Ottmar, Roger D.; Vihnanek, Robert E.; Wright, Clinton S.; Restaino, Joseph C. 2009. Photo series for quantifying natural fuels. Volume XI: eastern Oregon sagebrush. General Technical Report PNW-GTR-XXX. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 43 p.

A series of photographs display a range of natural conditions and fuel loadings for sagebrush types that are ecotonal with grasses, western juniper, and ponderosa pine in eastern Oregon. Each group of photos includes inventory information summarizing vegetation composition, structure, and loading; woody material loading and density by size class; forest floor depth and loading; and various site characteristics. The natural fuels photo series is designed to help land managers appraise fuel and vegetation conditions in natural settings.

Keywords: Woody material, biomass, fuel loading, natural fuels, sagebrush-steppe, ponderosa pine, Pinus ponderosa, western juniper, Juniperus occidentalis, yellow rabbitbrush, Chrysothamnus viscidiflorus, antelope bitterbrush, Purshia tridentata, big sagebrush, Artemisia tridentata, low sagebrush, Artemisia arbuscula, medusahead, Taeniatherum caput-medusae, crested wheatgrass, Agropyron cristatum, Thurber’s needlegrass, Achnatherum thurberianum.

COOPERATORS
This publication was developed by the US Forest Service, Pacific Northwest Research Station, Fire and Environmental Research Applications team with funding provided, in part, by the Bureau of Land Management and US Forest Service, Pacific Northwest Region, Fire and Aviation State Office/Regional Office.

ACKNOWLEDGMENTS
Special recognition is due; Joe Wagner, Bureau of Land Management, Department of the Interior, Lakeview Office; Gregg Riegel, USDA Forest Service, Department of the Interior, Deschutes National Forest; and Brian Watt, Bureau of Land Management, Department of the Interior, Vale Office. Jeff Kelly, Kyle Jacobson, Amy Jirka, Shawn Smith, and Aarin Sengsirirak, USDA Forest Service, Pacific Northwest Research Station, Pacific Wildland Fire Sciences Laboratory, worked on this project in the field and in the laboratory.

AUTHORS
Roger D. Ottmar and Clinton S. Wright are research foresters, Robert E. Vihnanek is a supervisory forester, and Joseph C. Restaino is a forestry technician, Pacific Northwest Research Station, Pacific Wildland Fire Sciences Laboratory, 400 North 34th Street, Suite 201, Seattle, Washington 98103.

PHOTOGRAPH AND INFORMATION ARRANGEMENT
The photographs and accompanying data summaries are presented as single sites organized into three series. Each site in the sagebrush with grass series is shown on a single page, and each site in the sagebrush with western juniper and sagebrush with ponderosa pine series is arranged to occupy two facing pages. In the case of facing pages, the upper page contains a wide-angle (35mm) photograph and general site and stand information. The lower page includes summaries of overstory structure and composition; understory vegetation structure and composition; litter and downed woody material loading and density by size class; and selected shrub species structure, biomass, and composition.

SITE AND STAND INFORMATION
The camera point of each site was located with a global positioning system (GPS) receiver using the WGS-84 datum. Aspect and slope were measured with a compass and clinometer, respectively. Ecological community classification (to the plant association level; NatureServe 2009), and cover type (SAF or SRM; Eyre 1980, Shiflet 1994), indicators of current vegetation composition, were assigned for all sites. Biophysical setting and succesional stage as defined by the LANDFIRE Biophysical Settings Model descriptions ( Rollins and Frame 2006) are also noted. Shrub, forb, and graminoid species coverage along with mineral soil exposure, was estimated by using line intercept transects (Canfield 1941). Species coverage is listed in order of abundance (a list of scientific and common species names used in this volume appears below). Where species-specific coverage is not reported, understory vegetation coverage was estimated by lifeform category (shrub, forb, or graminoid) by using the line intercept transects. The listing of species was not meant to be a complete vegetation inventory and may represent only a portion of the species richness of the sampled areas.

For the sagebrush-western juniper and sagebrush-ponderosa pine sites, crown closure was measured with a forest densitometer (155 systematically located points). Tree and seedling composition and density were determined by a total inventory of the sample area; all trees less than 4.5-feet tall were considered seedlings.

Figure 1--Photo series sample area layout. Forty random azimuth line transects (one at each point on the 30- and 150-foot arcs, and two at each point on the 60-, 90-, and 120-foot arcs) and 12 clipped vegetation plots (two to three per arc) were located within the sample area. Trees, shrubs and seedlings were inventoried within the entire sample area or on 12 systematically located sample plots.

VEGETATION
Vegetation heights were measured at 30 points located systematically throughout the sample area. Vegetation biomass was determined by sampling 13 square, clipped vegetation plots (21.53 square feet each for herbaceous species and small-stature shrubs, and 43.06 square feet each for large-stature shrubs) located systematically throughout the sample area (fig. 1). All live and dead vegetation rooted within each square plot was clipped at ground level, separated, and returned to the laboratory for oven drying. Vegetation and other collected materials was oven dried at a minimum of 158° F for at least 48 hours before weighing and determination of area loading. Shrub loading is the sum of all large- (Chrysothamnus viscidiflorus, Purshia tridentata, Artemisia tridentata, and Artemisia arbuscula) and small-stature shrubs.

