26 



BULLETIlSr 426, U. S. DEPARTMEK"T OF AGEICULTUEE. 



important than the total height. Because of its straightness, a very 

 large proportion of the bole of a sugar pile can be utilized. Further- 

 more, the lower branches of the crown fall off at a comparatively 

 early age, leaving an unusual clear length averaging 50 feet in nature 

 stands and not inf recju en tly reaching 80 feet. A table, based on a 

 large number of actual measurements, showing the merchantable 

 length of trees of various diameters and heights wiU be foimd in the 

 Appendix. 



DIAMETER GROWTH. 



Sugar pines of the largest diameters are found on the best sandy 

 loam soils in fairly open situations. Trees in dense forest, in compe- 

 tition with others for light, are obHged to devote their energy to 

 height growth largely. Table 17 shows maximum, average, and 

 minimum diameters based on age in virgin stands. 



Table 17. — Minimum, avei'age, and maximum groivth in diamet&f, on basis of age, 



California.. 



■ 

 Age. 



Diameter breast-high outside 

 bark, in inches. 



Age. 



Diameter breast-high outside 

 bark, in inches. 



Maxi- 

 mum. 



Average. 



Mini- 

 mum. 



Maxi- 

 mum. 



Average. 



Mini- 

 mum. 



Years. 

 20 



0.4 



4 



9.7 

 16.7 

 24.1 

 30.4 

 33.6 

 40.3 

 44.9 

 49.1 

 52.8 

 56.5 



0.2 



2.5 



7.5 



13.0 - 



18.1 



22.7 



■ 26.8 



30.5 



33.9 



37.0 



40.0 



42.5 





Years. 

 260 



60.1 



63.5 



66.9 



70 



73.3 



76.1 



44.9 

 47.2 

 49.3 

 51.4 

 53.5 

 55.5 

 57.3 

 59.1 



32.4 

 34.3 

 36.1 

 37.9 

 .39.5 



40 





2.S0 



60 



5.8 

 9.2 

 12.6 

 16.2 

 19.2 

 21.8 

 24.2- 

 26.4 

 28.6 

 30.5 



300 



80 



320 



100 



340 



120 



360 



140 



380 





160 



400 







180 



Number of 

 stump an aly- 

 ses 







200 



20 



474 



22 



220 



240 







The measurements upon which Table 17 is based were taken for 

 the purpose of showing the effect of locahty upon diameter growth 

 rather than the effect of various factors, such as soil, light, and mois- 

 ture, within a given locality. The maximum measurements were 

 secured among dominant trees within the western central Sierras, 

 the best range of the species. The minimum measurements were 

 taken among the same class of trees in Siskiyou County, northern 

 Cahfornia, toward the limit of the range. The average was obtained 

 by averaging the measurements taken in eight localities throughout 

 the State. The effect on the growth of unfavorable factors within a 

 given locahty approximates the effect of an unfavorable change in 

 latitude or altitude, however; therefore, the average growth shown 

 in the tables is indicative of the growth that trees somewhat crowded 

 for light, or growing on poorer soils, might make m a more central 

 portion of the range of the species. In the same way, the minimum 



