Ottmar, Roger D.; Vihnanek, Robert E; Regelbrugge, Jon C. 2000. Stereo photo series for quantifying natural fuels. Volume IV: pinyon-juniper, sagebrush, and chaparral types in the Southwestern United States. PMS 833. Boise, ID: National Wildfire Coordinating Group, National Interagency Fire Center. 97 p.
Three series of single and stereo photographs display a range of natural conditions and fuel loadings in pinyon-juniper, sagebrush, and chaparral types in the Southwestern United States. Each group of photos includes inventory information summarizing vegetation composition, structure and loading, and as appropriate, 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, pinyon-juniper, pinyon pine, Pinus edulis, Pinus monophylla, juniper, Juniperus monosperma, Juniperus osteosperma, sagebrush, Artemisia, chaparral, coastal sage scrub.
COOPERATORS
This publication was developed by the USDA Forest Service, Pacific
Northwest Research Station, Fire and Environmental Research Applications Group, under
contract with the U.S. Department of the Interior.
ACKNOWLEDGMENTS
Special recognition is due Ken Kerr, Grand Canyon National Park; Jim Cunio, Royal
Gorge Resource Area, Bureau of Land Management; Ed Skerjanec and Mike Smith, Pike-San
Isabel National Forest; Robert E. Means, Elko Field Office, Bureau of Land Management.
AUTHORS
ROGER D. OTTMAR is a research forester, and ROBERT E. VIHNANEK is a supervisory
forester, USDA Forest Service, Pacific Northwest Research Station, Pacific Wildland Fire
Sciences Laboratory, 400 N 34th Street, Suite 201 Seattle, Washington 98103. At the
time this research was conducted, JON C. REGELBRUGGE was an Ecologist, USDA Forest
Service, Pacific Southwest Research Station, Riverside Fire Laboratory; he is currently a
Lands and Resource Officer, USDA Forest Service, San Bernardino National Forest, San
Jacinto Ranger District, P.O. Box 518, Idyllwild, CA 92549.
PHOTOGRAPH AND INFORMATION ARRANGEMENT
The photographs and accompanying data summaries are presented as single sites organized
into three series. Each site contains the wide-angle (50 mm) photograph, general site
information, shrub structure and composition data, and as appropriate, seedling
information, summaries of overstory and understory vegetation structure and composition,
and dead and down woody material loading and density by size class.
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 10-15 clipped vegetation plots (two to three per arc)
were located within the sample area. Trees, shrubs and seedlings were inventoried on 12
systematically located sample plots.
SITE INFORMATION
For all series the camera point of each site was located with a global positioning system
(GPS) receiver using the WGS-84 datum. Elevation was derived from topographic maps or by
using the GPS.
In the pinyon-juniper series, Society of American Foresters (SAF), and Society for Range Management (SRM) cover types, indicators of current vegetation composition, were assigned for each site (Eyre 1980, Shiflet 1994). Tree and litter coverage were estimated with a series of line intercept transects (Canfield 1941). Litter depth was measured at between 20 and 80 locations distributed randomly throughout the sample area, where litter was present. Litter loading was calculated from the above mentioned depth and cover data and bulk density values derived from field measurements. Total aboveground biomass includes litter and all live and dead woody material and vegetation.
In the sagebrush and chaparral series, the principal species occurring at a site are listed, although not necessarily in the order of abundance.1 The listing of species is not meant to be a complete vegetation inventory and may represent only a portion of the actual species richness of the sampled areas. The SRM cover type was assigned for each site (Shiflet 1994). For the sagebrush series, total aboveground biomass includes litter and all live and dead woody material and vegetation. For the chaparral series, stand age, litter loading, and shrub composition are reported. Stand age is the time since the last fire occurred in the sample area as determined from historical records. Study sites in the chaparral series were sampled as part of several different studies. Therefore, the methodology differed somewhat among sites. Where reported (for coastal sage scrub sites CH 01CH 03), litter loading was determined by collecting litter in three 43.06-square-foot sample plots located in and around the sample area. Shrub composition and density, where reported (for chamise chaparral sites CH 05CH 08 and ceanothus mixed chaparral sites CH 12CH 14, and CH 16), were determined by sampling in three 172.22-square-foot square plots located in and around the sample area.
1See below for a list of scientific and common species names used in this volume. |
SEEDLINGS
Seedling composition, density, and loading were determined using twelve 0.005-acre
circular plots representing 43 percent of the sample area for the pinyon-juniper series.
An individual of a species regarded as a tree that was less than 4.5 feet tall was
considered a seedling.
