140 



X 



liJ 



o 



— 100 





6 8 10 



6-node span (feet) 



14 



Figure 8. --Graph for estimating site index from measurements 

 of 6-node span, with confidence limits for the 95 

 percent level of probability. 



Without exception the cotyledons and primary leaves of 1-year seedling white 

 spruce were serrulate on the margins (fig. 9) while similar leaves of black 

 spruce were entire. In addition, white spruce averaged more cotyledons per 

 seedling than black spruce. Serrulations proved to be a reliable characteris- 

 tic on seedlings up to about nine or ten years of age. The gap in identification 

 characteristics is between this age and the age when distinguishing features 

 characteristic of mature trees are developed. 



Additional details as well as a summary of the experience of other investigators 

 is given in Technical Note No. 45, "Identification of spruce seedlings in Inter- 

 ior Alaska". 



W Forest Soil Organic Layer Development. --Samples of unincorporated 



forest soil organic layers from three stands of different ages indicated the re- 

 lationship of weight to time shown in fig. 10. At the end of 125 years, 20 per- 

 cent of the mature weight was accumulated. An additional 50 percent was 



17 



