MEASURING THE FOREST CROP. 



INTRODUCTION. 



The methods of measuring wood when cut are well known. For 

 firewood and billets, for pulp wood, spokes, staves, etc., the cord of 128 

 cubic feet is employed; for telegraph poles, posts, etc., the linear foot, 

 with diameter limits, furnishes the measure; for saw logs various stand- 

 ard log rules are used, which pretend to give the amount of timber that 

 can be sawed from logs of given lengths and smallest measured diam- 

 eter. We say '^jjretend," for in fact the amounts given in these log 

 rules, or scalers^ books, do not in most cases coincide with the amount 

 obtained by the miller. That amount depends upon the care with which 

 the miller handles the log and the character of the saw he employs. 



It is not, however, the measuring of the cut wood that we propose to 

 discuss here, but the measuring of the standing crop as it is found in 

 the forest. This knowledge, not only of what amount of wood is stand- 

 ing on an acre at a given time, but what amount grows in a year or has 

 grown in a given period, is of great Importance with a crop which 

 requires many years to mature, and does not, likp a field crop, have a 

 definite period when it is ripe, but with which the harvest depends on 

 the question when it is profitable to cut the crop. 



The amount which grows each year varies at different periods of the 

 life of the crop, hence if we want to determine when it is most profitable 

 to cut the crop we must be able to measure its growth and to determine 

 whether the yearly or periodic increment is such as to make it desirable 

 to let the crop stand because it increases in value in due proportion to 

 the cost of its standing, or to cat it because the wood made per year 

 ceases to pay interest on the cost. 



In order to measure the amount of timber standing and the amount 

 of wood growing we must know the methods of measuring (1) the 

 contents of a single tree; (2) the contents of a stand of trees or grow- 

 ing stock; (3) the rate at which single trees and whole stands grow 

 under varying conditions and at various ages. 



While full knowledge of the subject may be acquired only by special 

 study and application, familiarity with the simplest method is within 

 the easy reach of everyone interested or engaged in lumbering or 

 forestry operations, and only the simplest methods are to be discussed 

 here. 



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