0. 15 



0. 125 



r 0. 10 



I 



0.075 



0. 05 



0.025 



5 BRANCHES AND FOLIAGE 

 I FOLIAGE 



WH 



WP 



Figure IS.— Live crown bulk densities of dominants for foliage and for foliage and ^ 

 branchwood together. For all species coefficients of variation for bulk densities 

 of foliage and branchwood ranged from 22 to 65 percent^ and averaged 47 percent. 



Hence, bulk densities were altered more by omission of foliage-free cavities, as shown 

 by the average ratios of bulk densities including foliage-free cavities to those with- 

 out foliage-free cavities: 



Species Ratios 



L, WP, PP, LP, WBP 1.16 

 AF, GF, DF, WH, C, S 1.03 



To investigate the relationship between bulk density and d.b.h., regression 

 analysis using polynomial, exponential, and linear models was employed. Relationships 

 for only three species were significant and of these, the highest r^ was 0.33. Although 

 regression analyses failed to confirm relationships between bulk density and d.b.h., 

 a plot of bulk density over averages of d.b.h. groups indicates that bulk density de- 

 creases as d.b.h. increases, at least up to 4 inches d.b.h. (fig. 14). One exception 

 was ponderosa pine where bulk density increased with increasing d.b.h. Sample ponder- 

 osa pines of large d.b.h. were primarily from poor-to-medium sites. They supported 

 many heavy branches, 3 to 6 inches in diameter, that probably accounted for the in- 

 creased bulk density at large d.b.h. 



26 



