Carbon and charcoal in compound disturbance environments
Several fires are currently being investigators by members of the Buma lab and other collaborators at Colorado College, across the southern Rockies and soon, Alaska. We are investigating not only how compound disturbances influence carbon and charcoal, but how time since fire influences charcoal, carbon, and charcoal fluxes out of watersheds - we are doing this by expanding with aquatic biogeochemistry collaborations and incubations to look at gaseous losses.
Intensive lab processing of the soils for both total carbon and charcoal content revealed some interesting differences. Charcoal (a long-lived carbon sequestering material) showed surprising patterns in compound disturbance situations (Buma et al. 2013) and export patterns (gaseous and aquatic) appear similar in ongoing work. Generally, the charcoal is isolated via the KMD digestion, a weak nitric acid method that is well suited for forest soils in higher latitudes.
There is a lot more to carbon dynamics in multiple disturbance environments than just the first-order, what is left after the burn considerations. Changes in successional trajectories kicked off by the compound event can cause differential C accumulation. Charcoal itself can change microbial respiration rates. Charcoal also changes the albedo of the surface, influencing soil temperature and thus respiration. In the far north, permafrost changes become significant as well. To combine these complex dynamics into a coherent whole, a new NSF program is being initiated with collaborators from around the country to investigate landscape resilience, carbon dynamics, and build a new modeling system to better understand how boreal forests will respond to multiple fires in the future.
The project is a collaborative effort with Portland State University, the University of Alaska, the University of Idaho, and North Carolina State University.