VOLUME GROWTH IN AN INDIVIDUAL TREE 63 



Directions: 



A. Data Required. — Total ages and ring counts (decade measurements not 



needed) at various intervals along the boles of the trees, recorded with 

 the heights above the surface of the ground at which the counts are 

 made. Whenever height growth studies are made in connection with 

 some study, not involving complete stem analysis, such for example, as 

 diameter growth at the stump, it is necessary to make ring counts at 

 various intervals along the bole for the height determinations. 

 Usually a good height growth table can be made from a much smaller 

 number of trees than required for diameter growth. Use data Series IV. 



B. Method of Procedure. 



1. Determine which is the independent and which the dependent variable. 



Ask the instructor if you are right, then lay off the cross-section 

 paper accordingly. 



2. Determine the number of years required to grow to the height of the 



cross-cut in question by subtracting the number of rings at the 

 various cross-cuts from the total age. 



3. Plot the values, average, and read off the proper kind of table. 

 Note in this problem the value of plotted points for interpolating 



values. 



Illustration II. — To Construct a Table of Height Growth for Uneven, or 

 Many-aged Stands, Based on D.B.H. 



Explanation. — This exercise aims to throw the student upon his own responsi- 

 bility and should be written out instead of being worked out. 



Directions. 



A. Data. — Determine first what data (enumerating all measurements) are 



required. 



B. Method of Procedure. 



1. Outline the method step by step. 



Suggestion. — Take into consideration the fundamental differences in 

 the construction of growth tables in even- and in uneven-aged stands 

 as illustrated in Problems 26 and 27, and apply to Height Growth. 

 Determine first which is dependent and which independent variable, 

 and whether you would use M. A. G. or Per. G. according to the pro- 

 cedure in many-aged stands. If you have any difficulties read again 

 the Explanation to Problem 27. 



PROBLEM 30. (Office.) The Determination of Volume Growth in an 

 Individual Tree. 

 Explanation. — Volume growth may be based on stem analysis data or on 

 measurements taken on a large number of standing trees of different ages. 

 In the first case the trees are analyzed in the field as in Problem 7 and the 

 volumes of the trees at different ages are reconstructed from the analysis. In 

 the second case average trees in even-aged stands of different ages are meas- 



