redwood and coast live oak trees in California.