Lead Authors:
Edward A. G. Schuur, Northern Arizona University
A. David McGuire, U.S. Geological Survey and University of Alaska, Fairbanks
Vladimir Romanovsky, University of Alaska, Fairbanks
Contributing Authors:
Christina Schädel, Northern Arizona University
Michelle Mack, Northern Arizona University
Science Lead:
Sasha C. Reed, U.S. Geological Survey
Review Editor:
Marc G. Kramer, Washington State University, Vancouver
Federal Liaisons:
Zhiliang Zhu, U.S. Geological Survey
Eric Kasischke (former), NASA
Jared DeForest (former), DOE Office of Science

Arctic and Boreal Carbon

Forestry is the most widespread human management activity that affects the carbon cycle in the most productive and accessible portion of the boreal forest. This section focuses on a case study of how wildfire management in Alaska has the potential to affect the fire cycle and, consequently, carbon pools via pathways described earlier in the chapter. In Alaska, all lands are classified into fire management planning options depending on the proximity to and density of human infrastructure. The range of management options include “Limited” (i.e., the least amount of management where fire activity is largely observed but not suppressed), “Modified,” “Full,” and “Critical” (i.e., assigned to lands immediately surrounding human settlements and key infrastructure and resources). Each option represents an increasing amount of human intervention to suppress wildfire activity. This case study describes a modeling experiment conducted to determine the impact of changing fire management planning options from the current designation of Limited or Modified to Full protection for all military lands in the greater Fairbanks, Alaska, area. This change in fire management led to a small increase in the projected number of fires per decade because more flammable vegetation (e.g., late successional conifer forests) would be preserved, but, importantly, there was a projected decrease in the cumulative area burned through 2100 compared to the status quo (see Figure 11.8). Depending on the particular climate projection, active fire management (Full) decreased the projected cumulative area burned by 1.5% to 4.4% by 2100 (Breen et al., 2016). Differences in projected climate by 2100 arising from different climate model formulations have a strong impact on cumulative area burned, but fire management does have a small effect no matter the actual climate realized at the end of the century. In the absence of changing fire severity, the effect on carbon emissions would be exactly proportional to the difference in area burned. However, the somewhat small difference in cumulative area burned, and the proportional resulting effect on the carbon cycle, would need to be considered in context with the additional resources required to change the fire management planning option from the lower to higher level.


Figure 11.8: Effects of Two Climate Scenarios and Two Management Scenarios for a Subregion of Alaska

Figure 11.8: Cumulative area burned is modeled for the historical (1950 to 2009) and projected (2010 to 2100) periods for the Upper Tanana Hydrological Basin in interior Alaska near Fairbanks. Model results are presented for scenarios of fire management plan options (FMPO) driven by two Earth System Models: Meteorological Research Institute Coupled Global Climate Model version 3 (MRI-CGCM3) and National Center for Atmospheric Research Community Climate System Model version 4 (NCAR-CCSM4) using the Representative Concentration Pathway (RCP) 8.5 “business-as-usual” emissions scenario. Data presented are means, and shading indicates results from 200 model replicates; black dashed line is the actual fire record through 2010. [Figure source: Redrawn from Breen et al., 2016; Schuur et al., 2016, used with permission.]