3. For most species, volume and defect were computed using Kemp's equations. 



4. All photo and field data were sent to Ogden, Utah, for processing. Final estimates were 

 based on computer generated statistical summaries of the data. 



DATA RELIABILITY 



Individual cells within tables should be used with caution. Some are based on very small 

 sample sizes, and so may result in a high standard error. The standard error percents shown in 

 tables 1 and 2 were calculated at the 67 percent confidence level. 



Table 1. — Area of State and private forest land in western Montana with percent standard error, 1977 



Item 



Commercial timberland 



Productive reserved^ 



Other forest land: 



Unproductive reserved' 

 Unproductive nonreserved 



Table 2. — Net volume, net annual growth, and annual mortality of growing stock and sawtimber on 

 State and private commercial timberland in western Montana with percent standard error 



Item 



Net volume, 1977: 



Growing stock (M cubic feet) 

 Sawtimber (M board feet) 



Net annual growth, 1976: 



Growing stock (M cubic feet) 

 Sawtimber (M board feet) 



Annual mortality, 1976: 



Growing stock (M cubic feet) 

 Sawtimber (M board feet) 



^Reserved land areas are estimated from aerial photos without field verification; therefore, 

 standard errors are not calculated. 