TREES
For the pinyon-juniper series, depending on stand density, overstory trees were sampled
either in the entire sample area, or in twelve 0.005-acre circular plots located
systematically throughout the sample area (fig. 1). Tree measurement data were summarized
by basal diameter size class. Basal diameter was measured above the root collar. Height to
crown was defined as the height of the lowest continuous live or dead branches of the tree
canopy. Crown breadth was defined as the average of two crown diameter measurements: (1)
maximum diameter, and (2) the widest point perpendicular to the maximum diameter. Crown
area was calculated from crown breadth. Aboveground mass values (i.e., bole, branches, and
foliage) were calculated from species-specific allometric equations (Meeuwig 1980, Miller
et al. 1981, Clary and Tiedemann 1986, Weaver 1986, Grier et al. 1992).
SHRUBS
Sites in the chaparral series were sampled as part of several different studies.
Methodology, therefore differed somewhat among sites, but all methods allowed for the
calculation of fuel loading by fuel components and plant species. All sites were located
in stands with relatively homogeneous structure and species composition. Shrubs were
collected on either three 172.22-square-foot plots (CH 05CH 08, CH 12CH 14,
and CH 16), three 43.06-square-foot plots (CH 01CH 03), or nine 43.06-square-foot
plots (CH 04, CH 10, and CH 11) randomly located in and around the sample area to
determine loading by species for 14 of 16 sites. Shrub loading by species was estimated
based on site-specific regression equations and the dimensions of all plants occurring in
either a 1,550.00-square-foot plot (CH 15), or a 4305.55-square-foot (CH 09) plot for the
remaining two sites. All shrubs rooted within the 14 smaller plots were cut at ground
level and weighed whole in the field immediately after cutting. Several individuals of
each species, representing a range of sizes, also were separated into their component
parts and returned to the laboratory for oven drying (185 °F to a constant moisture
content) and weighing to determine moisture content and component fractions. Component
fractions represent size classes that correspond to timelag fuel classes used in fire
behavior modeling (see, for example, Burgan and Rothermel 1984).2
Using ratio estimators for species-specific moisture content and component fractions,
field weights were adjusted yielding ovendry loading by component on an area basis for
each species.
2Woody material <=0.25 inch, 0.26-1.0 inch and 1.1-3.0 inches, and >3.0 inches in diameter corresponds to 1-, 10-, 100- and 1000-hour timelag fuels, respectively. |
SELECTED SHRUB SPECIES
Individual plants of selected shrub species were measured in circular plots for the
sagebrush and pinyon-juniper series. Selected species were those with a predominantly
single-stem growth form and included Cercocarpus ledifolius, Purshia mexicana,
and species in the genus Artemisia. In addition, limited data on species with a
predominantly multi-stem growth form are reported in the sage series; such species include
Krascheninnokovia lanata and species in the genus Chrysothamnus. The
density and percentage of all stems that were dead is based on the number of plants rooted
in 12 circular plots ranging from 0.0025-acre to 0.005-acre each. As with the trees, 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). Basal diameter was
measured above the root collar. In addition, the height, the proportion of crown that was
dead in the stand, the cover, and the loading were estimated for the sagebrush series. The
height is reported as the mean of all the heights of all individuals of a given species
sampled. A visual estimate of the percentage of the dead portion of the crown of each
plant sampled also was made and averaged to determine the dead crown proportion in the
stand. Cover was estimated using line intercept transects (Canfield 1941). Loading for
each species was estimated based on species-specific allometric equations (Uresk et al.
1977, Weaver 1986), with the exception of Artemisia nova which was clipped in
twelve 10.76-square-foot clipped vegetation plots.
UNDERSTORY AND VEGETATION
Understory species coverage (all species coverage in the sagebrush series) was estimated
using line intercept transects (Canfield 1941). Where species-specific coverage is not
reported, understory vegetation coverage was estimated by lifeform category (shrub, forb,
or graminoid) using the line intercept transects. Understory vegetation heights were
measured at 25 points located systematically throughout the sample area. Understory
vegetation biomass was determined by sampling 12 square, clipped vegetation plots (10.76
square feet each) also located systematically throughout the sample area (fig. 1). All
live and dead vegetation within each square plot was clipped at ground level, separated,
and returned to the laboratory for oven drying. Understory vegetation and other collected
material were ovendried at a minimum of 158 °F for at least 48 hours before weighing and
determination of area loading.
