The Pacific Slope (California, Oregon, Washington) is a great place to do ecological research because of its many strong environmental gradients. We have been studying plant demography across elevation gradients that vary in temperature and available moisture in order to test how climate and biotic interactions combine to affect species distributions and coexistence. Our overarching question is:
How do species' demographic performance depend on broad climate gradients, landscape disturbances, and local species interactions?
There have been dramatic mortality events across much of western North America in recent years, but the long-term implications are unknown. Will these events be offset by robust growth of remaining trees and regeneration through natural recruitment? Or do these mortality events signal the beginning of range shifts and changing composition of our forests? Will seedling recruitment compensate for high mortality rates? Under what conditions? What determines seedling growth and survival rates?