Vulnerability and resiliency of Alaskan black spruce forests to increased fire activity during the 2001 to 2010 time period

Eric S. Kasischke, University of Maryland, ekasisch@umd.edu (Presenter)
Merritt R. Turetsky, Michigan State University, mrt@uoguelph.ca
Kirsten Barrett, USGS, kbarrett@usgs.gov
Evan S Kane, USFS Northern Research Station, eskane@mtu.edu
Elizabeth E Hoy, University of Maryland, elizabeth.hoy@nasa.gov
Tatiana Loboda, Univ. Maryland, loboda@umd.edu
Shenoy Aditi, Univ. of Alaska, aditi.shenoy@gmail.com

Recent studies have shown that fires that burn deeply into surface organic layers in mature black spruce forests create conditions that foster the recruitment and growth of deciduous tree seedlings, leading to the potential of a post-fire shift in tree dominance from spruce to aspen or birch. Based on this observation and the increase in burned area that has occurred in Alaska’s boreal forest region has resulted in modeling studies that are predicting a rapid shift in forest cover beginning in the early 1990s and continuing for 50 years. Here, we present results of a recent study where we examined the average depth of burning from some 240 sites located throughout interior Alaska to determine the frequency of average post-fire organic layer depths as a function of topographic position and fire conditions (early vs. late season fires, small vs. large fire years). We measured the amount of mature spruce forest that burned during the 2000s using satellite data products combined with a DEM to determine topographic position. The results from this study show that only 4 to 8 percent of the mature black spruce forest that existed prior to 2000 burned deep enough to support a shift to a deciduous dominated forest stand. We observed that certain topographic positions were resistant to deep burning, providing black spruce forests a high degree of resiliency in the face of recent increases in fire activity. These results show that black spruce forests are less vulnerable to the impacts of recent changes to the fire regime than modeling studies indicate.

Presentation Type:  Poster

Session:  Poster Session 2-A   (Wed 11:00 AM)

Associated Project(s): 

• Assessing the impacts of fire and insect disturbance on the terrestrial carbon budgets of forested areas in Canada, Alaska, and the Western United States
• Remote Monitoring of Changes in Forest Functional Types after Disturbance from Fire in the North American Boreal Region: Implications for Interpreting the Effects of Satellite-observed Changes in Vegetation Greenness on the Terrestrial Carbon Budget

Poster Location ID: 53