Page 136 - GIS for Science, Volume 3 Preview

Analysis of forest connectivity after the Oregon fires
While fire plays critical roles in sustaining ecosystems, including many that benefit biodiversity, shifts in vegetation conditions post-fire can influence the connectivity of landscapes for species that avoid recently burned areas. These reductions in connectivity can hinder wildlife access to important habitat areas and limit gene flow among neighboring populations.
Similarly, the mosaic of vegetation conditions that arise after burning prevents seeds from surviving trees from reaching the interior of the burn scar, a condition that impedes forest regeneration. Connectivity modeling tools based on electrical circuit theory can provide insight into these potential changes in “ecological flows'' across landscapes as fires change the distributions of various land cover types.
By any measure, the 2020 western US wildfire season was one of the worst in recorded history. Even Portland, Oregon, normally associated with cool weather and summer rains, experienced unusually high winds and continued dry weather, which in turn caused many fires to spread quickly throughout the state. In Oregon, more than one million acres burned, leading to more than 40,000 evacuations and putting a half million people within evacuation warning areas. With so much land altered in one series of events, forest researchers relied on NASA data to evaluate the immediate impact on forest connectivity.
NASA’s Applied Sciences Program worked in conjunction with The Nature Conservancy to illustrate the potential influence of fires observed in 2020 on the connectivity of forests in the western United States. To begin, Visible Infrared Imaging Radiometer Suite (VIIRS) thermal hot spot data for August through October 2020 was combined with percentage of forest cover and land cover data from the National Land Cover Database (2016), both rescaled to 180-meter pixels.
Land cover in western Oregon overlayed with VIIRS thermal hot spot imagery. The black areas delineate the most recent burn scars from the 2020 fires.
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Smoke-filled skies over downtown Portland, Oregon, on September 9, 2020.