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Updated March 13, 2023
  VIDEO: Overview

  VIDEO: Using the map cursor

Interface | Streams | Region | Grid | Climate | Soil | Ultramafic | Geology | Release Notes

One Polygon Layer at a Time
Layers are available in several Calflora applications that use Google Maps, including Observation Search. The map applications can show one polygon background layer at a time. When a background polygon layer is selected, and you click on the map inside of a polygon, you will see the name of the polygon below the map.

County Lines and Streams can be turned on at the same time as a polygon background layer. These two layers are lines, not polygons, and so can be superimposed on top of the selected polygon layer.

Map Cursor
See the Introduction to Calflora Map Applications, which explains how the map cursor works.

Polygon Background Layers
Polygon background layers are divided into four groups: Region, Grid, Climate, and Soil. Click on a group name -- for instance Region -- to see all of the layers within that group. Then click on the name of a layer -- for instance Protected Areas (CPAD) -- and the colored polygons of that layer will be superimposed on top of the Google Map. Note that not all layers are available at all zoom levels.

The four checkboxes at the bottom control the appearance of colored polygons in the selected background layer. If the appearance of the polygons is too subtle, you can emphasize the outline of each polygon, or ask for a darker background color for each polygon.

Here is an example of the Climate / Precipitation layer with darker background colors and a thick white outline (click to see it "live").

Click on Streams to see rivers and creeks on the map. If you are zoomed way out, you will only see the longest rivers. As you zoom in, the shorter streams appear.

When you check Stream names, a stream icon will appear at the end of each creek or river. When you click on the icon, you see the name of the creek or river, and the name of the stream that the creek or river flows into.

For instance, in Monterey County, the icon for the creek called Arroyo Seco appears at the end of the Arroyo Seco, where it flows into the Salinas River. When you click on the icon an info window pops up describing the junction:
Arroyo Seco / Salinas River
The course of the stream itself -- the Arroyo Seco -- is highlighted in blue. The course of the downstream creek or river -- the Salinas River -- is highlighted in green.

Uncheck Stream names to clear the map of all stream icons and all stream course highlighting.

If you move to a different location on the map or change zoom level, and would like to see stream name icons at the new location, press the refresh button .

The Streams dataset is from the May 27, 2019 version of the California Department of Fish and Wildlife California Streams dataset.

National Hydrography Dataset (NHD) high resolution NHDFlowline features for California were originally dissolved on common GNIS_ID or StreamLevel attributes and routed from mouth to headwater in meters. The results are measured polyline features representing entire streams.

The named streams from the California Streams dataset are shown in Calflora map applications. If a named stream flows into an unnamed stream, that unnamed stream is also shown, with a label like "uns123". Many of these unnamed streams are canals or other engineered hydrologic features.


If this background polygon layer is selected, you will see county boundary lines (the same as County Lines above) for California counties. The county polygons themselves are not colored. However, when you click on the map inside of California, you will see the county name below the map.

California Protected Areas Database (CPAD)

Version 2018a (December, 2018) from Greeninfo Network

The California Protected Areas Database (CPAD) is a GIS inventory of all protected park and open space lands in California. The database contains lands held in fee ownership by public agencies and non-profits.

The units level of this database is shown in Calflora map applications. Click in an area to see its name.

For areas with restricted access or no access to the public, the warning is included after the name. For instance

San Francisco Watershed Lands - restricted access
  No Access
  Restricted Access
  Park or Open Space area; Public Access
  Federal Land (other than National Parks); Public Access

From CalWater 2.2.1.

Downloadable from San Jose State University Marine Pollution Studies Laboratory.

Calflora map applications can show the four levels of this dataset listed on the right. Which level is shown depends on how far in the map is zoomed in.

