in western Montanao Tables 2 and 3 show values for site classes IV and 

 respectively„ To convert the values found in these tables to other site 

 classes^ use a 12-percent adjustment factor between site classes. For 

 example^ the values found in the site class IV tables when multiplied by 

 112 percent will be converted to corresponding values for site class III, 



The board" foot volume of the reserve stand (trees 10 inches doboh, and 

 larger at logging) and site class are the only stand statistics needed in 

 order to use tables 1^ 2c, and 3» Site classification tables are presented 

 in appendix tables 1 and 2o For example j assume that selective cutting 

 in a ponderosa pine stand averaging site class IV left a reserve stand of 

 4500 beard feet per acre and that the predicted volume of this stand in 

 30 years is required » The average volume of the residual stand 30 years 

 later would be found as follows s (l) enter table 2 at the 4500 board- foot 

 reserve stand class (interpolate between 4^000 and 5s000 board feet)| 

 (2) read the values in the 30-year column „ The volume will be 6920 board 

 feet 30 years after logging representing a net growth of 2420 board feet 

 (6920 bd„ ft, - 4500 bd„ ft,) in 30 years^ or 80„7 board feet periodic annual 

 growth. Ingrowth must be computed independently because it has not been 

 included in these tables » 



ADJUSTING GROV/TH ESTIFiATES FOR ADDITIONAL VARIABLES 



To refine the groivth predict ion j, greater knowledge is required concerning 

 the reserve stand. The following information will be needed? 



lo A stand table of the residual trees in the 1-inch dob„ho 

 class and larger, 



2o Basal area of the reserve stand 9° 6 inches d„boho and larger, 



3o Site index (height in feet of the average dominant and codominant 

 trees at 100 years). See appendix tables 1 and 2, 



4o Age of residual trees - obtained by taking a weighted average 

 of Keen age classes of sample residual trees » 



After basal area has been derived from the stand table,, summarize the 

 survey data from the cut-over stand and compute growth as shown in the 

 following example i 



Reserve stand data? 



1, Volume - 5000 board feet 



2, Basal area - 50 square feet 



3o Site index - 70 feet at 100 years (Site Glass V) 



4o Keen age - 2,6 



5o Gutting cycle - 35 years 



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