INTRODUCTION 



The volume of timber cut or killed during logging 

 operations and left in the woods represents a reduc- 

 tion in the inventory volume available for future 

 management and harvesting. Consequently, the volume 

 of unused timber should be taken into consideration 

 if differences between successive inventories are to 

 be more fully understood. Estimates of the amount of 

 logging residue potentially marketable as chips are 

 of interest also. 



In 1968, Forest Survey at the Intermountain 

 Forest and Range Experiment Station conducted a survey 

 of logging residues in Arizona and New Mexico. Log- 

 ging residue surveys yield various types of infor- 

 mation, ^ but only data considered to be sufficiently 

 reliable for purposes of this report were used here. 

 Information not included in the present paper may be 

 combined with data from future residue surveys of 

 other areas to provide adequate reliability for fur- 

 ther analyses. Since 1965, Forest Survey has surveyed 

 logging residues in Idaho, Montana, Colorado, Utah, 

 Wyoming, and in South Dakota west of the 103d meridian. 

 If present plans are adhered to, residues will be re- 

 surveyed periodically in all Mountain States. 



Conversion factors to be applied to product vol- 

 umes for estimates of total volumes removed from in- 

 ventory in commercial logging; average conversion 

 factors used to express product volume in several 

 units of measure (cubic feet. International 1/4-inch 

 rule, and Scribner log rule); the diameter distribu- 

 tion of trees removed from inventory by logging; the 

 proportion of timber products harvested from growing 

 stock trees compared to that of products from non- 

 growing stock trees; cull and breakage losses by 

 species; the relative importance of felling and skid- 

 ding as causes of residues; and the proportion of 

 logging residue volume made up of pieces of various 

 size classes. 



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