Level Example
Planning Watershed 3309.811105 Little Burnett Creek
Super Planning Watershed 3309.8111 McLaughlin Canyon
Hydrologic Area 3309.8 Paso Robles
Hydrologic Unit 3309. Salinas

Major Land Resource Areas (NRCS)

  04B Coastal Redwood Belt
  05 Siskiyou - Trinity Area
  14 Central California Coastal Valleys
  15 Central California Coastal Range
  16 California Delta
  17 Sacramento and San Joaquin Valleys
  18 Sierra Nevada Foothills
  19 Southern California Coastal Plains and Mountains
  21 Klamath and Shasta Valleys and Basins
  22A Sierra Nevada Mountains
  22B Southern Cascade Mountains
  23 Malheur High Plateau
  26 Carson Basin and Mountains
  29 Southern Nevada Basin and Range
  30 Mojave Desert
  40 Sonoran Basin and Range

4ETa Zones (description)
indicating evaopotranspiration (NRCS California)

  b18 - 21inches
  c15 - 18inches
  d12 - 15inches
  e9 - 12inches
  f6 - 9inches
  g3 - 6inches
  h0 - 3inches

EPA Ecoregions

Level III Ecoregions (documentation)
1. Coast Range
78. Klamath Mountains/California High North Coast
4. Cascades
9. Eastern Cascades Slopes and Foothills
80. Northern Basin and Range
6. Central California Foothills and Coastal Mountains
7. Central California Valley
5. Sierra Nevada
13. Central Basin and Range
8. Southern California Mountains
14. Mojave Basin and Range
85. Southern California Coast
81. Sonoran Basin and Range

