The availability of high-resolution global datasets has enabled many ecologists to expand their scope of inference, greatly improving our understanding of landscape-scale disturbances such as fire. Our research program, in contrast, is using “Big Data” of an entirely different sort—rather than examining fire effects across broad regions, we are using a longitudinal dataset from a large (25.6-ha) forest plot to explore the intricacies of fire-related tree mortality and interactions with climate and biotic disturbances.
The Yosemite Forest Dynamics Plot (YFDP) is an exhaustively measured forest plot containing over 34,000 trees that was established in 2010, three years before burning in the 2013 Rim Fire. For seven years following the fire, we tracked tree and shrub mortality, regeneration, surface fuels, and coarse woody debris. The large, longitudinal, and spatially explicit nature of the YFDP renders it unique among the datasets that are typically used in the field of fire ecology, and the Rim Fire provided a serendipitous opportunity to evaluate fire science tools in novel ways. This included validating post-fire mortality models, assessing uncertainty associated with Landsat-derived fire severity indices, and characterizing the ecological factors that mediate post-fire mortality of large-diameter trees.
Results/Conclusions
Fire effects models under-predicted mortality of large-diameter trees, and spatially non-random ecological processes mediated delayed mortality and contributed to patterns in expressed fire severity. There was a considerable amount of variability in tree mortality when compared with satellite-derived severity maps, contributing to uncertainty in fire effects at the landscape scale. Our research in the YFDP has evolved to follow the rapid dynamics of this post-fire forest. While much of our initial work focused on tree mortality, our current research targets the post-fire dynamics of snags, coarse woody debris, and surface fuels. The precipitous accumulation of surface fuels in recent years has motivated us to begin preparing for the inevitable reburn of the plot; our maps of surface fuels offer an exceptional opportunity to examine how heterogeneity in the structure and arrangement of fuel drives fire behavior across four orders of magnitude (sub-meter to >10 ha).
Long-term monitoring plots have earned a distinguished place among many ecological sub-disciplines by enabling direct measurements of ecological dynamics that occur on time scales greater than typical grant cycles. Longitudinal studies can provide insightful contrasts with shorter-term studies, and the past decade of research in the YFDP demonstrates the untapped potential for longitudinal research to contribute to the field of fire ecology.