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Multi-scale modeling of boreal forest vegetation growth under the influence of permafrost and wildfire interactions

Adrianna Foster, NASA GSFC / USRA, adrianna.c.foster@nasa.gov (Presenter)
Amanda HIldt Armstrong, University of Virginia, amanda.h.armstrong@nasa.gov
Jacquelyn K. Shuman, National Center for Atmospheric Research, jkshuman@ucar.edu
Kenneth Jon Ranson, NASA GSFC, kenneth.j.ranson@nasa.gov
Herman Henry Shugart, University of Virginia, hhs@virginia.edu
Brendan Morris Rogers, Woods Hole Research Center, brogers@whrc.org
Scott J. Goetz, Northern Arizona University, scott.goetz@nau.edu

Global temperatures have increased about 0.2°C per decade since 1979, and the high latitudes are warming faster than the rest of the globe. Climate change within Alaska is likely to bring about increased drought and longer fire seasons, as well as increases in the severity and frequency of fires. These changes in disturbance regimes and their associated effects on ecosystem C stocks, including permafrost, may lead to a positive feedback to further climate warming. As of now, it is uncertain how vegetation will respond to ongoing climate change, and the addition of disturbance effects leads to even more complicated and varied scenarios. Through ecological modeling, we have the capacity to examine forest processes at multiple temporal and spatial scales, allowing for the testing of complex interactions between vegetation, climate, and disturbances. The University of Virginia Forest Model Enhanced (UVAFME) is an individual tree-based forest model that has been updated for use in interior boreal Alaska, with a new permafrost model and updated fire simulation. These updated submodels allow for feedback between soils, vegetation, and fire severity through fuels tracking and impact of depth of burn on permafrost dynamics. We present these updated submodels as well as calibration and validation of UVAFME to the Yukon River Basin in Alaska, with comparisons to inventory data. We also present initial findings from simulations of potential future forest biomass, structure, and species composition across the Yukon River Basin under expected changes in precipitation, temperature, and disturbances. We predict changing climate and the associated impacts on wildfire and permafrost dynamics will result in shifts in biomass and species composition across the region, with potential for further feedback to the climate-vegetation-disturbance system. These simulations advance our understanding of the possible futures for the Alaskan boreal forest, which is a valuable part of the global carbon budget.

Associated Project(s): 

Poster Location ID: 81

Session Assigned: Vegetation Dynamics and Distribution

 


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