Level IV Ecoregions (documentation)
1. Coast Range
1a. Coastal Lowlands
1i. Northern Franciscan Redwood Forest
1j. King Range/Mattole Basin
1k. Coastal Franciscan Redwood Forest
1l. Fort Bragg/Fort Ross Terraces
1m. Point Reyes/Farallon Islands
1n. Santa Cruz Mountains
1o. San Mateo Coastal Hills
78. Klamath Mountains/California High North Coast
78a. Rogue/Illinois/Scott Valleys
78d. Serpentine Siskiyous
78e. Inland Siskiyous
78g. Klamath River Ridges
78h. Border High-Siskiyous
78i. Western Klamath Low Elevation Forests
78j. Western Klamath Montane Forests
78k. Eastern Klamath Low Elevation Forests
78l. Eastern Klamath Montane Forests
78m. Marble/Salmon Mountains-Trinity Alps
78n. Scott Mountains
78o. Klamath Subalpine
78p. Duzel Rock
78q. Outer North Coast Ranges
78r. High North Coast Ranges
4. Cascades
4d. Cascade Subalpine/Alpine
4e. High Southern Cascades Montane Forest
4f. Low Southern Cascades Mixed Conifer Forest
4g. California Cascades Eastside Conifer Forest
4h. Southern Cascades Foothills
9. Eastern Cascades Slopes and Foothills
9g. Klamath/Goose Lake Basins
9h. Fremont Pine/Fir Forest
9i. Southern Cascades Slope
9j. Klamath Juniper Woodland/Devils Garden
9k. Shasta Valley
9l. Pit River Valleys
9m. Warner Mountains
9n. High Elevation Warner Mountains
9o. Likely Tableland
9p. Modoc/Lassen Juniper-Shrub Hills and Mountains
9q. Adin/Horsehead Mountains Forest and Woodland
9r. Adin/Dixie Low Hills
9s. Modoc Lava Flows and Buttes
9t. Old Cascades
80. Northern Basin and Range
80d. Pluvial Lake Basins
80g. High Lava Plains
80j. Semiarid Uplands
6. Central California Foothills and Coastal Mountains
6a. Tuscan Flows
6b. Northern Sierran Foothills
6c. Southern Sierran Foothills
6d. Camanche Terraces
6e. Tehama Terraces
6f. Foothill Ridges and Valleys
6g. North Coast Range Eastern Slopes
6h. Western Valley Foothills/Dunnigan Hills
6i. Clear Lake Hills and Valleys
6j. Mayacmas Mountains
6k. Napa-Sonoma-Lake Volcanic Highlands
6l. Napa-Sonoma-Russian River Valleys
6m. Sonoma-Mendocino Mixed Forest
6n. Bodega Coastal Hills
6o. Marin Hills
6p. Bay Flats
6q. Suisun Terraces and Low Hills
6r. East Bay Hills/Western Diablo Range
6s. San Francisco Peninsula
6t. Bay Terraces/Lower Santa Clara Valley
6u. Livermore Hills and Valleys
6v. Upper Santa Clara Valley
6w. Monterey Bay Plains and Terraces
6x. Leeward Hills/Western Diablo Range
6y. Gabilan Range
6z. Diablo Range
6aa. Eastern Hills
6ab. Pleasant Valley/Kettleman Plain
6ac. Temblor Range/Elk Hills
6ad. Grapevine Transition
6ae. Tehachapi Foothills
6af. Salinas Valley
6ag. Northern Santa Lucia Range
6ah. Santa Lucia Coastal Forest and Woodland
6ai. Interior Santa Lucia Range
6aj. Southern Santa Lucia Range
6ak. Paso Robles Hills and Valleys
6al. Salinas-Cholame Hills
6am. Cuyama Valley
6an. Carrizo Plain
6ao. Caliente Range
6ap. Solomon-Purisima-Santa Ynez Hills
6aq. Santa Maria/Santa Ynez Valleys
6ar. Upper Sacramento River Alluvium
7. Central California Valley
7a. Northern Terraces
7b. North Valley Alluvium
7c. Butte Sink/Sutter and Colusa Basins
7d. Southern Hardpan Terraces
7e. Sacramento/Feather Riverine Alluvium
7f. Sutter Buttes
7g. Yolo Alluvial Fans
7h. Yolo/American Basin
7j. Delta
7k. Lodi Alluvium
7l. Stockton Basin
7m. San Joaquin Basin
7n. Manteca/Merced Alluvium
7o. Westside Alluvial Fans and Terraces
7p. Granitic Alluvial Fans and Terraces
7q. Panoche and Cantua Fans and Basins
7r. Tulare Basin/Fresno Slough
7s. Kern Terraces
7t. South Valley Alluvium
7u. Antelope Plain
7v. Southern Clayey Basins
5. Sierra Nevada
5a. Sierran Alpine
5b. Northern Sierra Subalpine Forests
5c. Northern Sierra Upper Montane Forests
5d. Northern Sierra Mid-Montane Forests
5e. Northern Sierra Lower Montane Forests
5f. Northeastern Sierra Mixed Conifer-Pine Forests
5g. Central Sierra Mid-Montane Forests
5h. Central Sierra Lower Montane Forests
5i. Eastern Sierra Great Basin Slopes
5j. Eastern Sierra Mojavean Slopes
5k. Southern Sierra Subalpine Forests
5l. Southern Sierra Upper Montane Forests
5m. Southern Sierra Mid-Montane Forests
5n. Southern Sierra Lower Montane Forest and Woodland
5o. Tehachapi Mountains
13. Central Basin and Range
13h. Lahontan and Tonopah Playas
13u. Tonopah Basin
13v. Tonopah Sagebrush Foothills
13x. Sierra Nevada-Influenced Ranges
13y. Sierra Nevada-Influenced High Elevation Mountains
13aa. Sierra Nevada-Influenced Semiarid Hills and Basins
13ab. Sierra Valley
13ac. Upper Owens Valley
13ad. Mono-Adobe Valleys
13ae. Bishop Volcanic Tableland
8. Southern California Mountains
8a. Western Transverse Range Lower Montane Shrub and Woodland
8b. Western Transverse Range Montane Forest
8c. Arid Montane Slopes
8d. Southern California Subalpine/Alpine
8e. Southern California Lower Montane Shrub and Woodland
8f. Southern California Montane Conifer Forest
8g. Northern Transverse Range
14. Mojave Basin and Range
14a. Eastern Mojave Basins
14b. Eastern Mojave Low Ranges and Arid Footslopes
14c. Eastern Mojave Mountain Woodland and Shrubland
14e. Arid Valleys and Canyonlands
14f. Mojave Playas
14g. Amargosa Desert
14h. Death Valley/Mojave Central Trough
14i. Mesquite Flat/Badwater Basin
14j. Western Mojave Basins
14k. Western Mojave Low Ranges and Arid Footslopes
14l. Western Mojave Mountain Woodland and Shrubland
14m. Western Mojave High Elevation Mountains
14n. Mojave Lava Fields
14o. Mojave Sand Dunes
85. Southern California Coast
85a. Santa Barbara Coastal Plain and Terraces
85b. Oxnard Plain and Valleys
85c. Venturan-Angeleno Coastal Hills
85d. Los Angeles Plain
85e. Diegan Coastal Terraces
85f. Diegan Coastal Hills and Valleys
85g. Diegan Western Granitic Foothills
85h. Morena/Boundary Mountain Chaparral
85i. Northern Channel Islands
85j. Southern Channel Islands
85k. Inland Valleys
85l. Inland Hills
85m. Santa Ana Mountains
81. Sonoran Basin and Range
81a. Western Sonoran Mountains
81b. Western Sonoran Mountain Woodland and Shrubland
81c. Western Sonoran Basins
81d. Sand Hills/Sand Dunes
81e. Upper Coachella Valley and Hills
81f. Imperial/Lower Coachella Valleys
81g. Lower Colorado/Gila River Valleys
81h. Sonoran Playas
81i. Central Sonoran/Colorado Desert Mountains
81j. Central Sonoran/Colorado Desert Basins
81k. Arizona Upland/Eastern Sonoran Mountains

