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permafrost photo pair
Photo Credits: Fred Dean (1976), NPS (2005)
Ecoregion: Yukon-Kuskokwim Bottomlands
Change Type: Changing treelines
Changing treelinesAnimation is available
This photo pair shows a good example of the influence of running water on permafrost and plant growth in the subarctic. The dark band is a stream corridor densely packed with trees, which stands in stark relief with the majority of the area shown in these frames, which is terrain dominated by relatively shallow permafrost. The warmth of flowing water causes the thaw band along the stream, which allows trees to grow larger and taller. The cold, wet, and acidic soils in the permafrost areas support slower plant growth and less productive vegetation communities. One change between the two photos of this site is the continued growth of the trees shown, which not surprisingly, are larger in the 2005. In addition, the boradleaved species (poplar and birch) which have a light green appearance appear to be relatively more abundant in the later photo as compared to the spruce.