Approximately three-fourths of the cutting deple- 

 tion during the period 1925-36 was of privately 

 owned timber. It is assumed that this ratio will 

 probably hold for 1936-45, but that by the begin- 

 ning of the second decade many of the operations 

 in privately owned ponderosa pine will be cut out. 

 The cut of publicly owned and Indian timber will 

 probably increase during the second decade, but 

 since such timber is not available for unrestricted 

 cutting the increase will not offset the decrease 

 in cut of private timber. It is therefore es- 

 timated that the cutting depletion during the 

 period 1946-55 will average 1,435 million board 

 feet. 



By the third decade, 1956-65, the bulk of the 

 privately owned ponderosa pine will probably have 

 been logged and most of the cut will come from 

 national-forest and Indian-owned timber. Like- 

 wise, by this date probably most of the timber 

 regardless of ownership will be under sustained- 

 yield management and the cut will be governed 

 chiefly by the productive capacity of the forests. 

 Considering the ownership of the remaining timber 

 and its sustained-yield capacity, and other fac- 

 tors, it was assumed that cutting depletion in the 

 third decade would average 1,220 million board 

 feet. 



In estimating future losses due to fire, records of 

 fires that occurred during the period 1924-35 

 were analyzed and a rate of area deforested annu- 

 ally was computed for each type. The types were 

 then combined into 11 groups and a net annual 

 rate for each group assigned. Based on the group 

 rates, the average annual area to be deforested in 

 the future was estimated at 30,000 acres. The 

 volume of timber killed annually, determined 

 through application of average stand-per-acre 

 figures to the areas of merchantable types deforested, 

 is estimated to be approximately 80 million board 

 feet. 



Table 20. — Assumed future average annual forest depletion in 



the ponderosa pine region, log scale, Scribner rule 



[In million board feet, i. e., 000,000 omitted] 



Form of depletion andsurveyunit 



1936-45 



1946-55 



1956-65 . 



Cutting depletion: 



Eastern Washington: 

 Chelan-Colville. 



185 

 175 

 20 



155 

 150 

 20 



140 



Yakima River- 



135 



North Blue Mountain 



20 



Total 



380 



325 



295 







Eastern Oregon: 



North Blue Mountain. .__ 

 Deschutes River 



South Blue Mountain 



Klamath Plateau 



125 

 325 

 250 

 665 



105 

 290 

 200 



515 



100 



225 

 185 

 415 







Total 



1,365 



1,110 









Region total 



1,745 



1, 435 



1 220 







Fire depletion: 



Eastern Washington: 

 Chelan-Colville 

 Yakima River 



17 

 17 

 1 



17 



17 



1 



17 

 17 



North Blue Mountain 



1 



Total 



35 



35 









Eastern Oregon: 



North Blue Mountain 



Deschutes River 



8 

 11 

 11 

 15 



8 

 11 

 11 



15 



8 



South Blue Mountain 



Klamath Plateau 



11 







Total 



45 



45 









Region total . 



80 



80 



80 





Total depletion: 



Eastern Washington: 

 Chelan-Colville... 

 Yakima River 



202 

 192 

 21 



172 

 167 

 21 



157 

 152 



North Blue Mountain 



21 



Total 



415 



360 



330 







Eastern Oregon: 



North Blue Mountain 



Deschutes River. 



South Blue Mountain 



Klamath Plateau.. 



133 

 336 

 261 

 680 



113 

 301 

 211 

 530 



108 

 236 

 196 

 430 







Total 



1,410 



1,155 



970 







Region total . - . 



1,825 



1,515 



1,300 



42 



