The objective of this project is to examine how xylem anatomy and carbon allocation tradeoffs between hydraulic safety, pest defense, and reproduction affect conifer survival, growth, and fitness during and after a severe drought. Increasing intensity and severity of drought is expected in many regions under climate change. Improving mechanistic understanding of drought response at scales ranging from the cell to the forest stand will enhance our ability to predict shifts in forest composition and structure. This project is a collaborative effort between my lab and that of Prof. Emily Moran at UC Merced.

The evolution of water transport is defined by the increasing specialization of tracheary elements into tracheids and vessels, and also to a large extent, the evolution of woodiness. Modern conifers and angiosperms have evolved a suite of traits that enabled their success in habitats around the globe. But what about other lineages, such as ferns? Our work over the past twelve years has delved into the structure-function relationships of xylem belonging to these seed-free vascular plants. The vast majority of ferns lack vessels and have lost their ability to produce wood and yet they are diverse and successful on almost all substrates in habitats around the globe. How do they do it? 

Climate change is an ever-growing threat to agricultural production, as rising temperatures and drought conditions are predicted to lead to a decrease in crop growth and fruit yields (IPCC, 2022). To contend with these predictions, our research aims to understand the physiological mechanisms involved in crop growth and development under harsh conditions. For example, why is it that some varieties of strawberries grow more favorable fruits than other varieties grown within the same plot site? What morphological and physiological traits contribute to more drought-resistant plants with higher and more marketable fruit yields? This new area of research for our lab is spearheaded by Vidi Castro.

Plant species do not grow in a vacuum, but rather have co-evolved within a community of plant and herbivore species. How plants respond to stimuli depends largely on those community interactions in addition to species-specific traits. Furthermore, many parts of the world are experiencing increased drought and fire severity from a changing climate, and the community composition and species adaptations can play key roles in successful resilience to shifting habitat conditions. Our lab seeks to uncover how the interplay of ecophysiology and community dynamics converge to shape plant functional responses to their surroundings, particularly on the interaction of drought stress physiology and fire severity on species recovery to disturbance. We also seek to understand how microclimate interactions, such as temperature and relative humidity, shape functional trait development for recovering plant species following large-scale ecological disturbances. This project is lead by Hugh Leonard.