Jepson Flora Project Geographic Subdivisions
Please see Jepson eFlora: Geographic subdivisions.
Polygons are © 1993 Regents of the University of California.

Jepson Regions

Northwestern California
Cascade Ranges
Modoc Plateau
Central Western California
Great Valley
Sierra Nevada
East of Sierra Nevada
Southwestern California
Mojave Desert
Sonoran Desert

Historic Native American Tribal Territories
From Historic Native American Territories in California, a shapefile contributed to ArcGis Online by SaltonSea.

Based on Handbook of North American Indians Vol. 8. Smithsonian Institution, 1978. (SYNOPSIS).

For a more detailed view that includes languages, territories, and overlap, see the Native Land Digital map.

Coast Miwok
Eastern Miwok
Foothill Yokuts
Lake Miwok
Northern Paiute
Northern Valley Yokuts
Owens Valley Paiute
Southern Paiute
Southern Valley Yokuts
Western Shoshone

Geographic Grids

USGS quadrangle. In most of the continental United States, quadrangles are a geographic grid where the side of a grid cell is 1/8 of a degree: There are also irregular quads around islands and on the coast.

Quadrangle / 4
Quarter quadrangle. This is a geographic grid where the side of a grid cell is 1/16 of a degree. (When Calflora observations are obscured, they are displayed at the center of the containing quarter quadrangle.)

30 arcseconds
This is a geographic grid where the side of a grid cell is 1/120 of a degree.

Interlaced Metric Grids

The side of a grid cell is 5 kilometers; the area of a cell is 25 square kilometers.

The side of a grid cell is 2 kilometers.

The side of a grid cell is 1 kilometer.

100 M
The side of a grid cell is 100 meters.

Each climate and soil layer described here is presented as a abstract factor contributing to the characterization of a location. The choice of which factors to show as layers on Calflora maps is informed by USDA PLANTS Conservation Plant Characteristics (particularly Growth Characteristics), but within the pragmatic bounds of what data is available. The goal is to be able to use these factors as predictors of where various plants are likely to grow.

as prepared by the Prism Climate Group at Oregon State University, and available from the USDA Geospatial Data Gateway.

PRISM data is typically available as a raster, where a cell is 30 arcseconds (~ 800 m) on a side.

CITATION: U.S. Department of Agriculture, Natural Resources Conservation Service, National Geospatial Management Center

Average Annual Precipitation
Annual average precipitation during the period 1971 - 2000.

For predicting where a plant may grow, it is important to know the minimum annual precipitation it requires (and for certain plants, the maximum annual precipitation it will tolerate).

