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Larger

All

Small

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1950-1984

1985-2006

Figure 13.7 Seasonal patterns of burned area for two periods for small and larger fire years in Alaska (see also Plate 21 for color version)

Source: Based on fire records from the Alaska Fire Service, Bureau of Land Management.

Trends in surface temperatures of shallower soil layers in permafrost regions are more variable because inter-annual differences in snow depth and winter-time temperature can cause large variations in near surface temperatures. However, for the period from 1960 to 1999, model studies calculate an overall rise of about 2°C for near surface mineral soil temperatures in black spruce forests with permafrost (Hinzman et al, 2006), which matches the difference in annual average temperature between the north- and south-slope sites shown in Figure 13.1.

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