4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. Ill 



the trees for HPC 7 to 9 was chosen at an elevation of approximately 

 8,000 feet. Here ponderosa pines were more mature and more domi- 

 nant than at the other two sites. The trees grew on top of a very 

 gently sloping terrace whose edge stood 20 feet above the stream 

 channel. Toward the south the terrace top rose gently to a steeper, 

 heavily wooded slope over 400 feet away. The soil, granitic in com- 

 position, contained numerous pebbles and boulders. 



Individual tree and core descriptions are given below in concise 

 form: 



HPC I. Ponderosa pine (Pinus ponderosa) . 14 inches DBH. Average thick- 

 ness of growth layers 1.61 mm. Range 1850-1946. Growth-layer sequence vari- 

 able. Average departure from mean 0.58 mm., or 26 percent. 



HPC 2. Ponderosa pine. 12 inches DBH. Distant 100 yards from HPC i. 

 Average thickness of growth layers 1.86 mm. Range 1850-1946. Growth-layer 

 sequence variable. Average departure from the mean 0.54 mm., or 29 percent. 



HPC 2. Foxtail pine (F. aristata). 24 inches DBH. Midway between HPC i 

 and 2. Average width of growth layers 1.32 mm. Range 1770- 1946. Growth- 

 layer sequence variable. Average departure from mean 0.51 mm., or 39 percent. 



HPC 4. White fir (Abies concolor). 15 inches DBH. Wettest location for 

 group east of Pass; slight drainage toward tree. Average thickness of growth 

 layers 2.93 mm., corrected to average 1.46 mm. Range 1880-1946. Growth-layer 

 sequence only fairly variable. Average departure from mean 0.57 mm., or 39 

 percent. 



HPC 5. Douglas fir (Pseudotsuga taxif alia) . 15 inches DBH. Average width 

 of growth layers 1.16 mm. Range 1810-1946. Growth-layer sequence variable. 

 Average departure from mean 0.45 mm., or 39 percent. 



HPC 6. Foxtail pine. 14 inches DBH. Distant 20 yards from HPC 5. Aver- 

 age width of growth layers 1.38 mm. Range 1820- 1946. Growth-layer sequence 

 uniform. Average departure from mean 0.36 mm., or 26 percent. 



HPC 7. Ponderosa pine. 23 inches DBH. Distant 70 feet from edge of 

 terrace above stream. Average thickness of growth layers 1.91 mm. Range 

 1830-1946. Growth-layer sequence uniform and rhythmic. Average departure 

 from mean 0.52 mm., or 27 percent. 



HPC 8. Ponderosa pine. 13 inches DBH. Distant 20 feet from edge of terrace 

 above stream. Least mature. Ground-water relations make site better drained 

 than that of HPC 7. Average thickness of growth layers 3.74 mm. ; corrected 

 to average 1.46 mm. Range 1897-1946. Growth-layer sequence only fairly vari- 

 able. Average departure from mean 0.53 mm., or 36 percent. 



HPC 9. Ponderosa pine. 19 inches DBH. Midway between terrace edge and 

 base of steep slope. Wettest location for trees west of Pass. Average thickness 

 of growth layers 2.71 mm.; corrected to average 1.46 mm. Range 1857-1946. 

 Growth-layer sequence variable. Average departure from mean 0.44 mm., or 

 30 percent. 



The designations variable, fairly variable, or uniform were assigned 

 directly from the wood by visual judgment alone. 



