More frequent and intense drought can have a devastating impact on forests, rendering them vulnerable to fire and disease. Caelan Simeone, a graduate student in the Geosciences Department from Bozeman, Montana, is using computer models to help scientists understand the complex relationship between climate variability, hydrology, and tree health.
Changes in the timing and the reduction of water available to plants result in hydrologic stress in vegetation, which requires increasingly higher suction forces to extract water from the soil. Higher tension increases the likelihood of cavitation (formation of bubbles) in the plant hydraulic column, reducing the efficiency with which the plant can transport water and nutrients and increasing its vulnerability to disease and fires. Caelan is teaming up with hydrologists, ecologists and plant physiologists to incorporate plant hydraulic processes into a physically based hydrologic model. The model is currently the most advanced in its category and can simulate the suction potential in tree leaves under different climate scenarios. With this information, Caelan can determine the distribution and intensity of drought-induced stress in forests, which he uses to provide insight into forest vulnerability to drought and to understand historical tree die-offs.