157 inches 399 cm
133 inches 338 cm
107 inches 272 cm
81 inches 206 cm
61 inches 155 cm
37 inches 94 cm
17 inches 43 cm
3 inches 8 cm

As presented in Calflora map applications, the colors indicating climate layers are continuous. Colors associated with selected values of Annual Precipitation are shown here.

Wet Season
The number of wet months, as derived from monthly average precipitation (1981 - 2010) cell data. For a particular month, an 30 arcsecond cell is considered wet if it receives at least 1.3 inches of precipitation.

As a characterization of location, this is similar to annual precipitation, but indicates the duration of a season during which rain is likely.

12 months

July High Temperature
based on average maximum monthly data during the period 1981-2010.

56 °F 13 °C
68 °F 20 °C
80 °F 27 °C
92 °F 33 °C
104 °F 40 °C
116 °F 47 °C

December Low Temperature
based on average minimum monthly data during the period 1981-2010.

8 °F -13 °C
16 °F -9 °C
24 °F -4 °C
32 °F 0 °C
40 °F 4 °C
48 °F 9 °C

Accumulated Temperature
based on average mean temperature and average minimum temperature monthly data during the period 1981-2010. This is a measure of accumulated heat during those months during which the minimum temperature is greater than 43 ° F (6 ° C). It is related to the concept of degree-days, but unlike degree-days calculated for a particular year, this number is based on average mean temperature. It is roughly equivalent to an annual sum of degree-days during the growing season.

In the context of these climate factors, accumulated temperature can help determine which places are too hot for a plant. It is particularly useful for differentiating very hot places (Death Valley) from moderately hot places (Fresno).

60 °F 16 °C
82 °F 28 °C
104 °F 40 °C
130 °F 54 °C
156 °F 69 °C
180 °F 82 °C
204 °F 96 °C
230 °F 110 °C
256 °F 124 °C
282 °F 139 °C
300 °F 149 °C
See also
    Wikipedia: Degree day:
      Total degree days from an appropriate starting date are used to plan the planting of crops and management of pests and pest control timing.

    Accumulated Temperature, Oxford Reference / A Dictionary of Ecology

A comparative study of different temperature accumulation methods for predicting the start of the Quercus pollen season in Cordoba (South West Spain), H. Garcia-Mozo, C. Galan, M. T. Gomez-Casero and E. Dominguez-Vilches, in Grama 39: 194-199, 2000

Temperature Range
Calculated as July High Temperature minus December Low Temperature per cell. In climate modelling, temperature range is akin to temperature seasonality.

In the context of these climate factors, temperature range is useful for differentiating coastal areas from inland areas. Coastal areas typically have a narrower temperature range than inland areas.

Two Coastal Vacciniums:
These two plants share much of their geographic range, but parvifolium extends further inland than ovatum. The difference is reflected in the Temperature Range value for each plant. The image below is a screen shot from What Grows Here, showing occurrences of the two plants in Humboldt County with Temperature Range as the background layer.

Note how the background color reveals temperature range differences between inland mountains (green ~ 48° F) and valleys (orange ~ 66° F).

10 °F -12 °C
24 °F -4 °C
36 °F 2 °C
48 °F 9 °C
54 °F 12 °C
60 °F 16 °C
66 °F 19 °C
76 °F 24 °C

Growing Season
The number of consecutive warm months, as derived from average minimum monthy temperature (1981 - 2010) cell data. For a particular month, a 30 arcsecond cell is considered warm if the average minimum temperature is at least 43 ° F (6 ° C).

12 months
≤ 1month

USDA Hardiness Zone
The map is based on average annual minimum winter temperature, divided into zones by 5 ° F increments. See the USDA Plant Hardiness Zone Map.

Hardiness Zone differs from December Low Temperature above, in that it reflects the lowest temperature that might ever be experienced at a location.