FOREST FLOOR INFORMATION
For the sagebrush with western juniper series, litter and duff depth were calculated as the average of measurements taken every 5 feet between the 30- and 150-foot arcs of the three center transects for a total of 75 measurements (fig. 1). The depth of the litter and duff was calculated as an average of the depth only where litter or duff was encountered during sampling (null values, or points where litter or duff were absent, are not included in the average). Therefore, the depths reported for litter and duff are not unit-wide averages, and do not necessarily sum to total depth. Loading was calculated from depth and bulk density values derived from field measurements or, as was the case with the sagebrush with grass and sagebrush with Ponderosa pine sites, through collection of material in thirteen 21.53-square-foot plots.¹ Constancy, an indicator of how consistently the various forest floor components occur in the sample area, is expressed as a percentage of the total number of measurements.

1Forest floor bulk density values used for each material type appear under "Notes to Users" for each series.

WOODY MATERIAL
Measurement techniques used for inventorying dead and down woody material were patterned after the planar intersect method outlined by Brown (1974) and described by Maxwell and Ward (1980). Forty transects of random azimuth starting at 25 systematically located points within the sample area were used to determine woody material loading and density (fig. 1). Woody material data are reported by size classes that correspond to timelag fuel classes used in fire behavior modeling (see, for example, Burgan and Rothermel 1984).² Woody material in 1-hr, 10-hour, and 100-hour-and-larger size classes was tallied on transects that were 5, 10, and 30 feet long, respectively. The decay class and the actual diameter at the point of intersection were measured for all pieces >3 inches in diameter. All woody material less than or equal to 3 inches in diameter was considered sound. Woody material loading and woody material density were calculated from relationships that use number of pieces intersected and transect length (and wood specific gravity for loading) developed by Brown (1974) and Safranyik and Linton (1987), respectively. Woody material in the sagebrush with grass series was measured by collecting all 1-hr, 10-hr, and 100-hr pieces in thirteen 21.53-square-foot plots nested within the larger clipped vegetation plots. Collected woody material was oven dried and weighed to determine area loading. When woody material >3 inches in diameter was scarce, a total inventory of the sample area was conducted to determine loading and density estimates. Measurements were taken to determine log volume, and woody specific gravities were applied to the volume to calculate loading.

SAPLINGS AND TREES
Overstory tree and sapling composition and density were determined by a total inventory of the sample area. Tree measurement data were summarized by diameter at breast height (d.b.h.)³ size classes. Height to crown base (reported as ladder fuel height in previous photo series volumes) was defined as the height of the lowest, continuous live or dead branch material of the tree canopy, and height to live crown was defined as the height of the lowest continuous live branches of the tree canopy. Live crown mass (branchwood and foliage) was calculated from species- and size-specific allometric equations (Brown 1978, Gholz 1980).

3D.b.h. is measured 4.5 feet above the ground.

SELECTED SHRUB SPECIES
Individual plants of all large-stature shrub species (Chrysothamnus viscidiflorus, Purshia tridentata, Artemisia tridentata, and Artemisia arbuscula) were measured in systematically located plots (fig. 1). The density and percentage of all stems that were dead is based on the number of plants rooted in thirteen 43.06-square-foot plots. Crown area was calculated from crown breadth (i.e., the average of the maximum crown diameter, and the widest point perpendicular to the maximum crown diameter). Height is given as the average and maximum height of all sampled individuals of a given species. Live and dead branches of large-stature shrubs were separated following harvesting; live and dead material was further separated into size classes (foliage and £1 inch diameter branches and stems, and >1 inch diameter branches and stems).

SPECIES LIST
Scientific and common species names are from NRCS (2009).

LITERATURE CITED

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Brown, J.K. 1978. Weight and density of crowns of Rocky Mountain conifers . Res. Pap. INT-197. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 56 p.

Burgan, R.E. 1988. 1988 revisions to the 1978 national fire-danger rating system. Res. Pap. SE-273. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 39 p.

Burgan, R.E.; Rothermel, R.C. 1984. BEHAVE: fire behavior prediction and fuel modeling system--FUEL subsystem. Gen. Tech. Rep. INT-167. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 126 p.

Canfield, R.H. 1941. Application of the line interception method in sampling range vegetation. Journal of Forestry 39: 388-394.

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Eyre, F.H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [+ map]

Gholz, H.L. 1980. Structure and productivity of Juniperus occidentalis in central Oregon. American Midland Naturalist 103(2): 251-261

Maxwell, W.G.; Ward, F.R. 1980. Guidelines for developing or supplementing natural photo series. Res. Note PNW-358. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 16 p.

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Ottmar, R.D.; Vihnanek, R.E., Wright, C.S. 2007. Stereo photo series for quantifying natural fuels. Volume X: sagebrush with grass and ponderosa pine-juniper types in central Montana. Gen. Tech. Rep. PNW-GTR-719. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 59 p.

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