Surface Fuels Maps and Data

Cross Section of Fuel Map from Northern Sacramento Valley
to Portola

Below is a typical Fuel Model Map produced from Fuel Model GIS data for a slice of Northeastern California . The thumbnail pictures (not the actual location) indicate the type of vegetation and fuel loads associated with each fuel model shown in the key. By clicking on the thumbnail photos, you can obtain more detailed technical information about each fuel model.

Click thumbnail photos for details of each fuel model

Cross Section of Fuel Map from Northern Sacramento Valley to Portola

Surface Fuels Background

The California Interagency Fuel Mapping Group (CAIFMG), a consortium of State and Federal agencies, is developing regional "surface fuel" maps that span jurisdictional boundaries. Surface fuels are vegetative materials near the ground through which fire will spread. These materials range from downed woody material (leaf litter, dead branches and logs) to brush and grass. The amount, size and moisture content of surface fuels determines how fast a fire spreads, how hot it burns and how high its flames reach.

Figure 1. Inputs for Fuel Model

CAIFMG develops surface fuel maps by translating vegetation information from a variety of sources (see figure 1) into fuel characteristics, combining them with topographic and historical fire data and patching them together to form a seamless GIS fuels coverage. This process, known as "crosswalking," was originally developed by the Sierra Nevada Ecosystem Project (SNEP), and translates information on plant species, crown cover and tree size into 13 fuel behavior models based on the "Fire Behavior Prediction System" (FBPS). The "crosswalk" process also includes other factors, such as slope, aspect and elevation data to further refine fuel models. Finally fire history information defines areas where surface fuel characteristics change in order to account for past fires and subsequent regrowth (see fuel dynamic pathways for more details).

The scale and date of vegetation data from local, state and federal agencies often vary and therefore the scale and date of the resulting fuel data vary. The scale of the source data control the minimum mapping unit (MMU), the smallest area that can be uniquely identified on the map . The MMU for fuels data developed by CAIFMG ranges from 900 square meters up to 100 hectares. The final data are maintained as raster GIS coverages in an Albers equal area projection with a cell size of 30 meters on a side.

Other Uses of Fuel maps

State and Federal fire protection agencies combine regional fuel maps with other geographic information to identify and prioritize projects. CDF combines surface fuels with slope data to rank areas as moderate, high and very high fuel rank. This initial surface fuel rank is then associated with generalized ladder and crown fuel estimates to derive a final fuel assessment and ranking. As part of the California Fire Plan, CDF combines these fuel rankings with weather, assets at risk and historic level of service to identify and prioritize pre-fire projects. Similarly, the USFS, BLM and NPS use surface fuel maps to implement the Federal Wildland Fire Policy and to identify and plan pre-fire projects that reduce fire hazard and ultimately improve ecosystem health. These data are also used by the USFS in a variety of planning and assessment projects, including environmental impact reports, the Sierra Conservation Strategy and detailed Land Management Planning documents.


Fuel models are based on vegetation attributes, such as cover type, vegetation type, size and crown closure, as well as other factors, such as slope, aspect, elevation and topography.

In Table 1, each row represents a unique combination of inputs in the GIS database. The first row in table 1 below refers to a general cover type of "Chaparral" (CHP) then a more specific vegetation type of "Sierran foothill mixed chaparral" (CC) with no tree size (0) and no crown cover (0) because it is a non tree vegetation type. These inputs are categorized or "crosswalked" to a fuel model 5 (low shrub).

Table 1. Sample Table to be used in GIS analysis
Cover Type Veg Type Size Crown Cover Fuel Model
CHP CC (mixed chap.)
CHP CX (Montane chap)
CON MP (mixed conifer)
CON PP (ponderosa pine)
HDW QC (canyon live oak)
HDW QK (black oak)
HEB HJ (grass, meadow)
NFO BA (barren)
NFO WA (water)

Crosswalks similar to those used by Sapsis and others (1996) in the Sierra Nevada Ecosystem Project translate the vegetation coverage to a "Fire Behavior Prediction System" (FBPS) fuel model coverage.

