NCCN Landscape Dynamics Monitoring LEWI geospatial data 1985-2011

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 Lewis and Clark National Historical Park (LEWI) in 2016 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.

This data set contains 1985-2011 Landsat/LandTrendr derived landscape change data from Lewis and Clark National Historical Park, and surrounding areas, labeled by landscape change type chosen from a discrete list. Nine categories of landscape change that occurred at LEWI and surrounding areas from 1985 to 2011 were mapped: Agricultural Clearing, Clearing, Coastal, Development, Mass Movements, Progressive Defoliation, Tree Topplings, Wetland Restoration, and Windthrow Salvage. The Agricultural Clearing category includes first-time removal of vegetation for agricultural activities. Clearings are areas under forest management where practices vary from thinning to clearcuts. Coastal category captures partial to complete vegetation removal due to storm surges or other factors unique to coastal foredune and stand. The Development category captures changes associated with complete and persistent removal of vegetation and transformation to a built landscape. 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. Change due to Tree Toppling is evidenced by broken or topped trees, generally due to wind but sometimes to root rot. Wetland restoration category covers cleared areas that show change due to active restoration projects inside the park boundary. Windthrow Salvage is a unique category that captures areas affected by the 2007 Great Coastal Gale where the windthrown trees were subsequently salvaged and therefore now show a similar spectral signature as Clearing. Each patch was assigned a subjective level of "confidence" in the choice of landscape change type label ranging from one (least confident) to three (most confident). An alternative change type was given when the confidence of one or two was chosen and when the patch was mixed, i.e. contained two types of change. These data were summarized in the National Park Service Natural Resource Data Series Report (https://irma.nps.gov/DataStore/Reference/Profile/2259286).