TABLES FOR APPROXIMATING VOLUME GROWTH OF INDIVIDUAL TREES 



By 



P. D. Kemp and M. E. Met calf 

 Division of Forest Economics 



Introduction 



Foresters are frequently asked: How much has this tree grown in volume 

 in the last 10 years, or, what is the current rate of volume growth? 

 The answer to such questions usually requires rather complex computa- 

 tions. To simplify this task a set of volume growth tables 1/ has been 

 prepared for the folloxving species: ponderosa pine in western Montana, 

 and western larch, western white pine, and ponderosa pine in North Idaho. 



These growth tables were derived from average-height volume tables. Ap- 

 plication of these tables requires only a diameter determination and a 

 radial growth measurement either (l) number of annual rings in the outer 

 radial inch, or (2) the number of years (rings) in a specified radial 

 increment in inches. Field checks show that the growth of single trees 

 can be determined from the tables within 15 percent of a precise determi- 

 nation two out of three times. The tables express volume growth in three 

 ways : 



1. Annual board-foot (Scribner) growth of trees by diameter class 

 and radial increment. 



2. Average annual board-foot (Scribner) growth percent of trees by 

 diameter class and radial increment. 



3. Periodic (10 years) board-foot (Scribner) growth of tress by 

 diameter class and radial increment. 



To facilitate the determination of growth of trees differing in diameter 

 from the midpoint of the class and for growth rates between those in- 

 dicated, the growth should be plotted over d.b.h. and curved in ordinary 

 cross-section paper. This will not give a precise determination for the 

 individual tree, of course, because it still does not take into account 

 variations from average changes in height, form and bark thickness with 

 changes in diameter. Nevertheless, the curved volumes and tables permit 

 useful approximations of the volume growth of individual trees. 



1/ Copies of the 12 tables included in this paper are available in pocket 

 size (5" x 7g") and may be obtained upon request. 



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