Previous photo pair1951 - 2004: Toklat Basin Lowlands near Toklat Basin4/9Next photo pair
Toklat photo pair
Photo Credits: Technical aerial photo (USGS) (1951), Technical aerial photo (USGS) (2004)
Ecoregion: Alaska Range Mountains
Change Type: Permafrost dynamics
Permafrost dynamicsAnimation is available
These two aerial photos were taken 53 years apart, and show changes that have occurred in riparian areas of streams flowing through terrain that is heavily influenced by continuous permafrost. The low, smooth-appearing vegetation (reddish in the recent photo) is sedge-tussock tundra and low ericaceous-dwarf birch in terrain with a very shallow active layer. The taller (dark green) vegetation occupies thawed terrain along flowing water that tends to transfer heat and thaw permafrost in stream-course areas. Note the migration of larger-statured vegetation towards the top of the frame in areas that were open floodplain deposits in 1951, and supported tall shrubs and trees in 2004. What other changes can you detect between the two images?