We are working in Yellowstone National Park to determine how initial post-fire structural heterogeneity controls carbon dynamics over the full cycle of individual forest stands, and how climate-mediated changes in the fire regime could potentially alter the behavior of the entire Yellowstone ecosystem as a net sink or net source in the global carbon cycle. The main objective of our project is to estimate how changes in fire frequency, pattern, and intensity will alter the distribution of forest age and structure across a landscape and how these changes, in turn, will affect the landscape carbon balance. We are using a combination of field measurements and modeling to determine how changes in climate and fire frequency will change landscape patterns of stand age and tree density, and how these landscape patterns alter carbon storage for the landscape. We are working to describe changes in all of the major pools and fluxes of the C cycle at temporal scales ranging from years to centuries, as influenced by periodic fires and different patterns of regeneration within a landscape where fire frequency will likely accompany changes in global climate, and can potentially alter C cycling dramatically.