Units: degrees Fahrenheit

5a: -20 to -15
5b: -15 to -10
6a: -10 to -5
6b: -5 to 0
7a: 0 to 5
7b: 5 to 10
8a: 10 to 15
8b: 15 to 20
9a: 20 to 25
9b: 25 to 30
10a: 30 to 35
10b: 35 to 40
11a: 40 to 45

DISCLAIMER: Shapefiles of the hardiness zones for California were purchased and downloaded from Climate Source in February, 2014. They were subsequently modified (chopped into smaller pieces) for display as a map background layer.
USDA Agricultural Research Service Terms of Use: Data: Users may obtain enhanced (high resolution) official USDA Plant Hardiness GIS data in shapefile and raster grid formats from Climate Source, Inc. (www.climatesource.com/PHZM/gis_data.html), subject to Climate Source terms of use. The USDA-ARS and OSU logos must be prominently displayed on any maps derived from the GIS datasets. The data may not be altered in any way without an explicit and prominently displayed disclaimer that the map is not the official USDA Plant Hardiness Zone Map, and USDA-ARS and OSU logos must not be displayed in the modified version.
(See also GIS Data Downloads.)

Climate Source Inc. Notice: This product contains data from The Climate Source and is used herein by permission. Copyright (c) 2014 The Climate Source, www.climatesource.com. All Rights Reserved.
(See also License Agreement.)


from the Soil Survey Geographic (2.2) Database dated October 1, 2018. Updated on Calflora April 17, 2019 and again on September 20, 2019.
See also

SSURGO Table Struture
California is described by 18,960 mapunit records, each of which corresponds to one or more polygons.

Within each mapunit there are several soil component records. A component record has a percent (comppct_r) attribute, indicating its relative strength within the map unit.

A component record may be associated with several chorizon records. Each chorizon record has top depth (hzdept_r) and bottom depth (hzdepb_r) attributes specified in centimeters.

Click on the Derivation links below for more information about how the value displayed was derived from SSURGO data.

CITATION: Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Soil Survey Geographic (SSURGO) Database for California. Available online at NRCS Geospatial Data Gateway Accessed 04/10/2019.

Soil Depth
Minimum depth to the first restrictive layer of the components of a soil map unit.

Derivation: For 9,886 mapunit records, minimum depth was available from the brockdepmin (minimum depth to bedrock) attribute in the muaggatt table.

For the other mapunit records, minimum depth was calculated by choosing the deepest non-rock horizon of each component, and then averaging these numbers weighted by the component percent.

25 cm
40 cm
60 cm
140 cm
160 cm
250 cm

Soil pH
pH of the components of a soil map unit.

From Soil Properties and Qualities:

    "Soil reaction" is a numerical expression of the relative acidity or alkalinity of a soil. ... Soils that have a pH of approximately 6 or 7 generally have the most ready availability of plant nutrients.

See also this Calflora analysis of
how many plants tolerate each soil pH

Derivation: Each component record has one topmost chorizon record (where hzdept_r = 0). pH for the mapunit was calculated by averaging the chorizon ph1to1h2o_r attribute of these topmost horizons, weighted by the component percent.
  Class pH
  Extremely acid 3.5 to 4.4
  Very strongly acid 4.5 to 5.0
  Strongly acid 5.1 to 5.5
  Moderately acid 5.6 to 6.0
  Slightly acid 6.1 to 6.5
  Neutral 6.6 to 7.3
  Slightly alkaline 7.4 to 7.8
  Moderately alkaline 7.9 to 8.4
  Strongly alkaline 8.5 to 9.0

Soil CaCO3
The maximum calcium carbonate equivalent in the components of a soil map unit.

From Soil Properties and Qualities:

    “Calcium carbonate equivalent” is the quantity of carbonate (CO3) in the soil expressed as CaCO3 and as a weight percentage of the less than 2 mm size fraction.
    ... The availability of plant nutrients is influenced by the amount of carbonates in the soil. This is a result of the effect that carbonates have on soil pH and of the direct effect that carbonates have on nutrient availability.
Derivation: Each component record has one topmost chorizon record (where hzdept_r = 0). CaCO3 for the mapunit was calculated by averaging the chorizon caco3_r attribute of these topmost horizons, weighted by the component percent.

