Existing Vegetation Layer Description Mid Level

Revised National and Region 5 Standards

Existing vegetation GIS maps are comprehensive vegetation databases that meets regional and national vegetation mapping standards. A mapping methodology has been developed to capture forest vegetation characteristics using automated, systematic procedures, remote sensing classification, photo editing and field based observations that efficiently and cost-effectively map large areas with minimal bias. Map attributes consist of land use Anderson 1, life form cover type, FGDC physiognomic order, class and subclass, vegetation types using the CALVEG classification system and forest structural characteristics. Forest productivity is determined by CALVEG type. Integration of other data sources for water features and re-forestation origin dates are implemented where available. More info.

The CALVEG classification is a provisional system that meets the floristically based level of the National Vegetation Classification Standard hierarchy. These vegetation alliances were originally developed by the Region's Ecology Program in 1978. (USDA Forest Service. 1981. CALVEG: A Classification of California Vegetation. Pacific Southwest Region, Regional Ecology Group, San Francisco CA. 168 pp.) The descriptions and keys are being maintained and updated by the Pacific Southwest Region. The system currently consists of 178 distinct vegetation and land use types. More info.



The following are the general mapping and classification rules for the existing vegetation layer.



Vegetation Mapping Criteria:

  • Minimum Mapping Size
    • 2.5 acres for contrasting vegetation conditions based on cover type, vegetation type, tree cover from above classes and overstory tree diameter classes
    • No minimum mapping unit for lakes and conifer plantations
  • Life Forms are initially generated from classification of Landsat Thematic Mapper imagery into the following hierarchical classes:
    • Conifer - greater than 10 percent conifer cover as the dominant type
    • Mix - greater than 10 percent tree cover and 20 to 90 percent hardwood cover
    • Hardwood - greater than 10 percent hardwood cover as the dominant type
    • Shrub - greater than 10 percent shrub cover as the dominant type
    • Grass - greater than 10 percent grass cover as the dominant type
    • Barren - less than 10 percent cover of any natural vegetation
    • Agriculture
    • Urban
    • Ice/snow
    • Water
  • Subsequently, the following items are mapped within Life Form classes:
    • Vegetation Dominance Type (CALVEG): Rules have been developed by Vegetation Zone for setting parameters for CALVEG mapping. Complete Calveg mapping keys and detailed alliance descriptions.
    • Physiognomic Division, Order and Class as well as SAF and SRM types are derived from a crosswalk from cover type and CALVEG type. Total tree cover is also used for deriving Physiognomic Subclass along with cover type and CALVEG type.
    • Tree Cover from Above: Conifer and hardwood tree cover is mapped as a function of canopy closure in ten- percent classes. In conifer/hardwood mixtures, relative density of each is mapped as well as total tree canopy closure, with conifer tree cover stored in item CON CFA, hardwood tree cover stored in HDW CFA and total tree cover mid level class stored in Tree CFA 1.
    • Overstory Tree Diameter: Overstory tree sizes are mapped as a function of crown diameters of overstory trees as interpreted from aerial photography and satellite imagery. Conifer seedling and sapling sizes are modeled based on planting origin dates where available from agency records. Fire history and change detection are also inputs to determine small tree sizes when not directly observable on image sources. The plurality size condition of the predominant, dominant, and co-dominant trees in a stand is assigned and stored in OS Tree Diameter Class 1. For Mixed tree types, conifer size in stored in OS Tree Diameter Class 1, and hardwood size is stored in OS Tree Diameter Class 2.

