Variations 

 witliin the 

 timber growing 



base 



On the 3.2 miUion acres that comprise the 

 timber growing base in the six Forests there is a 

 wide range of productivity, but there are also 

 other differences. Some stands are less econom- 

 ical to develop than others due to location and 

 type of timber. In fact, high development costs 

 or low product values may in some cases pre- 

 clude utilization in the foreseeable future. 

 Some potentially utilizable areas can't be safely 

 logged until systems that cope with fragile soil 

 problems are developed. Some stands present 

 very difficult silvicultural problems. In other 

 cases nontimber uses and values will preclude 

 capturing the full yield potential of the land. 



Most National Forests have made some at- 

 tempt to adjust their planning to these varia- 

 tions. The Timber Management Division of the 

 Forest Service, Washington Office, prepared a 

 tentative classification scheme for nationwide 

 use in defining subcategories of the timber 

 growing base in 1967. The important point is 

 that on the six Forests studied a significant part 

 of the total 3.2 million-acre timber growing 

 base (as indicated below) is either economically 

 or technologically unavailable at present al- 

 though in the future it presumably will be 

 usable. 



Percent 



Currently usable, both economi- 87 

 cally and technologically 



Unavailable, either economically 

 or technologically 13 



100 



Economic feasibility is almost certain to im- 

 prove with time, but the technologically un- 

 available timber represents a more serious prob- 

 lem. Some of the timber in this currently un- 

 available 13 percent is growing on steep slopes 

 that are unstable and should not be logged 

 using conventional systems, but timber in this 

 category may be obtainable in the future under 

 the new system of logging (fig. 1). Develop- 

 ment of economic long-reach yarding systems 

 such as the skyline and balloon systems that 

 require substantially fewer roads will eventu- 

 ally be necessary to avoid reduction of cutting 

 levels. On a National Forest Uke the Boise, 

 which has much unstable land, there is not 

 much time remaining for achievement of such 

 development. 



6 