< 1 %
2.5 %
3.5 %
5.5 %
7.5 %
> 10 %

Available Water Storage

    The volume of water that the soil, to a depth of 100 centimeters, can store that is available to plants. It is reported as the weighted average of all components in the map unit, and is expressed as centimeters of water.
Derivation: Copied from the muaggatt table aws0100wta attribute.

AWS is calculated from AWC (available water capacity) which is commonly estimated as the difference between the water contents at 1/10 or 1/3 bar (field capacity) and 15 bars (permanent wilting point) tension, and adjusted for salinity and fragments.

1 cm
5 cm
10 cm
15 cm
20 cm
25 cm

Soil Salinity
as indicated by electrical conductivity. The maximum conductivity of the components of a soil map unit.

From Soil Properties and Qualities:

    Electrical conductivity is a measure of the concentration of water-soluble salts in soils. It is used to indicate saline soils. High concentrations of neutral salts, such as sodium chloride and sodium sulfate, may interfere with the absorption of water by plants ... [and] may also interfere with the exchange capacity of nutrient ions...
Derivation: Each component record has one topmost chorizon record (where hzdept_r = 0). Electrical conductivity for the mapunit was calculated by averaging the chorizon ec_r attribute of these topmost horizons, weighted by the component percent.

  Class Conductivity in mmhos / cm
  Non-saline0 to <2
  Very slightly saline2 to <4
  Slightly saline4 to <8
  Moderately saline8 to <16
  Strongly saline≥16

Soil Texture
Texture as used here is based on the texture description of the major component of a soil map unit. A typical categorization of textures is shown below (image from the NRCS Soil Texture Calculator).

From Soil Properties and Qualities:

    "Particle size” is the effective diameter of a particle as measured by sedimentation, sieving, or micrometric methods.
The broad classes are
  • clay  [<0.002 mm] (fine)
  • silt    [0.002 to 0.05 mm] (medium)
  • sand [0.05 to 2.0 mm] (coarse)
Derivation: Copied from the chtexturegrp table texdesc attribute, for the topmost horizon in the major (largest percentage) component of the mapunit.
Silty clay
Sandy clay
Silty clay loam
Clay loam
Sandy clay loam
Silt loam
Sandy loam
Loamy sand
Decomposed plant material
Muck / Peat

Ultramafic Areas
from the USGS showing

    Ultramafic rocks, mostly serpentine. Minor peridotite, gabbro, and diabase.

Unit 1: Trinity Ophiolite
Unit 2: Western Sierra Nevada and Klamath Mountains
(Late Proterozoic to Early Jurassic)
Unit 3: Coast Ranges and Western Klamath Mountains
(Middle to Late Jurassic)

From the USGS California geologic GIS dataset.

Igneous and Metamorphic, undifferentiated
Igneous and Sedimentary, undifferentiated
Igneous, intrusive
Igneous, volcanic
Metamorphic and Sedimentary, undifferentiated
Metamorphic, amphibolite
Metamorphic, carbonate
Metamorphic, gneiss
Metamorphic, other
Metamorphic, schist
Metamorphic, sedimentary clastic
Metamorphic, serpentinite
Metamorphic, undifferentiated
Metamorphic, volcanic
Sedimentary, carbonate
Sedimentary, chemical
Sedimentary, clastic
Sedimentary, undifferentiated
Unconsolidated, undifferentiated
More Information
Introduction to Calflora Map Applications

Calflora Plant Characteristics and Associations Help

Las Pilitas Nursery (native plant ranges and tolerances)

Release Notes

March 11, 2023
Added the geology layer, courtesy of USGS.

June 12, 2020
The SSURGO layers Texture and Available Water Storage were re-done with new colors.

March 1, 2020
Added ultramafic areas as a soil layer, courtesy of USGS.

September 20, 2019
The SSURGO polygons loaded last April were over optimized: when you zoomed very close, the boundaries between polygons did not meet smoothly. The SSURGO polygons were reloaded on September 20 without this over optimization problem.

Soil background layers will now appear on maps all the way out to zoom level 9.