Table 3. --Percent of total slash volume by slash age 3 size, and 

 height above ground 







All-size slash 



0-1 cm. -size slash 



Height 





: : Old and 



: : Old and 



of slash 



Old 



: New : new 



Old : New : new 



Cm. ____________ Percent 



0-19 



52 



34 



43 



47 



48 



48 



20-39 



23 



38 



30 



32 



28 



29 



40-59 



13 



19 



16 



12 



14 



14 



60-79 



12 



5 



9 



4 



3 



3 



80-99 



< 1 



4 



2 



2 



4 



3 



100-119 



<1 



< 1 



<1 



2 



1 



1 



120-139 



< 1 



< 1 



< 1 



<1 



< 1 



< 1 



140-159 



<1 



< 1 



< 1 



<1 



<1 



< 1 



Fuel surface area, like volume, was concentrated in the lower portions of the 

 slash. About 68 percent of the total surface area was below the average mid-depth of 

 the slash. The relationship between cumulative percent surface area and depth is al- 

 most identical to that in figure 2. Differences in the proportions of surface area, 

 between small- and large-size material, and between new and old slash in the same strata, 

 averaged a maximum of three percentage points. 



Composition of Slash 



The species composition of the slash based on the proportion of all particle 

 intersections with all sampling planes was as follows: 



Percent of total 

 Species intersections 



Douglas-fir and subalpine fir 55.5 

 Spruce - 32.1 



Larch 8 . 1 



Lodgepole pine 4 . 3 



100.0 



The proportions of fuel volume and surface area by different-size material com- 

 prising the slash are shown in table 4. The new slash contained considerably larger 

 proportions of volume and surface area in the 0-1 size class than old slash because a 

 larger proportion of needles was attached to the branches in new slash. This is shown 

 in the following tabulation of needle volume and surface area, for all of the plots 

 expressed as a percent of the 0-1 size class volume and surface area: 



Slash age 



Average needle volume 

 (percent) 



Average needle surface area 

 (percent) 



Old 



New 



6.4 

 24.5 



13.5 

 41.7 



The 0-1 size class provided 79 percent of the fuel surface area in new slash but 

 only 49 percent in the old slash. This large proportion of fine-particle surface area 

 in new slash points out the higher potential flammability of new slash compared to old 

 s lash . 



6 



