The lightning data is fairly similar to the thunderstorm climatology map that NOAA produced in their 1976 report on thunderstorm climatology in Alaska. Their report showed the greatest density in the Fortymile Country whereas the BLM's lightning data indicates the area immediately east of Fairbanks has the highest density of lightning strikes.
Figure 2. Smoothed number of lightning strikes per square mile in Alaska (1986-2012). Grid cells are 10 square miles and the data were smoothed using a 3x3 mean filter.
Figure 3. Figure 7 from 1976 NOAA report on thunderstorm climatology in Alaska.