Sample Data Fields

Cover Type Cover Type
Cover Type Description
CON Conifer Forest / Woodland
HDW Hardwood Forest / Woodland
CHP Chaparral
SCH Soft Chaparral
SSB Sagebrush Shrub
DSB Desert Shrub
ASB Alpine Dwarf Scrub
HEB Herbaceous
NFO Non-Forest

Veg Type Vegetation Type
Code Description Code Description
  Conifer Types   Hardwood Types
RW Redwood QK Black Oak
RD Redwood - Douglas Fir QD Blue Oak - (Gray Pine)
DP Douglas-Fir-Pine QC Canyon Live Oak
DW Pacific Douglas-Fir QA Coast Live Oak
DF Douglas-Fir (Tanoak-Madrone) QN Englemann Oak
DF Bigcone Douglas-Fir QW Interior Live Oak
GF Grand Fir QG Oregon White Oak
RF Red Fir QL Valley Oak
AB Santa Lucia Fir QM Maple-Dogwood
WF White Fir QT Tanoak - Madrone
MF Mixed Conifer Fir QH Black Oak
PB Brewer Spruce QR Red Alder
EA Englemann Spruce QE White Alder
SG Sitka Spruce - Grand Fir QY Willow-Alder
PM Bishop Pine QO Willow
BP Bristle Cone Pine QS Willow-Aspen
PC Coulter Pine QQ Quaking Aspen
FP Foxtail Pine QJ Cottonwood-Alder
JP Jeffery Pine QF Cottonwood
KP Knobcone Pine QX Black Cottonwood
PL Limber Pine QI Buckeye
LP LodgePole Pine QU CA Bay
PR Monterey Pine QB CA Bay Buckeye
PP Ponderosa Pine QZ Eucalyptus
PJ Single Leaf Pinyon QP CA Sycamore
PT Torrey Pine    
WW Western White Pine   CHP CHAPARRAL
WB Whitebark Pine CA Chamise
MP Mixed Conifer - Pine CR Red Shanks
MC Cuyamaca Cypress CC Sierran Foothill Mixed Chaparral
MG Gowen Cypress CD Southern Mixed Chaparral
MN Macnab Cypress CQ Mixed Chaparral
MO Modoc Cypress CQ Northern Mixed Chaparral
MM Monterey Cypress CV Tobacco Brush
MI Piute Cypress CL Wedgeleaf Ceanothus
MY Pygmy Cypress CX Montane Chaparral
MZ Santa Cruz Cypress CH Huckleberry Oak
MS Sargent Cypress CM Montane Mixed Shrub
MT Tecate Cypress CK Coyote Brush
MH Mountain Hemlock CS Scrub Oak
WJ Western Juniper CJ Brewer Oak
BT Big Tree
EP Eastside Ponderosa Pine   SCH SOFT CHAPARRAL
MB Mixed Pine w/ Giant Sequoia SB Buckwheat
SA Sub-Alpine Conifer SS California SageBrush
PO Port-Orford-Cedar SP Sage
PD Gray Pine    
CN Conifer Species not Determined    
BB BitterBrush    
BC Saltbrush    
BR Rabbit Brush    
BS Basin Sagebrush    
BM Mountain Mahogany    
BL Low Sagebrush    
DS Shadescale    
DL Creosote    
DA Blackbush    
DX Mixed Desert Shrub    
AC Cushion Plant    
AX Mixed Alpine Scrub    
HG Annual Grass/Forbs    
HJ Wet Meadows Grass/Sedge/Rush    
GR Grass Speceis not determined    
WA Water    
BA Barren    
UB Urban/Developed    
AG Agricultural    
SN Snow/Ice    

Size Size (Conifer Types)
Code Description
N Non-Stocked
0 Seedlings (Derived From Plantation Age)
1 Saplings (Derived From Plantation Age)
2 Poles Crown Diameter Less then 12 feet
3 Small Crown Diameter From 12 to 24 feet
4 Medium Crown Diameter From 24 to 40 feet
5 Large Crown Diameter Greater Than 40 Feet
6 Two Storied Overstory of sizze class 4 or 5 cannot exceed 20 percent Cover,
Distinct Understory layer of size class 2 or 3, two size classes less than
overstory, Understory cover at least 40 percent
X Not Determined

Size Size (Hardwood Types)
Code Description
N Non-Stocked
0 Seedlings
1 Saplings Crown Diameter Less then 15 feet
2 Poles Crown Diameter From 15 to 30 feet
3 Small Crown Diameter From 30 to 45 feet
4 Medium Crown Diameter Greater than 45 feet
X Not Determined

Crown Cover Crown Cover (CC)
Code Percent Crown Cover
0 0 %
1 1 - 20 %
2 20 - 30 %
3 30 - 40 %
9 90 - 100 %

Sample Map

Sample Fuel Map

AEU (Amador El Dorado Ranger Unit) Fuels and Fire History Map including Amador, El Dorado, Sacramento Counties and portions of San Joaquin
Vegetation data from a variety of sources were reinterpreted into 13 Fire Behavior models and patched together to provide a complete surface fuel coverage.

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