Life Histories from Landsat: 25 Years in the Pacific Northwest Forest

This visualization shows a sequence of Landsat-based data in the Pacific Northwest. There is one data set for each year representing an aggregate of the approximate peak of the growing season (around August). The data was created using a sophisticated algorithm called LandTrendr. LandTrendr analyzes 'stacks' of Landsat scenes, looking for statistical trends in the data and filtering out noise. The algorithm evaluated data from more than 1,800 Landsat Thematic Mapper images, nearly 1 Terabyte of raw imagery, to define the life histories of each of more than 336 million pixels on the landscape. The resulting trends identify periods of stability and change that are displayed as colors.

In these false color images, the colors represent types of land; for example, blue areas are forests; orange/yellow areas are agriculture; and, purple areas are urban. Each 'stack' is representative of a Landsat scene. There are 22 stacks stitched together to cover most of the U.S. Pacific Northwest. This processed data is used for science, natural resource management, and education.

The visualization zooms into the Portland area showing different types of land such as agricultural, urban, and forests. We move south to a region that was evergreen forest for a number of years (blue), then was clear cut in 1999 (orange), then began to regrow (yellow). A graph shows the trajectories for a particular location in the clearcut as the years repeat. The dots represent the original data from Landsat; and, the line represents LandTrendr analysis. We move over to the Three Sisters region to show an area of pine forest that becomes infested with bark beetles in 2004. Next, we move to the southern foothills of Mount Hood where a budworm infestation is in progress; around 1991, the worms move on to another area and shrubs start to regrow. Next we

move to the east side of Mount Rainier National Park to see another budworm outbreak followed by shrub regrowth. Finally, we move to the west of Mount Rainier where we can see widespread clear cutting outside of the park, but no clear cutting inside the protected park land.

Don't miss this related tour of the region.