A SIMPLIFIED METHOD OF STEM ANALYSIS ' 



By T. W. Dwight 

 Assistant Director of Forestry, Department of the Interior, Canada 



From the standpoint of work involved, there lies a broad gap between 

 the ordinary methods of volume table work and "complete stem analy- 

 sis," greater than seems to be entirely justified by the difference in the 

 quantity of information secured in the two cases. A volume table gives 

 no data in regard to growth. The recognized methods of stem analysis 

 give very complete data on all growth relationships, but at a great cost 

 of effort and time. As American foresters have to deal with a large 

 number of commercially and silviculturally important species, most of 

 them ranging over large and variant territories, they have, and will have 

 for some time to come, to make shift with meager tables of growth. 

 Comparison of existing growth tables for a single species, which have 

 been prepared with the best methods, shows such great unexplained 

 variations between them as to point to the necessity for more numerous 

 studies of growth, so as to determine to some extent at least the various 

 factors responsible for those variations and the effect of those factors 

 in various localities. The purpose of this article is to suggest a way to 

 increase the number of such studies. 



There is at present but one well-recognized method of stem analysis. 

 This involves nine main operations. 



A. In field : 



1. Measurement of average d. b. h. 



2. Measurement of height of tree and length of each section. 



3. Decade measurements of stump diameter growth. 



4. Decade nieasxtrements of diameter growth at the upper end 



of each log along the average radius. 



B. In office : 



5. Preparation of volume table. 



6. Constructing diameter growth curve by plotting growth of 



each tree. 



7. Constructing height growth curve. 



8. Computing volume of each tree at end of every decade. 



9. Constructing volume growth curve by plotting volume of 



each tree at end of every decade. 



' Contribution from the Canadian Society of Forest Engineers. 

 864 



