Figure 14. — Live orown bulk 

 densities for foliage and 

 branchwood of dominants re- 

 lated to d.b.h. Lodgepole 

 pine was omitted because 

 all of its sample trees were 

 less tlmn 2 inches d.b.h. 



0. 15 



0. 10 



>- 



1/1 



0.05 



0to2 



2 to 4 

 D. B. H. (IN) 



WBP 



4 + 



Bulk densities increased vertically through the crowns, as shown in the following 

 tabulation of live crown bulk densities: 



Species group 



Crown section 



Top Middle and bottom 

 (Founds per cubic foot) 



Ratio of top-to- 

 middle and bottom 



DF, GF, WP, PP, LP 

 AF, WBP 

 C, L 

 S 



WH 



0. 



123 

 225 

 060 

 114 



072 



0.075 

 . 110 

 .042 

 .102 

 .068 



1.6 

 2.0 

 1.4 

 1.1 

 1.1 



Bulk densities of each species in a group were within 10 percent of the group aver- 

 age. Engelmann spruce and western hemlock showed little variation in bulk densities 

 between the upper and lower portions of the crown. Most of these sample trees had small 

 d.b.h. The data for the other tolerant species indicate that variation in bulk density 

 between upper and lower crown sections is greater for large trees. Thus, larger spruce 

 and hemlock than studied here may show greater vertical variation in bulk density. 



Bulk density of intermediates was less than for dominants but only decidedly so for 

 grand fir, as shown in the following tabulation of intermediate-to-dominant bulk density 

 ratios : 



Intermediates-to -dominants ratios 

 Species Foliage and branches Foliage 



DF 0.80 (0.20) 0.81 (NS) 



PP .87 (NS) .92 (NS) 



C .93 (NS) .92 (NS) 



GF .66 (0.02) .56 (0.01) 



27 



