THE USE OF STAND GRAPHS IN DETERMINING THE 

 LIMITATION OF CUT 



By Hermann Krauch 



Forest Bxaminer, U. S. Forest Service 



The term "good forestry" implies that the forests are managed on 

 the basis of a "sustained yield." In order to accompHsh this, it is of 

 course necessary to have data showing the composition and rate of 

 growth of stands. Assuming that such data are available, it is possible 

 to determine the amount of timber which can be periodically removed 

 from a given area, in conformity with the principles of management. 

 Knowing the stand per unit of area, the percentage of timber that can 

 be cut, is readily computed. 



The application of this principle in the field is, however, not so 

 simple. Unless the forester records and computes the volumes of trees 

 retained during the process of marking, he has no satisfactory means 

 of judging the amount of timber he is leaving. In ordinary practice 

 such procedure is not feasible. The following method is therefore 

 suggested, as having a possible application in the execution of Na- 

 tional Forest timber sales. In order to describe the procedure, an 

 actual virgin stand will be considered.^ The tabulated data for this 

 stand show the merchantable volume (board feet) by inch-diameter 

 classes, and for young (black jack) and old (yellow pine) separately. 

 From these figures the accompanying graphs were compiled. 



The upper graph shows the composition of the stand according to 

 percentages of young (black jack) and mature (yellow pine) trees in 

 volume b. f. The amounts per acre are also indicated. The other 

 graphs show the percentages of trees in each diameter class and also 

 the corresponding percentages in volume. The values are plotted on 

 a scale of 10 inches, thereby making calculations a simple matter of 

 measurement. 



Let us suppose that a tract of yellow pine timber, of which the 

 example cited is typical, is to be marked for cutting. The field meas- 



' This area consists of 40 acres of virgin and verj- mature yellow pine in the 

 vicinity of the Ft. Valley Experiment Station, FlagstafT, Arizona. 



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