Wildland Fire Management Plan Craters of the Moon National Monument, Idaho

Appendix E - Supplemental Information on Fuel Types

The plant communities of CRMO are highly diverse and range from those on recent lava and cinder material to well-developed Douglas-fir and sagebrush communities. The majority of vegetation of CRMO is not included in habitat types developed for southern Idaho (Steele et al. 1981, Hironaka et al. 1983). Neither of these works included sagebrush-grass or limber pine vegetation on recent volcanic material. The vegetation on the well-developed soils of the Pioneer Mountain foothills and in the Carey Kipuka are included in one of these habitat type classifications. Day and Wright (1985) described 26 distinct vegetation community types within the monument. This study uses the same types. It was determined that 20 of these community types had potential to sustain fire and these were combined into the nine broad vegetation groups discussed below. The correspondence of these groups with the types described by Day and Wright (1985) and the area of each is described in Table 1.

Rate-of-spread, rate of growth, fire intensity, and flame length are among the characteristics that can be estimated through the use of Rothermel's fire behavior model (1972) and Albini's nomograms (1976) and the PC version of BEHAVE (PC/BEHAVE)(Cooney 1986).The models do possess a number of general limitations and specific limitations related to sage communities. Brown's (1982) predictions are useful in predicting fire behavior in big sagebrush communities. PC/BEHAVE allows the use of the standard NFFL fuel models but also allows the user to develop custom fuel models that reflect existing vegetation and fuels. The result is better prediction of fire behavior for the site. Custom fuel models were developed to represent the conditions present in CRMO vegetation (Table 4). These are intended as initial fuel models to be modified further as the personnel of CRMO validate models as time progresses and actual field observations can be made.

The fixed inputs in the custom fuel models were extracted from information collected in the field at CRMO. Dead, live woody and herbaceous fuel loading information are summarized for the vegetation groups in Tables 5 and 6. Fuel depth data were extracted from Table 7 by vegetation group. This information is also available for each of the 20 community types described by Day and Wright (1985) that were sampled. Other values shown in Table 4 were determined through the experience of the authors and with the assistance of the PC/BEHAVE documentation. Fuel moisture of extinction is the fine fuel moisture at which the fire can no longer sustain itself. It is a sensitive variable in light fuels such as are present at CRMO. This variable requires further adjusting to the conditions present at CRMO as these data become available.

As an example of the use of this information, fire behavior was predicted for a mixture of mountain big sagebrush (85%) and low sagebrush (15%) vegetation. Inputs are shown in Table 8 and outputs in Table 9. The model can estimate fire behavior for a single vegetation type or it can utilize 2 vegetation types and calculate weighted values.

The predicted fire behavior for this example is included in Table 9. The rate-of-spread for the big sagebrush type is 80 m/hr (4 chain/hr) (1 chain = 66 ft). The rate-of-spread declines to 4 m/hr (13 ft/hr) when the fire burns into the low sagebrush vegetation type which indicates that the fire probably cannot sustain itself in this vegetation under these conditions and will go out. This is a realistic prediction as the fuels in low sagebrush are often inadequate to carry low intensity fires. Flame length and fireline intensity relate directly to the difficulty of fire control. When these values exceed 1.2 m (4 ft) and 80 Kcal/m/s (100 Btu/ft/m), respectively, the fire is normally too intense to be controlled directly by hand crews at the head of the fire. If flame length and fireline intensity exceed 3 m (10 ft) and 400 Kcal/m/s (500 Btu/ft/m), respectively, direct attack with machines is not advised. The fire in this example could be readily controlled with suppression crews. Areas dominated by low sagebrush vegetation could be used as fire control points.

The above parameters have been entered into NEWMODEL to create four fuel models specific to CRMO and are in the BEHAVE file titled CRMOMDLS (found in C:\FIRE). The four models are:

By using BEHAVE FIRE1 these models will represent fire behavior in the various fire management unit based on actual conditions. Observed versus predicted conditions will be used to validate the fuel model.

Table 1. Areas occupied by each of the major plant communities, and their correspondence with areas mapped by Day and Wright (1985).

Table 2. Effects of fire on understory species common to vegetation types of Craters of the Moon National Monument. More information on fire response of each species can be found in Harniss et al. (1981), Tisdale and Hironaka (1981), Wright and Bailey (1982), Blaisdell et al. (1982), and Bunting et al. (1987).

Table 3. Parameters for the custom fuel models to be used in PC/BEHAVE for predicting fire behavior in non-forested vegetation types in Craters of the Moon National Monument (Data collected on site by the authors).

1) Imperial units of measure are used by PC/BEHAVE program as inputs and outputs.

Table 4. Parameters for the custom fuel models to be used in PC/BEHAVE for predicting fire behavior in forested vegetation types in Craters of the Moon National Monument (Data collected on site by Park Personnel).

1) Imperial units of measure are used by PC/BEHAVE program as inputs and outputs.

Table 5. Down woody and duff fuel loadings for major vegetation type in Craters of the Moon National Monument (Data collected on site by Park Personnel).

MBS=Mountain big sagebrush, TTS=Three-tip sagebrush, LS=Low sagebrush, AB=Antelope bitterbrush, GBW=Great Basin wildrye, LP=Limber pine/bitterbrush, DF=Douglas-fir, UQA=Upland quaking aspen, RZ=Riparian zone

Table 6. Percent cover by herbaceous plant growth form, herbaceous production, plant litter and plant interspace in major plant communities in Craters of the Moon National Monument to assist in quantifying fire effects. (Data collected on site by Park Personnel).

MBS=Mountain big sagebrush, TTS=Three-tip sagebrush, LS=Low sagebrush, AB=Antelope bitterbrush, GBW=Great Basin wildrye, LP=Limber pine/bitterbrush, DF=Douglas-fir, UQA=Upland quaking aspen, RZ=Riparian zone. Desirable spp. within the interspaces represent available spp. to respond favorably to fire, usually 18% to 23% or greater of total cover.

Table 7. Mean shrub canopy coverage (cc, %) and height (ht, cm) from sample plots on Craters of the Moon National Monument (Data collected on site by Park Personnel).

MBS=Mountain big sagebrush, TTS=Three-tip sagebrush, LS=Low sagebrush, AB=Antelope bitterbrush, GBW=Great Basin wildrye, LP=Limber pine/bitterbrush, DF=Douglas-fir, UQA=Upland quaking aspen, RZ=Riparian zone

AMUT-serviceberry, ARAR-low sagebrush, ARTRV-mountain big sagebrush, ARTRI-three-tip sagebrush, CHNA-rubber rabbitbrush, CHVI-low rabbitbrush, LEPU-prickly phlox, PRVI-chokecherry, PUTR- bitterbrush, RIAU-golden currant, RICE-squaw currant, SYOR- snowberry, TECA-gray horsebrush.

Table 8. Example of fuel and weather input for utilizing PC/BEHAVE fire behavior program. (Information collected from field measurements at time of fire).

Table 9. Predicted fire behavior in mountain big sagebrush (85%) and low sagebrush vegetation when burning under the conditions specified in Table 10 when using PC/BEHAVE.

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