Lodgepole pine 



60+ 16 80 



40 - 50 14 100 



Less than 40 Cordwood 



In the actual practice of timber growing, 

 the rotation period tends to be indefinite. 

 Quite probably in the future, the termination 

 of stand growing periods will be decided as 

 each stand takes on merchantable value. Some 

 stands may be held for long periods to produce 

 products to meet particular demands. Other 

 stands may be cut as soon as they become 

 merchantable. 



Although it is desirable to have available 

 an established scale of economically defensible 

 timber growing periods for broad planning 

 purposes, that question need not be dealt with 

 here since this discussion is concerned only 

 with the ranking of opportunities within a 

 particular locality. In ranking stands or areas 

 for management treatment within a Region 

 or within a Forest, the time periods used need 

 not represent a serious source of bias as long 

 as they are reasonably consistent for the 

 entire area. It is important to recognize that 

 in evaluating long-term production oppor- 

 tunities such as timber growing, consistency 

 in procedure and data is very important. 



Table 4. — Rate of stand value increase under two price assumptions — 

 yield data for white pine site index 70 



Age 



Volume 

 per acre 





Assumption 1 







Assumption 2 





Price per 

 M bd. ft. 



Stand value 

 per acre 



Rate of 



value 



increase 



Price per 

 M bd. ft. 



Stand value 

 per acre 



Rate of 



value 



increase 





M bd.ft. 



Dollars 



Percent 



Dollars 



Percent 



50 



19.5 



4.00 



78.00 





4.00 



78.00 





60 



33.8 



6.00 



202.80 



10.0 



6.00 



202.80 



10.0 



70 



44.8 



9.00 



403.20 



7.5 



8.00 



358.40 



5.9 



80 



63.5 



13.00 



825.50 



6.5 



10.00 



635.00 



5.7 



90 



78.0 



18.00 



1,404.00 



5.5 



12.00 



936.00 



4.0 



100 



90.5 



24.00 



2,172.00 



4.5 



14.00 



1,267.00 



3.1 



110 



100.9 



32.00 



3,228.80 



4.0 



16.00 



1,614.40 



2.5 



Source: Haig, Irvine T. Second growth yield, stand and volume tables for the western white pine 

 type. U.S. Dep. Agr. Tech. Bull. 323, 68 pp. 1932. 



site classes. These are not economic rotations 

 in that they are not supported by economic 

 analysis. They may be longer or shorter than 

 is desirable from a timber growing cost-price 

 point of view. As illustrated in table 4, on the 

 basis of yield data for white pine (site index 

 70), only under the first of the two price 

 assumptions (which were arbitrarily chosen) 

 is the rate of value increase greater than 5 per- 

 cent after age 90. The rate of value increase 

 reflected in either set of price assumptions 

 may or may not be reasonable. 



Northern Region tentative tree-size objec- 

 tives and rotations are as follows: 



Site class based on Average 



height at 50 years diameter Rotation 



(Inches) (Years) 



White pine, grand fir, spruce, hemlock 



90+ 22 90 



70- 80 20 100 



50 - 60 18, 110 



40 - 50 ' 16 120 



Larch, Douglas-fir, ponderosa pine 



90+ 20 100 



70 - 80 18 110 



50 - 60 16 120 



40 and less Cordwood 



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