Fi gure 2 . — Gras s b lade s (top) ; 

 cone scale, staminate flower 

 leaf of woody plant, bark 

 flake (from left to right, 

 middle); and branchwood 

 (bottom) were miscellaneous 

 particles found in the 

 litter. 



data was used to estimate randomness of particle orientation and for testing a planar 

 intersect method for estimating fuel volume and surface area.^ 



After the litter was collected, the depth of the F layer was measured where the 

 perpendicular bisectors intersected the edges of the plot. Bulk density was computed 

 on an ovendry weight basis. Very little material collected below the L layer could be 

 identified as H layer material (Soil Sci . Soc. Amer. 1965, p. 9). 



Cheatgrass plots were established on a slight slope in a south-facing area approx- 

 imately 1 acre in size 6 miles west of Missoula, Montana (fig- 5). Six kinds of fuel 

 particles--stalks , leaves, peduncles, glumes, spikelets, and awns--were sampled 

 separately (fig. 6). 



Three zones containing heavy, moderate, and sparse amounts of fuel were delineated 

 on the ground. Plots 30 by 45 centimeters in size were randomly located in all three 

 zones. All fuel and approximately 5 centimeters of soil were lifted undisturbed into 

 flats and transferred to the laboratory for measurements. The measurements were 

 actually taken from an area 10 by 25 centimeters in each plot. A larger amount of 

 fuel than needed for measurements was collected to avoid disturbing fuel along the 

 small plot edges during the lifting process. 



In the laboratory, 15 sampling planes were randomly positioned through the fuel 

 in each plot using a sliding wire frame to delimit the sampling plane (fig. 7). The 

 wire frame, 2.5 centimeters wide, was moved horizontally through the fuel at various 

 elevations for a distance of 10 centimeters. Numbers of particles, by kinds, passing 

 through or touching the sampling plane were recorded; their angle of orientation with 

 respect to the sampling plane was estimated ocularly. For cheatgrass, locating sam- 

 pling planes horizontally facilitated the counting of particle intersections since 

 particles were oriented dominantly in the vertical direction. Particle orientation 

 was judged only with respect to the vertical direction. 



J. K. Brown. A planar intersect method for sampling fuel volume and surface area. 

 Intermountain Forest and Range Exp. Sta, , Ogden, Utah 84401. (In preparation.) 



Cheatgrass 



4 



