NOTE: this version, V2B, has been REPLACED by reference 2294375: https://irma.nps.gov/DataStore/Reference/Profile/2294375. The 2294375 replacement was derived using newer methods where outputs were generated using Google Earth Engine (GEE) instead of IDL and following a newer protocol: Protocol for Landsat-based monitoring of landscape change in North Coast and Cascades Network parks: Version 2.1, reference code 2294109.

Landsat/LandTrendr derived landscape change data from Olympic National Park and surrounding study area, labeled by landscape change type chosen from a discrete list. This data set is an updated version (V2B) of the data set summarized in the following report: Landsat-based Monitoring of Landscape Dynamics in Olympic National Park: 1985-2010. Natural Resource Data Series NPS/NCCN/NRDS—2016/1053. The updates include the addition of Confidence and Alt_type fields and additional office validation and labeling of patches inside the park boundary and surrounding USFS Wilderness Areas. This data set is considered superior to the V2A data set that was used for report summaries.

As part of Vital Signs Monitoring, the North Coast and Cascades Network (NCCN) of the National Park Service (NPS) developed a protocol for monitoring landscape change using Landsat satellite imagery. The protocol was implemented at Olympic National Park (OLYM) in 2014 using LandTrendr (Landsat-based Detection of Trends in Disturbance and Recovery) algorithms developed by Oregon State University.

LandTrendr tracks the spectral trajectory of Landsat pixels through time and smoothes their spectral index signatures into coherent segments describing periods of stability or change. The primary outputs from LandTrendr are the year of change onset, the duration of change, and the magnitude of the change. Adjacent pixels with the same year of change onset are then grouped into patches. Only changes larger than 0.8 ha (2 ac) and for which the duration of the period of landscape change is less than or equal to 4 years are retained.

Nine categories of landscape change were mapped: Avalanches, Clearing, Development, Fire, Mass Movements, Progressive Defoliation, Riparian, Tree Topplings, and Winter Ice. The Avalanche category captures long, linear change which partially or completely removes vegetation from the valley wall following a release of a large mass of snow down a mountain side. Clearings are areas under forest management where practices vary from thinning to clearcuts. The Development category captures changes associated with complete and persistent removal of vegetation and transformation to a built landscape. Changes due to Fire vary in intensity from full canopy removal to partial burns that leave behind a mixture of dead and singed trees. The Mass Movement category includes both landslides found on valley walls and debris flows associated with streams. Progressive Defoliation is a change type in which the forest cover remains but has declined due to insect infestation, disease or drought. Riparian changes are restricted to the valley floors alongside major streams and rivers and capture areas where either conifer or broadleaf vegetation previously existed and has been converted to river channel. Change due to Tree Toppling is evidenced by broken or topped trees, generally due to wind but sometimes to root rot. Winter Ice category captures changes in vegetation damaged by heavy, long lasting snow and ice followed by sever winds; generally characterized by broken tree branches. These data were summarized in Copass, C., N. Antonova, and S. Clary. 2016. Landsat-based monitoring of landscape dynamics in Olympic National Park: 1985-2010. Natural Resource Data Series. NPS/NCCN/NRDS—2016/1053. National Park Service. Fort Collins, Colorado (https://irma.nps.gov/DataStore/Reference/Profile/2233073).