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). Where appropriate, 40 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). As with the shrub data for the chaparral series, woody
material data are reported by size classes that correspond to timelag fuel classes used in
fire behavior modeling. Woody material in 10-hour and 100-hour and larger size classes was
tallied on transects that were 10 feet and 30 feet long, respectively. Woody material
loading in the 1-hour size class (and the 10-hour and larger size classes for several of
the sites in the sagebrush series) was determined by collecting, ovendrying, and weighing
all pieces in twelve 10.76-square-foot sample plots. The decay class and the actual
diameter at the point of intersection was measured for all pieces >3 inches in
diameter. All woody material <3 inches in diameter was considered sound. Woody material
loading and woody material density (for the pinyon-juniper series) 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.
SPECIES LIST
Scientific and common species names are from NRCS (1999).
SCIENTIFIC NAME | COMMON NAME | SCIENTIFIC NAME | COMMON NAME |
TREES Cercocarpus ledifolius Cercocarpus montanus Juniperus monosperma Juniperus osteosperma Juniperus scopularum Pinus edulis Pinus monophylla Quercus gambelii SHRUBS Adenostoma fasciculatum Ammannia spp. Arctostaphylos glandulosa Artemisia californica Artemisia cana Artemisia nova Artemisia tridentata Ceanothus crassifolius Ceanothus megacarpus Ceanothus oliganthus Ceanothus spinous Chrysothamnus spp. Encelia californica Eriogonum cinereum Hazardia squarrosa |
Curl-leaf mountain mahogany Alderleaf mountain mahogany Oneseed juniper Utah juniper Rocky Mountain juniper Twoneedle pinyon Singleleaf pinyon Gambel oak Chamise Redstem Eastwood's manzanita Coastal sagebrush Silver sagebrush Black sagebrush Big sagebrush Hoaryleaf ceanothus Bigpod ceanothus Hairy ceanothus Redheart Rabbitbrush California brittlebush Coastal buckwheat Sawtooth goldenbush |
SHRUBS (CONT'D) Heteromeles arbutifolia Krascheninnokovia lanata Malosma laurina Opuntia spp. Purshia mexicana Quercus berberidifolia Rhamnus ilicifolia Ribes spp. Salvia leucophylla Salvia mellifera Symphoricarpos spp. Tetradymia spp. Yucca baccata Yucca whipplei FORBS Antennaria spp. Arenaria fendleri Aster spp. Eriogonum spp. Lupinus spp. GRAMINOIDS Bromus tectorum |
Toyon Winterfat Laurel sumac Pricklypear Cliff rose Scrub oak Hollyleaf redberry Currant San Luis purple sage Black sage Snowberry Horsebrush Banana yucca Chaparral yucca Pussytoes Fendler's sandwort Aster Buckwheat Lupine Cheatgrass |
LITERATURE CITED
Brown, James K. 1974. Handbook for inventorying downed woody material. Gen. Tech. Rep. INT-16. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 24 p.
Burgan, Robert E.; Rothermel, Richard 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.
Clary, Warren P.; Tiedemann, Arthur R. 1986. Distribution of biomass within small tree and shrub form Quercus gambelii stands. Forest Science. 32(1): 234-242.
Eyre, F.H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [+ map].
Grier, Charles C.; Elliott, Katherine J.; McCullough, Deborah G. 1992. Biomass distribution and productivity of Pinus edulis-Juniperus monosperma woodlands of north central Arizona. Forest Ecology and Management. 50: 331-350.
Maxwell, Wayne G.; Ward, Frank 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.
Meeuwig, R.O. 1979. Growth characteristics of pinyon-juniper stands in the western Great Basin. Res. Pap. INT-238. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 22 p.
Miller, Elwood L.; Meeuwig, Richard O.; Budy, Jerry D. 1981. Biomass of singleleaf pinyon and Utah juniper. Res. Pap. INT-273. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 11 p.
Natural Resources Conservation Service [NRCS]. 1999. The PLANTS database. Baton Rouge, LA: U.S. Department of Agriculture, National Plant Data Center. (https://plants.usda.gov/plants)
Safranyik, L.; Linton, D.A. 1987. Line intersect sampling for the density and bark area of logging residue susceptible to the spruce beetle, Dendroctonus rufipennis (Kirby). Inf. Rep. BC-X-295. Victoria, BC: Canadian Forestry Service, Pacific Forestry Centre. 10 p.
Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p.
Uresk, D.W.; Gilbert, R.O.; Rickard, W.H. 1977. Sampling big sagebrush for phytomass. Journal of Range Management. 30(4) : 311-314.
Weaver, T. 1986. Estimation of Cercocarpus ledifolius biomass and leaf area index: three methods. Proceedings of the Montana Academy of Sciences. 46: 67-74.