encountered. Subsequent dendrometer measurements will continue for this tree on the 

 next card. The tip for each fork except the last is indicated by a slash (/) in XTERM 

 of the last card containing data for that fork. 



Dendrometry of the two lowest measurement levels may not be feasible. Accordingly, 

 NETVSL follows the STX procedure^ for substituting tape-measured diameters and lengths. 

 Initial TGRADS should be recorded as a fictitious -999. Then initial FGRADS should be 

 the stump diameter outside bark, in inches and tenths. The corresponding SINELV should 

 be the length between stump top and the next measurement level, recorded in feet and 

 tenths with the decimal point punched. Second TGRADS should be blank, while second 

 FGRADS should be the diameter at the next measurement level (usually b.h.). Second 

 SINELV is recorded as length (in feet and tenths with decimal point punched) between 

 this measurement level and the first actually dendrometered measurement level above. 

 Examples to illustrate these procedures are provided in appendix A. 



TERMINATING PROCEDURE 



Transition from cards containing data for one tree to cards for the next tree is 

 indicated by the change in tree number (felled-tree data) or by the terminal asterisk 

 (dendrometry data). The end of a plot is indicated by a blank card. That is, a blank 

 card will suffice so long as the preceding tree number is nonzero. 



A second blank card indicates the end of a problem, and a third blank card 

 terminates the run. 



CALCULATION PROCEDURES 

 GEOMETRIC ASSUMPTIONS 

 Tree Bole 



Wood volume and surface area below the first diameter measurement are computed as 

 though the stump were a cylinder of the given length and diameter. The diameter of 

 the uppermost section of each fork must be zero. If the field measurements do not 

 include the tip of the tree, a fictitious section of trivial length and zero diameter 

 will suffice to permit computation to proceed. No attempt will be made to extrapolate 

 beyond the actual measurements. The volume, area, and any interpolated diameters in 

 the section terminating at the tip are computed as though the section were a right 

 cone. Intervening sections of normal taper are treated as right parabolic frustra. 

 Hence, their volume in cubic feet is computed by Sraalian's formula, and the surface 

 area as the surface of revolution of the appropriate parabolic segment. If the diameter 

 at the top of a section exceeds the next lower diameter, the intervening section is 

 treated as an inverted right conic frustrum. 



Cull Columns 



For each cross section, the area of each cull column is computed by the equations 

 shown in table 2 associated with their respective shapes, the dimensions W and B of the 

 cull column cross section, and the bole diameter, D. The volume in cubic feet of a 

 cull column between two succeeding sections is computed by assuming the following geo- 

 metric shapes having the indicated end areas. 



This description is paraphrased from the comments in SBR subroutine written by L. R. Grosenbaugh. 



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