Ottmar, Roger D.; Vihnanek, Robert E.; Wright, Clinton S. 2002. Stereo photo series for quantifying natural fuels. Volume Va: jack pine in the Lake States. PMS 837. Boise, ID: National Wildfire Coordinating Group, National Interagency Fire Center. 49 p.

A series of single and stereo photographs display a range of natural conditions and fuel loadings in jack pine ecosystems in the Lake States. 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, jack pine, Pinus banksiana.

COOPERATORS
This publication was developed by the USDA Forest Service, Pacific Northwest Research Station, Fire and Environmental Research Applications Team with funding provided, in part, by the Joint Fire Science Program.

ACKNOWLEDGMENTS
Special recognition is due Douglas Anderson, Fire Management Coordinator, Minnesota Department of Natural Resources; Valdo Calvert, USDA Forest Service, Huron Manistee National Forest; Michael Miller and Gary Olson, USDA Forest Service, Hiawatha National Forest; and Steve Holdsambeck, USDA Forest Service, Chequamegon National Forest. David Wright, Jared Mathey, Jennifer McCormick, Crystal Raymond, and Sonya Schaller, USDA Forest Service, Pacific Northwest Research Station worked on this project in the field and in the office.

AUTHORS
Roger D. Ottmar is a research forester, Robert E. Vihnanek is a supervisory forester, and Clinton S. Wright is a research forester, USDA Forest Service, Pacific Northwest Research Station, Forestry 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 one series. Each site contains the wide-angle (50 mm) photograph, general site, stand, and forest floor information, and summaries of overstory structure and composition, 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
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.

In the jack pine series, potential natural vegetation plant associations from the United States National Vegetation Classification within the terrestrial vegetation of the Midwestern United States region, were designated for each site based on vegetation structure and composition (Faber-Langendoen 1999). In addition, Society of American Foresters (SAF) cover type was assigned for each site based on descriptions in Eyre (1980). Society of American Foresters cover type is defined by current vegetation composition and locality or environmental factors.

STAND INFORMATION
Tree and understory species (shrub, forb, and graminoid species) present at a site are listed in order of abundance.¹ The listing of understory species was not meant to be a complete vegetation inventory and may represent only a portion of the actual species richness of the sampled areas. The percentage of dead standing trees (all stems greater than 4.5 feet tall) was determined by sampling within the site (fig. 1). Crown closure was either measured with a forest densitometer at 95 systematically located points in the sample area or, for forests with low tree cover or small stature, was estimated by using line intercept transects (Canfield 1941). Live seedling composition, density, and coverage were estimated by using twelve 0.005-acre circular plots representing 43 percent of the sample area; all trees less than 4.5 feet tall were considered seedlings.

1See below for a list of scientific and common species names used in this volume.

FOREST FLOOR INFORMATION
Surface material and duff depth were calculated as the average of measurements taken every five 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 different forest floor components was calculated as an average of the depth only where that component was encountered during sampling. Therefore, the depths reported for the different forest floor components are not unit-wide averages and do not necessarily sum to total depth. Loading was calculated from bulk density values derived from field measurements.² Constancy is an indicator of how consistently the various forest floor components occur in the sample area and is expressed as a percentage of the total number of measurements. The amount of exposed mineral soil at each site can be estimated by subtracting the constancy of the total forest floor from 100 percent.

2Forest floor bulk density values used for each material type are listed in "Notes to Users.".

SAPLINGS AND TREES
As with the seedlings, overstory trees and saplings were sampled in twelve 0.005-acre circular plots located systematically throughout the sample area or within the entire sample area for sites with low tree density (fig. 1). Tree measurement data were summarized by diameter at breast height (d.b.h.) size class and by tree status (all, live or dead).³ Height to crown base 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 values (i.e., live branches and foliage) were calculated from species- and size-specific allometric equations (Brown 1978, Clark et al. 1985, Crow 1983, Ker 1980, Loomis and Blank 1981, Reiners 1972, Roussopoulos and Loomis 1979, Singh 1981, Stocks 1980, Swank and Schreuder 1974). Crown mass equations for Acer pensylvanicum, Larix laricina, and Viburnum spp. were substituted with Acer glabrum, Larix occidentalis, and a general hardwood species equation, respectively.

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

UNDERSTORY VEGETATION
Understory species coverage was estimated by 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) by 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 (2.69 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). 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).⁴ 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 100-hour size classes for several of the sites) was determined by collecting, oven drying, and weighing all pieces in twelve 2.69-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 were calculated from relationships that use number of pieces intersected and transect length (and wood specific gravity for loading), respectively, developed by Brown (1974) and Safranyik and Linton (1987).

4Woody 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.

SPECIES LIST
Scientific and common species names are from NRCS (2001).

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.

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, 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.

Clark, A., III; Phillips, D.R.; Frederick, D.J. 1985. Weight, volume, and physical properties of major hardwood species in the Piedmont. Res. Pap. SE-255. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 78 p.

Crow, T.R. 1983. Comparing biomass regressions by site and stand age for red maple. Canadian Journal of Forest Research. 13: 283-288.

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

Faber-Langendoen, D. 1999. International classification of ecological communities: terrestrial vegetation of the Midwestern United States. Minneapolis, MN: The Nature Conservancy, Midwest Conservation Science Department. 645 p.

Ker, M.F. 1980. Tree biomass equations for ten major tree species in Cumberland County, Nova Scotia. Inf. Rep. M-X-108. Fredericton, NB: Environment Canada, Canadian Forestry Service, Maritimes Forest Research Centre. 26 p.

Loomis, R. M.; Blank, R.W. 1981. Estimating northern red oak crown component weights in the northeast United States. Res. Pap. NC-194. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station. 9 p.

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.

Natural Resources Conservation Service [NRCS]. 2001. The PLANTS database. Version 3.1. https://plants.usda.gov. (September 1st, 2002).

Reiners, W.A. 1972. Structure and energetics of three Minnesota forests. Ecological Monographs. 42: 71-94.

Roussopoulos, Peter J.; Loomis, Robert M. 1979. Weights and dimensional properties of shrubs and small trees of the Great Lakes conifer forest. Res. Pap. NC-178. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station. 6 p.

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.

Singh, T. 1981. Biomass equations for ten major tree species of the prairie provinces. Inf. Rep. NOR-X-242. Edmonton, AB: Environment Canada, Canadian Forestry Service, Northern Forestry Research Centre. 35 p.

Stocks, B.J. 1980. Black spruce crown weights in northern Ontario. Canadian Journal of Forest Research. 10: 498-501.

Swank, Wayne T.; Schreuder, Hans T. 1974. Comparison of three methods of estimating surface area and biomass for a forest of young eastern white pine. Forest Science 20(1): 91-100.