Forest Mensuration 45 



CHAPTER III. INCREMENT 



SECTION I. INCREMENT OF A TREE. 

 PARAGRAPH LXXII. 



THE KINDS OF INCREMENT. 



The following kinds of increment must be distinguished: 



a. Increment of height, diameter, sectional area and volume. 



b. Current annual increment, current periodic increment and total in- 

 crement. 



c. Average annual increment, average periodic increment and average 

 increment at the age of maturity. 



d. Increment of the past and increment of the future. 



e. Absolute increment and relative increment. 



The increment of stems cut down is found by counting and measuring 

 the annual rings on several cross sections. 



The term "stem" or "tree analysis" designates an investigation into the 

 past height growth, diameter growth and volume growth of a tree. 



Circular 445 of the Bureau of Forestry defines the term "increment," 

 somewhat narrowly, as follows: "The volume of wood produced by the 

 growth in height and diameter of a tree or of a stand." 



For definition of the term "tree analysis," see Circular 445 of Bureau 

 of Forestry. 



This circular distinguishes between : 



1. Stump-analysis, being a tree analysis which includes measure- 



ments of the diameter growth at given periods on the stump 

 only, no matter what other measurements it may comprise; 



2. Section-analysis, being a tree analysis which includes measure- 



ments of the diameter growth at given periods upon more 

 than one section of a tree ; 



3. Partial tree (stump or section) analysis, wherein the measure- 



ment of the diameter growth at given periods covers a portion 

 only of the total diameter growth. 



PARAGRAPH LXXIII. 



HEIGHT INCREMENT. 



The height increment, from the silvicultural standpoint, is of interest 

 to the forester dealing with mixed woods. 



The difference between the number of rings found on two separate cross 

 sections through the bole indicates the number of years which the tree 