Additional Fields:

  • Ecological Tile: The basic units used to store existing vegetation layers within a statewide existing vegetation library. Source is from Goudey and Smith (1994), Ecological Units of California-Subsections (map), USDA Forest Service, Pacific Southwest Region, San Francisco, CA. Scale 1:1,000,000. Calveg Zone, Ecological Domain, Division, Province, Section and Subsection lines are retained from this source.
  • WHR Type, Size, Density, and Range: Corresponding parameters from the California Wildlife Habitat Relationships classification system. WHR type is derived primarily from CALVEG type and relative cover of conifer and hardwood trees for various mixed conditions. WHR tree size class is a mapped attribute. WHR tree density is calculated from conifer and hardwood cover from the above values. More info.
  • Northwest Structure: Structural attributes specific to monitoring requirements for the Northwest Forest Plan and not present in Forest vegetation layers outside the Klamath Province.
  • Feature level metadata is captured for mapping sources, source dates and update causes.
  • Map Tile: A tiling system currently being used to tile the existing vegetation dataset and to serve out logical portions of vegetation data for use in land management issues such as forest-wide planning efforts, wildlife habitat mapping and fire risk assessment.



Key to row colors:



National Standards Green
Region 5 Add Ons Yellow


Field Description Field Name Column Width Type Valid Codes
Domains of the United States ECOREGION_ DOMAIN 4 TEXT Table 101
Divisions of the United States ECOREGION_ DIVISION 3 TEXT Table 102
Provinces of the United States ECOREGION_ PROVINCE 4 TEXT Table 103a
Sections of the United States ECOREGION_ SECTION 5 TEXT Table 104a
Subsections of the United States ECOREGION_ SUBSECTION 6 TEXT Table 105a
USGS Land Use / Land Cover USGS_ANDERSON_1 1 TEXT Table 199
USGS Land Use / Land Cover, Level 2 USGS_ANDERSON_2 2 TEXT Table 182
National Vegetation Classification System (NVCS) Division PHYSIOGNOMIC_ DIVISION 1 TEXT Table 198
SAF Cover Type SAF_COVER_TYPE 3 TEXT Table 60c
SRM Rangeland Cover Types SRM_COVER_TYPE 3 TEXT Table 200
Aggregation Type AGGREGATION_ TYPE 1 TEXT Table 201
Regional Dominance Type 1 REGIONAL_ DOMINANCE _TYPE_1 3 TEXT Table 38
Tree Cover From Above Class 1 TREE_CFA_CLASS_1 2 TEXT Table 194
Overstory Tree Diameter Class 1 OS_TREE_DIAMETER _CLASS_1 2 TEXT Table 202
Regional Dominance Type 2 REGIONAL_ DOMINANCE _TYPE_2 3 TEXT Table 38
Overstory Tree Diameter Class 2 OS_TREE_DIAMETER _CLASS_2 2 TEXT Table 202
Regional Dominance Type 3 REGIONAL_ DOMINANCE _TYPE_3 3 TEXT Table 38
National code for data source DATA_SOURCE 5 TEXT Table 218
Date imagery was captured SOURCE_DATE 8 DATE MM/DD/YYYY
Update Cause MAP_UPDATE_CAUSE 2 TEXT Table 164C
Date of feature creation or latest update REV_DATE 8 DATE MM/DD/YYYY
Map Tile ID TILE 3 TEXT 01 - 72
Vegetation Cover Type COVERTYPE 3 TEXT Table 37
Conifer Cover From Above CON_CFA 2 TEXT Table 203
Hardwood Cover From Above HDW_CFA 2 TEXT Table 203
Shrub Cover From Above SHB_CFA 2 TEXT Table 203
Herbaceous Cover From Above HEB_CFA 2 TEXT Table 203
Total Tree Cover From Above - 10 percent classes TOTAL_TREE_CFA 2 TEXT Table 203
Canopy Structure CANOPYSTRUCTURE 2 TEXT Table 165
Timberland Productivity PROD 1 TEXT Table 43
Reforestation Status REFORESTATION_ STATUS 2 TEXT Table 42a
WHR Lifeform WHRLIFEFORM 7 TEXT Table 114D
WHR Type WHRTYPE 3 TEXT Table 114A
WHR Size WHRSIZE 2 TEXT Table 114B
WHR Density WHRDENSITY 1 TEXT Table 114C
Region 5 code for data source R05_DATA_SOURCE 5 TEXT Table 118
Date attributed to change CAUSE_DATE 8 DATE MM/DD/YYYY