Managing fire with fire in Alaskan black spruce forests: Impacts of fire severity on successional trajectory and future forest flammability So now that I have given you that background, my research questions are: In interior Alaska 2) And in particular soil carbon sequestration.

WHO ARE WE? Teresa Hollingsworth- Boreal Ecology Cooperative Research Unit,USDA Forest Service, PNW Research Station Terry Chapin- University of Alaska Jill Johnstone- University of Saskatewan Michelle Mack and Ted Schuur- University of Florida David Verbyla- University of Alaska Emily Bernhardt- UAF Leslie Boby- UFL Andy Ruth- NPS Katie Villano- UAF Julie Benioff Jamie Hollingsworth Emily Tissier

Background for study TNH work on black spruce communities (Hollingsworth et al. (2006) Can. J. For. Res. 36: 1781-96, Hollingsworth, Schuur et al. (in revision) Ecosystems) JJ work on tree successional trajectories (Johnstone & Chapin (2006) Ecosystems 9: 14-31, Johnstone & Kasischke (2005) Can. J. For. Res. 35: 2151-2163, Johnstone (2005) Can. J. For. Res. 35: 483-486) DV work on burn severity (Epting, J. and D. L. Verbyla. 2005. Canadian Journal of Forest Research. 35:1367-1377)

Background for study (cont.) Extensive area burned in Alaska in 2004 Alaska landscape dominated by flammable black spruce Wildland fire behavior is heavily dependent natural mosaic of land cover types Future landscape flammability will be driven by patterns of forest recovery => What is the potential for black spruce sites to regenerate to less flammable, deciduous forests? => Can regeneration trajectories be predictably linked to fire severity, pre-fire vegetation, and site moisture?

Picea mariana (black spruce) communities Black spruce exhibits large phenotypic plasticity Exists in a large range of environmental conditions Black spruce is fire-adapted Predominant tree type in interior Alaska In addition to its large range

What are the relationships between pre-fire stand structure and composition and post-fire successional trajectory?

Study design 90 sites established in 2004 burns along Dalton, Taylor, and Steese Highways 32 intensive study sites arranged across combinations of high-low site moisture & high-low burn severity 7 treeline sites Detailed pre-fire stand data available for 14 sites Reconstruction of pre-fire conditions at remaining sites

Severity: Moisture: Low High Dry Wet Example of our classification scheme for sites. Severity is the amount of physical change in an ecosystem caused by burning. Severity classification was a visual score of % canopy consumed and depth of burning of forest floor—rough, fast, analagous to the types of assesments that land managers make Moisture was classified by vegetation-drainage relationships developed in unburned stands. Wet