equal to gross growth. Normal mortality rates 

 for even-aged immature stands were automati- 

 cally allowed for by use of the normal yield tables. 

 Loss in the uneven-aged immature stands, how- 

 ever, was computed as a separate step. For such 

 stands estimated loss (as percent of volume in 

 reserve stand at start of growth period) varied con- 

 siderably, depending on estimated gross growth, 

 but averaged about 0.55 percent annually. The 

 relation between annual loss as percent of volume 

 and gross growth was based on the measurements 

 of mortality (from all causes) made by Meyer (77) 

 on 169 of the 179 sample plots upon which his 

 growth study was based. 



Methods in Requirements Phase 



The requirements phase of the forest survey con- 

 sisted in a determination of present and prospec- 

 tive requirements for wood products. Estimates of 

 the quantities of these products needed in the 

 future cannot be made solely on the basis of needs 

 within the region. Interchange of products be- 

 tween regions necessitates determination of future 

 requirements on a national basis, followed by 

 allocation of the quantity determined among the 

 several timber-producina; regions. Nevertheless 

 requirements for certain classes of wood materials 

 must be computed separately for each region. 

 Estimates of future requirements were based 

 upon studies of (1) urban construction needs, (2) 

 rural construction needs, and (3) the requirements 

 of the secondary wood-using industries. In the 

 Pacific Northwest studies were made of the first 

 two subjects named. 



The complete results of the requirements studies 

 made in this region are not presented in this report. 

 They will be integrated and correlated with data 

 from other regions and published in a report on 

 national requirements. 



It is manifest that the Pacific Northwest with its 

 extensive and varied forest resources and sparse 

 population can supply its requirements for prac- 



tically all kinds of forest products indefinitely. The 

 only wood products consumed in this region that 

 must be imported are small amounts of hardwood 

 material such as flooring and interior finish, and 

 articles manufactured of woods not grown in this 

 region, such as certain kinds of furniture and imple- 

 ment handles. The principal sources of these items 

 are eastern and southern United States, the Philip- 

 pine Islands, and South and Central America. 



Supplemental Tables 



In this report all saw-timber volume data have 

 been expressed in log scale, Scribner rule. How- 

 ever, in some of the other regions in the United 

 States similar data are expressed in lumber tally. 

 For the purpose of comparison, tables showing saw- 

 timber volume data in lumber tally for this region 

 have been prepared. These are included in this 

 section as supplemental tables. 



Table 33 shows the volume of timber in millions 

 of board feet, lumber tally, in the region by species 

 and forest-survey unit, and table 34 by species and 

 ownership class. 



A comparison of annual saw-timber growth and 

 depletion, in millions of board feet, lumber tally, is 

 shown by unit in table 35. Also shown in lumber 

 tally is the current annual gross growth in the 

 region by unit and broad age class in table 36, cur- 

 rent and potential annual net growth in the region 

 by unit in table 37, and periodic net saw-timber 

 growth in the region, 1936-65, by unit, decade, and 

 class of cutting practice in table 38. 



Detailed fire-depletion data are given in supple- 

 mental tables as follows: Table 39 shows the area 

 deforested on national forests and lands other than 

 national forests in the region in 1924-35, inclusive, 

 by type and forest-survey unit; table 40 shows the 

 loss of timber volume in log scale on the same areas; 

 and table 41 is a regional summary of estimated an- 

 nual average of area deforested and timber volume 

 lost. 



Rates used in calculating potential growth of 

 conifer timber in the region are shown in table 42. 



92 



