Table 25. — Comparison of current, probable as of 1966, and 

 potential annual conifer increment in the ponderosa pine region 



ACTUAL VALUES 



Kind of annual growth 

 calculation 



Area 

 involved 



Increment 

 on all trees 



5.1+ 

 inchesd.b.h. 



Increment 

 on all trees 



11. 1 + 

 inchesd.b.h. 



Current, 1936 



Thousand 

 acres 

 4,117 



10,282 

 9,499 

 8,139 



16,168 



Million 

 cubic feet 

 138 



366 

 326 

 266 

 658 



Million 

 board feet 

 219 



Probable, 1966: 



50-5(11 



9IX) 



75-50". 



815 



95-75' 



615 





2,037 







RATTO TO POTENTIAL VALUES 



Current. 1936 

 Probable, 1966: 



50-50 ' . 



75-50 »_ 



95-75 1 



Percent 



44 

 40 

 30 



1 Assuming 50 percent volume removal on all lands during first cutting 

 cycle. 



i Assuming 75 percent volume removal on private lands, 50 percent on 

 other lands. 



J Assuming 95 percent volume removal on private lands, 75 percent on 

 other lands. 



expected in time to increase materially, but such 

 growth will for many years be low in quantity and 

 even more so in quality. Differences in site- 

 quality class of the areas shown in table 25 are 

 negligible; average site quality of the areas in 



growing stands approximates that for the region's 

 total area of commercial forest land. 



The probable annual growth estimates as of 

 1966 are derived from the periodic growth calcu- 

 lations. If past cutting practice continues, about 

 8.1 million acres will be occupied by growing 

 stands by 1966 and their estimated net annual 

 growth as of that date is 255 million cubic feet or 

 615 million board feet. Light thrifty maturity 

 selection cutting applied to ponderosa pine stands 

 of all ownerships could increase saw-timber growth 

 to 900 million board feet by 1966. 



Effectiveness of Past Forest Practice 



Since nearly three-quarters of the commercial 

 forest land is occupied by mature stands that are 

 making no current net growth, a regional compari- 

 son of current growth with total potential growth is 

 of little value as an index of the effectiveness of 

 past forest practice. It is more appropriate to 

 compare current and potential growth on the 

 4% million acres of commercial forest land that 

 is not occupied by virgin timber, of which 94 per- 

 cent is now supporting growing stands of some 

 sort and the remaining 6 percent is deforested. 

 Here current growth in cubic feet is 73 percent 

 but in board feet only 37 percent of the potential 

 (table 26). Current growth in both cubic measure 

 and board measure is less than the potential in 



Table 26. — Current and potential growth on commercial forest land in the ponderosa pine region, exclusive of land occupied by mature timber 



State and unit 



Area 



Current annual 

 growth 



Potential annual 

 growth 



Ratio of current to 

 potential growth 





Cubic feet 



Board feet 



Eastern Washington: 



Chelan-Colville 



Thousand 

 acres 

 1,239 



755 

 164 



Million 



cubic feet 



32 



26 



6 



Million 

 board feet 

 64 

 50 



7 



Million 

 cubic feet 

 53 

 37 



7 



Million 



board feel 



155 



126 



21 



Percent 

 60 



70 

 86 



Percent 

 41 

 40 



North Blue Mountain 



33 







Total... 



2, 158 



64 



121 



97 



302 



66 



40 



Eastern Oregon: 



North Blue Mountain . 



857 

 435 

 497 

 567 



29 

 16 

 16 



13 



39 

 16 

 18 



25 



34 

 17 

 19 

 23 



97 

 57 

 60 



75 



85 

 94 

 84 

 57 



40 



Deschutes River 



28 



South Blue Mountain .. 



30 



Klamath Plateau _ __ 



33 







Total 



2,356 



74 



98 



93 



289 



80 



34 



Region total 



4,514 



138 



219 



190 



591 



73 37 











49 



