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

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.



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.

Metadata

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.)	0	0	5
CHP	CX (Montane chap)	0	0	4
CON	MP (mixed conifer)	1	2	5
CON	MP	3	8	9
CON	PP (ponderosa pine)	3	5	10
CON	PP	3	3	5
CON	PP	4	8	9
HDW	QC (canyon live oak)	0	0	6
HDW	QK (black oak)	0	0	9
HEB	HJ (grass, meadow)	0	0	1
NFO	BA (barren)	0	0	99
NFO	WA (water)	0	0	98

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	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

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
SSB SAGEBRUSH SHRUB
BB	BitterBrush
BC	Saltbrush
BR	Rabbit Brush
BS	Basin Sagebrush
BM	Mountain Mahogany
BL	Low Sagebrush
DSB DESERT SHRUB
DS	Shadescale
DL	Creosote
DA	Blackbush
DX	Mixed Desert Shrub
ASB ALPINE DWARF SCRUB
AC	Cushion Plant
AX	Mixed Alpine Scrub
HEB HERBACEOUS
HG	Annual Grass/Forbs
HJ	Wet Meadows Grass/Sedge/Rush
GR	Grass Speceis not determined
NFO NON-FOREST
WA	Water
BA	Barren
UB	Urban/Developed
AG	Agricultural
SN	Snow/Ice

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 (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 (CC)

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

Sample 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.