Managing fire with fire in Alaskan black spruce forests: Impacts of fire severity on successional trajectory and future forest flammability
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
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: High Low Dry Moisture: Wet