Table 3 shows the total number of growing stock 

 trees (product trees and others) , removed per 1 MCF 

 of product volume in New Mexico, in Arizona, and in 

 the New Mexico-Arizona area. These figures can be 

 applied to a given volume of saw log harvest to esti- 

 mate trees removed in each diameter class. In turn, 

 this estimate can be related to an inventory stand 

 table in order to compute cutting rates. 



SURVEY METHODS 

 AND RELIABILITY OF ESTIMATES 



A basic need in the logging residue surveys was 

 to develop factors that could be applied to a re- 

 ported volume of saw log harvest to estimate the 

 resulting volume of logging residues. Estimates of 

 residue volume are based on product volume rather than 

 acreage logged because such information usually is more 

 reliable and available (at least to Forest Survey) 

 than are estimates of area cutover. The survey design 

 prescribed three basic types of measurements of grow- 

 ing stock trees on active logging operations to meet 

 this objective: 



1. Net volume of saw logs harvested from 

 product trees measured on a logging 

 operation; 



2. Net volume of residues from the scone 

 trees ; 



3. Net volume of residues from other trees 

 cut or destroyed in the process of 

 felling and skidding product trees. 



All three sets of measurements were used to 

 determine the residue volume as a percent of saw log 

 volume. Scaling was done in detail to permit esti- 

 mates of gross and net cubic-foot volumes for all 

 measured growing stock trees, and to provide gross 

 and net board-foot volumes to fixed and variable tops 

 for measured sawtimber trees. Species, diameter breast 

 height (d.b.h.), total height, overutilization (by 

 Forest Survey standards), and cause of residue (fell- 

 ing or skidding) were recorded. 



6 



