Ground-based monitoring for the vegetation composition and structure vital sign for the Southwest Alaska Network (SWAN), focuses on documenting trends in the structure, composition, and demography of selected late-successional vegetation classes in response to environmental changes across three elevation bands (0-450 m; >450-900 m; >900 m) within the three largest parks: Katmai (KATM), Kenai Fjords (KEFJ), and Lake Clark (LACL). SWAN employed a Generalized Random-Tesselation Stratified (GRTS) sampling design, which involved a two-stage sampling scheme to ensure safety and accessibility while establishing permanent plots in selected vegetation classes. In order to focus on long-term changes rather than successional dynamics, the monitoring targeted specific vegetation classes that are common, late-seral, and sensitive to environmental changes, while avoiding early-successional classes. The selected vegetation associations included low elevation interior spruce forests, mid-elevation white spruce woodlands, low and dwarf shrub communities, and alpine dwarf shrub-fellfield communities, reflecting a gradient from warm coastal to colder alpine environments. Selected monitoring plots were revisited at approximately 5 year intervals, during which point intercept, nested quadrat frequency, tree censuses, and other structural and environmental measurements were performed.

The dataset comprises vegetation cover and shrub occurrence along a point intercept survey in two 1 ha plots at the Great Western Woodlands site between 2013 - 2015

In support of mapping ecological conditions (e.g. invasive annual grass) in sagebrush-dominated landscapes of the western United States, we developed weekly (starting from week 7 to week 42 and Week 1 starts January 1 or Day of the year 1 to 7, week 2 is from Day of year 8 to 14, and so on) 30-m cloud-free Normalized Difference Vegetation Index (NDVI) from 2016 to 2019. The data was generated with machine-learning techniques (i.e., regression tree [RT]) and harmonized Landsat and Sentinel -2 (HLS) data. The geographic coverage includes areas in the Great Basin, the Snake River Plain, the state of Wyoming, and contiguous areas. This NDVI collection allows for local-scale detection and analysis such as, fuel breaks in sagebrush ecosystem and wildfire activity, that are not possible with coarse scale datasets (such as 250-m).

In support of mapping ecological conditions (e.g. invasive annual grass) in sagebrush-dominated landscapes of the western United States, we developed weekly (starting from week 7 to week 42 and Week 1 starts January 1 or Day of the year 1 to 7, week 2 is from Day of year 8 to 14, and so on) 30-m cloud-free Normalized Difference Vegetation Index (NDVI) from 2016 to 2019. The data was generated with machine-learning techniques (i.e., regression tree [RT]) and harmonized Landsat and Sentinel -2 (HLS) data. The geographic coverage includes areas in the Great Basin, the Snake River Plain, the state of Wyoming, and contiguous areas. This NDVI collection allows for local-scale detection and analysis such as, fuel breaks in sagebrush ecosystem and wildfire activity, that are not possible with coarse scale datasets (such as 250-m).

SWAN_Vegetation_Database.zip contains 24 .csv's comprising the main components of the SWAN Vegetation Monitoring Database. SWAN_Vegetation_Database_Fields.zip contains another 24 .csv's describing the columns present on the main components of the SWAN Vegetation Monitoring Database along with another 10 .csv's describing categorical type data, where present. 8/5/2025 update: Includes a minor fix on taxon code around "FEBR2" (which was resolving to a date reference on Veg_Taxon and ~20 instances where "FEBR2" was encountered in field. Includes change of name "TreeSeedling" table (and related metadata) to "TreeSapling". Includes inclusion of 10 new categorical type metadata tables along with a few minor related changes to attribute tables (changing a few columns auto-identified as a "categorical" type to "character" type). Includes "one-line" descriptions of each of the 24 data tables present in Table and Relationships section of reference publish. Includes minor changes to "Plot" table (addition of two columns, Qualifier_Code and GRTS_Number) along with related changes to corresponding "Plot" attribute metadata and categorical metadata tables to describe added columns. Qualifier_Code and GRTS_Number are part of the concatenation that forms the "Plot" column referenced on most of the other data columns. Of note, catvars_SWAN_Veg_Plot.txt includes descriptions of the Qualifier_Code column, for which the "S" on "Plot" is derived from, when present. Depending on the park where the plot is present and the Elevation_Band_Code the plot is connected to, this "S" can either refer to "Spruce" (identified as a spruce forest sample, at either Elevation_Band_Code 1 or 2) or "South" (south of Turquoise Lake at LACL at Elevation_Band_Code 3). For more information, please refer to catvars_SWAN_Veg_Plot.txt contained in this reference or reference: "Protocol for Ground-based Monitoring of Vegetation in the Southwest Alaska Network" (https://irma.nps.gov/DataStore/Reference/Profile/2097701).

24 data containing .csv's comprising the main components of the SWAN Vegetation Monitoring Database plus another 24 .csv's describing the columns present on the main components of the SWAN Vegetation Monitoring Database.

SWAN_Vegetation_Database.zip contains 24 .csv's comprising the main components of the SWAN Vegetation Monitoring Database. SWAN_Vegetation_Database_Fields.zip contains another 24 .csv's describing the columns present on the main components of the SWAN Vegetation Monitoring Database along with another 10 .csv's describing categorical type data, where present. 8/5/2025 update: Includes a minor fix on taxon code around "FEBR2" (which was resolving to a date reference on Veg_Taxon and ~20 instances where "FEBR2" was encountered in field. Includes change of name "TreeSeedling" table (and related metadata) to "TreeSapling". Includes inclusion of 10 new categorical type metadata tables along with a few minor related changes to attribute tables (changing a few columns auto-identified as a "categorical" type to "character" type). Includes "one-line" descriptions of each of the 24 data tables present in Table and Relationships section of reference publish. Includes minor changes to "Plot" table (addition of two columns, Qualifier_Code and GRTS_Number) along with related changes to corresponding "Plot" attribute metadata and categorical metadata tables to describe added columns. Qualifier_Code and GRTS_Number are part of the concatenation that forms the "Plot" column referenced on most of the other data columns. Of note, catvars_SWAN_Veg_Plot.txt includes descriptions of the Qualifier_Code column, for which the "S" on "Plot" is derived from, when present. Depending on the park where the plot is present and the Elevation_Band_Code the plot is connected to, this "S" can either refer to "Spruce" (identified as a spruce forest sample, at either Elevation_Band_Code 1 or 2) or "South" (south of Turquoise Lake at LACL at Elevation_Band_Code 3). For more information, please refer to catvars_SWAN_Veg_Plot.txt contained in this reference or reference: "Protocol for Ground-based Monitoring of Vegetation in the Southwest Alaska Network" (https://irma.nps.gov/DataStore/Reference/Profile/2097701).